What species are these baby birds?

What species are these baby birds?

We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

I'm trying to save these baby birds' lives, and I need to know their species so that I can know how/what to feed them. Please help me ASAP .

If you are in Europe they are juvenile common swift (Apus apus).

There is a website dedicated to them, with a page on how to raise them:

They are very fragile and with the wrong diet they might develop feather deformations. They also require a continuous effort because they eat very often. I raised them a couple of times and when they take off is magnificent but it is easy to do something wrong. If you have some recovery center or expert nearby I suggest to hand them over.

Baby Bird Identification Tips

Baby bird identification can be a challenge as young birds grow, often changing feather lengths, colors, and markings in just a few days. Many birders have been both confused and excited by finding a young bird they didn’t initially recognize, hoping it is a new species to add to their life list. If you understand how baby birds look and behave, however, you won't be fooled. Once you know what you’re looking at, you’ll enjoy watching these amusing young birds go through their early life cycle.

Understanding Animal Behavior

Lesson Objectives

  • Give examples of animal behavior.
  • Explain why animal behavior is important.
  • Describe innate behavior and how it evolves.
  • List ways that behavior can be learned.

Check Your Understanding

  • What is an animal?
  • What are some examples of animals that behave very differently from each other?


  • animal behavior
  • conditioning
  • habituation
  • innate behavior
  • insight learning
  • instinct
  • learned behavior
  • observational learning
  • reflex behaviors

Examples of Animal Behavior

Barking, purring, and playing are just some of the ways that dogs and cats behave. These are examples of animal behavior.

Animal behavior is any way that animals act, either alone or with other animals. Can you think of other examples of animal behavior? What about insects and birds? How do they behave? The pictures in Figure below, Figure below, Figure below, Figure below, Figure below, Figure below, and Figure below show just some of the ways that these and other animals act. Look at the pictures and read about the behaviors. Think about why the animal is behaving that way.

This cat is stalking a mouse. It is a hunter by nature.

This spider is busy spinning a web. If you have ever walked into a spider web, you know how sticky a spider web can be. Why do spiders spin webs?

This mother dog is nursing her puppies. In what other ways do mother dogs care for their puppies?

This bird is using its beak to add more grass to its nest. What will the bird use its nest for?

This wasp is starting to build a nest. Have you seen nests like this on buildings where you live? Why do wasps build nests?

This rabbit is running away from a fox. Did you ever see a rabbit run? Do you think you could run that fast?

This lizard is perched on a rock in the sun. Lizards like to lie on rocks and

Importance of Animal Behavior

Why do animals behave the way they do? The answer to this question depends on what the behavior is. A cat chases a mouse to catch it. A spider spins its sticky web to trap insects. A mother dog nurses her puppies to feed them. All of these behaviors have the same purpose: getting or providing food. All animals need food for energy. They need energy to move around. In fact, they need energy just to stay alive. Baby animals also need energy to grow and develop.

Birds and wasps build nests to have a safe place to store their eggs and raise their young. Many other animals build nests for the same reason. Animals protect their young in other ways, as well. For example, a mother dog not only nurses her puppies. She also washes them with her tongue and protects them from strange people or other animals. All of these behaviors help the young survive and grow up to be adults.

Rabbits run away from foxes and other predators to stay alive. Their speed is their best defense. Lizards sun themselves on rocks to get warm because they cannot produce their own body heat. When they are warmer, they can move faster and be more alert. This helps them escape from predators, as well as find food.

All of these animal behaviors are important. They help the animals get food for energy, make sure their young survive, or ensure that they survive themselves. Behaviors that help animals or their young survive increase the animals’ fitness. You read about fitness in the Evolution chapter. Animals with higher fitness have a better chance of passing their genes to the next generation. If genes control behaviors that increase fitness, the behaviors become more common in the species. This is called evolution by natural selection.

Innate Behavior

All of the behaviors shown in the images above are ways that animals act naturally. They don’t have to learn how to behave in these ways. Cats are natural-born hunters. They don’t need to learn how to hunt. Spiders spin their complex webs without learning how to do it from other spiders. Birds and wasps know how to build nests without being taught. These behaviors are called innate.

An innate behavior is any behavior that occurs naturally in all animals of a given species. An innate behavior is also called an instinct. The first time an animal performs an innate behavior, the animal does it well. The animal does not have to practice the behavior in order to get it right or become better at it. Innate behaviors are also predictable. All members of a species perform an innate behavior in the same way. From the examples described above, you can probably tell that innate behaviors usually involve important actions, like eating and caring for the young.

There are many other examples of innate behaviors. For example, did you know that honeybees dance? The honeybee in Figure below has found a source of food. When the bee returns to its hive, it will do a dance, called the waggle dance. The way the bee moves during its dance tells other bees in the hive where to find the food. Honeybees can do the waggle dance without learning it from other bees, so it is an innate behavior.

When this honeybee goes back to its hive, it will do a dance to tell the other bees in the hive where it found food.

Besides building nests, birds have other innate behaviors. One example occurs in gulls. A mother gull and two of her chicks are shown in Figure below. One of the chicks is pecking at a red spot on the mother’s beak. This innate behavior causes the mother to feed the chick. In many other species of birds, the chicks open their mouths wide whenever the mother returns to the nest. This is what the baby birds in Figure below are doing. This innate behavior, called gaping, causes the mother to feed them.

This mother gull will feed her chick after it pecks at a red spot on her beak. Both pecking and feeding behaviors are innate.

When these baby birds open their mouths wide, the mother instinctively feeds them. This innate behavior is called gaping.

Another example of innate behavior in birds is egg rolling. It happens in some species of water birds, like the graylag goose shown in Figure below. Graylag geese make nests on the ground. If an egg rolls out of the nest, a mother goose uses her bill to push it back into the nest. Returning the egg to the nest helps ensure that the egg will hatch.

This female graylag goose is a ground-nesting water bird. Before her chicks hatch, the mother protects the eggs. She will use her bill to push eggs back into the nest if they roll out. This is an example of an innate behavior. How could this behavior increase the mother goose

Innate Behavior in Human Beings

All animals have innate behaviors, even human beings. Can you think of human behaviors that do not have to be learned? Chances are, you will have a hard time thinking of any. The only truly innate behaviors in humans are called reflex behaviors. They occur mainly in babies. Like innate behaviors in other animals, reflex behaviors in human babies may help them survive.

An example of a reflex behavior in babies is the sucking reflex. Newborns instinctively suck on a nipple that is placed in their mouth. It is easy to see how this behavior evolved. It increases the chances of a baby feeding and surviving. Another example of a reflex behavior in babies is the grasp reflex. This behavior is shown in Figure below. Babies instinctively grasp an object placed in the palm of their hand. Their grip may be surprisingly strong. How do you think this behavior might increase a baby’s chances of surviving?

One of the few innate behaviors in human beings is the grasp reflex. It occurs only in babies.

Learned Behavior

Just about all other human behaviors are learned. Learned behavior is behavior that occurs only after experience or practice. Learned behavior has an advantage over innate behavior. It is more flexible. Learned behavior can be changed if conditions change. For example, you probably know the route from your house to your school. Assume that you moved to a new house in a different place, so you had to take a different route to school. What if following the old route was an innate behavior? You would not be able to adapt. Fortunately, it is a learned behavior. You can learn the new route just as you learned the old one.

Although most animals can learn, animals with greater intelligence are better at learning and have more learned behaviors. Humans are the most intelligent animals. They depend on learned behaviors more than any other species. Other highly intelligent species include apes, our closest relatives in the animal kingdom. They include chimpanzees and gorillas. Both are also very good at learning behaviors.

You may have heard of a gorilla named Koko. The psychologist Dr. Francine Patterson raised Koko. Dr. Patterson wanted to find out if gorillas could learn human language. Starting when Koko was just one year old, Dr. Patterson taught her to use sign language. Koko learned to use and understand more than 1,000 signs. Koko showed how much gorillas can learn. See A Conversation with Koko at for additional information.

Think about some of the behaviors you have learned. They might include riding a bicycle, using a computer, and playing a musical instrument or sport. You probably did not learn all of these behaviors in the same way. Perhaps you learned some behaviors on your own, just by practicing. Other behaviors you may have learned from other people. Humans and other animals can learn behaviors in several different ways.

The following methods of learning will be explored below:

  1. Habituation (forming a habit).
  2. Observational learning.
  3. Conditioning.
  4. Play.
  5. Insight learning.


Habituation is learning to get used to something after being exposed to it for a while. Habituation usually involves getting used to something that is annoying or frightening, but not dangerous. Habituation is one of the simplest ways of learning. It occurs in just about every species of animal.

You have probably learned through habituation many times. For example, maybe you were reading a book when someone turned on a television in the same room. At first, the sound of the television may have been annoying. After awhile, you may no longer have noticed it. If so, you had become habituated to the sound.

Another example of habituation is shown in Figure below. Crows and most other birds are usually afraid of people. They avoid coming close to people, or they fly away when people come near them. The crows landing on this scarecrow have gotten used to a “human” in this place. They have learned that the scarecrow poses no danger. They are no longer afraid to come close. They have become habituated to the scarecrow.

This scarecrow is no longer scary to these crows. They have become used to its being in this spot and learned that it is not dangerous. This is an example of habituation.

Can you see why habituation is useful? It lets animals ignore things that will not harm them. Without habituation, animals might waste time and energy trying to escape from things that are not really dangerous.

Observational Learning

Observational learning is learning by watching and copying the behavior of someone else. Human children learn many behaviors this way. When you were a young child, you may have learned how to tie your shoes by watching your dad tie his shoes. More recently, you may have learned how to dance by watching a pop star dancing on TV. Most likely you have learned how to do math problems by watching your teachers do problems on the board at school. Can you think of other behaviors you have learned by watching and copying other people?

Other animals also learn through observational learning. For example, young wolves learn to be better hunters by watching and copying the skills of older wolves in their pack.

Another example of observational learning is how some monkeys have learned how to wash their food. They learned by watching and copying the behavior of other monkeys.


Conditioning is a way of learning that involves a reward or punishment. Did you ever train a dog to fetch a ball or stick by rewarding it with treats? If you did, you were using conditioning. Another example of conditioning is shown in Figure below. This lab rat has been taught to “play basketball” by being rewarded with food pellets. Conditioning also occurs in wild animals. For example, bees learn to find nectar in certain types of flowers because they have found nectar in those flowers before.

This rat has been taught to put the ball through the hoop by being rewarded with food for the behavior. This is an example of conditioning. What do you think would happen if the rat was no longer rewarded for the behavior?

Humans learn behaviors through conditioning, as well. A young child might learn to put away his toys by being rewarded with a bedtime story. An older child might learn to study for tests in school by being rewarded with better grades. Can you think of behaviors you learned by being rewarded for them?

Conditioning does not always involve a reward. It can involve a punishment instead. A toddler might be punished with a time-out each time he grabs a toy from his baby brother. After several time-outs, he may learn to stop taking his brother’s toys.

A dog might be scolded each time she jumps up on the sofa. After repeated scolding, she may learn to stay off the sofa. A bird might become ill after eating a poisonous insect. The bird may learn from this “punishment” to avoid eating the same kind of insect in the future.

Learning by Playing

Most young mammals, including humans, like to play. Play is one way they learn skills they will need as adults. Think about how kittens play. They pounce on toys and chase each other. This helps them learn how to be better predators when they are older. Big cats also play. The lion cubs in Figure below are playing and practicing their hunting skills at the same time. The dogs in Figure below are playing tug-of-war with a toy. What do you think they are learning by playing together this way?

Other young animals play in different ways. For example, young deer play by running and kicking up their hooves. This helps them learn how to escape from predators.

These two lion cubs are playing. They are not only having fun. They are also learning how to be better hunters.

They are really playing. This play fighting can help them learn how to be better predators.

Human children learn by playing as well. For example, playing games and sports can help them learn to follow rules and work with others. The baby in Figure below is playing in the sand. She is learning about the world through play. What do you think she might be learning?

Playing in a sandbox is fun for young children. It can also help them learn about the world. For example, this child may be learning that sand is soft.

Insight Learning

Insight learning is learning from past experiences and reasoning. It usually involves coming up with new ways to solve problems. Insight learning generally happens quickly. An animal has a sudden flash of insight. Insight learning requires relatively great intelligence. Human beings use insight learning more than any other species. They have used their intelligence to solve problems ranging from inventing the wheel to flying rockets into space.

Think about problems you have solved. Maybe you figured out how to solve a new type of math problem or how to get to the next level of a video game. If you relied on your past experiences and reasoning to do it, then you were using insight learning.

One type of insight learning is making tools to solve problems. Scientists used to think that humans were the only animals intelligent enough to make tools. In fact, tool-making was believed to set humans apart from all other animals.

In 1960, primate expert Jane Goodall discovered that chimpanzees also make tools. She saw a chimpanzee strip leaves from a twig. Then he poked the twig into a hole in a termite mound. After termites climbed onto the twig, he pulled the twig out of the hole and ate the insects clinging to it. The chimpanzee had made a tool to “fish” for termites. He had used insight to solve a problem. Since then, chimpanzees have been seen making several different types of tools. For example, they sharpen sticks and use them as spears for hunting. They use stones as hammers to crack open nuts.

Scientists have also observed other species of animals making tools to solve problems. A crow was seen bending a piece of wire into a hook. Then the crow used the hook to pull food out of a tube.

An example of a gorilla using a walking stick is shown in Figure below. Behaviors such as these show that other species of animals can use their experience and reasoning to solve problems. They can learn through insight.

This gorilla is using a branch as a tool. She is leaning on it to keep her balance while she reaches down into swampy water to catch a fish.

Lesson Summary

  • Animal behavior is any way that animals act. This behavior may be either alone or with other animals.
  • Behaviors that increase fitness can evolve over time. This process occurs by natural selection.
  • Innate behavior is behavior that occurs naturally. This behavior occurs in all members of a species.
  • Learned behavior is behavior that is learned. It occurs only through experience or practice.

Review Questions


1. Give two examples of animal behavior.

3. State three ways that behavior can be learned.

Apply Concepts

4. Identify one drawback of innate behavior.

5. What is the difference between learned behavior and innate behavior?

6. Why is play important for baby animals?

7. Explain how you could use conditioning to teach a dog to sit.

Critical Thinking

8. Explain how egg rolling by graylag geese is likely to have evolved.

9. Describe how the grasp reflex might help a baby survive.

10. A crow was seen dropping nuts on a rock to crack the shells and then eating the nut meats. No other crows in the flock were ever observed cracking nuts in this way. What type of learning could explain the behavior of this crow?

Further Reading / Supplemental Links

CK-12 Foundation. High School Biology, Chapter 34, “Animal Behavior.”

  • Melvin Berger. Dogs Bring Newspapers but Cats Bring Mice: and Other Fascinating Facts about Animal Behavior. Scholastic, 2004.
  • Paolo Casale and Gian Paolo Faescini. Animal Behavior: Instinct, Learning, Cooperation. Barrons Juveniles, 1999.

Points to Consider

Next, we discuss the types of animal behaviors.

  • Did you ever watch a long line of ants marching away from their ant hill? What were they doing? How were they able to work together? What do you think explains group behaviors such as this?

Classification of Birds

There are about 10,000 living species of birds. Almost all of them can fly, but there are several exceptions.

Flightless Birds

Some birds have lost the ability to fly during the course of their evolution. Several flightless birds are shown in Figure below. They include the ostrich, kiwi, rhea, cassowary, and moa. All of these birds have long legs and are adapted for running. The penguins shown in the figure are also flightless birds, but they have a very different body shape. That&rsquos because they are adapted for swimming rather than running.

Flightless Birds. Flightless birds that are adapted for running include the ostrich, kiwi, rhea, cassowary, and moa. Penguins are flightless birds adapted for swimming.

Flying Birds

Birds that are able to fly are divided into 29 orders that differ in their physical traits and behaviors. Table below describes seven of the most common orders. As shown in the table, the majority of flying birds are perching birds, like the honeyeater described in the last row of the table. The order of perching birds has more species than all the other bird orders combined. In fact, this order of birds is the largest single order of land vertebrates.

Human-imprinting in Birds and the Importance of Surrogacy

Imprinting is a form of learning in which an animal gains its sense of species identification. Birds do not automatically know what they are when they hatch – they visually imprint on their parents during a critical period of development. After imprinting, they will identify with that species for life.

Imprinting for wild birds is crucial to their immediate and long-term survival. For example, precocial baby birds (such as ducks, geese, and turkeys) begin the process of imprinting shortly after hatching so that they follow the appropriate adult, providing them with safety.

Imprinting allows baby birds to understand appropriate behaviors and vocalizations for their species, and also helps birds to visually identify with other members of their species so they may choose appropriate mates later in life.

The timing of the imprinting stage varies from species to species, and some species of birds are more susceptible to imprinting inappropriately on human caregivers for reasons not fully understood.

What happens if a bird imprints on humans?

If young birds imprint on humans, they will identify with humans for life. Reversing the imprinting process is impossible – these birds are bonded to humans for life and will identify with humans rather that of their own species.

Imprinting on humans does not mean that birds will be “friendly” toward humans, nor does it mean they necessarily enjoy being near humans. Human-imprinted birds have no fear of people, and this lack of fear can sometimes lead to aggression toward humans. It’s not unusual for an imprinted bird to exhibit territorial behaviors toward humans just as it would with members of its own species.

Human-imprinted birds also frequently have a difficult time communicating with other birds of their own species– vocalizations, postures, and a fear of humans are all things that birds learn from their parents, siblings, and other birds. They are typically not accepted by other birds of their species, likely because human-imprinted birds display odd behaviors and lack the ability to communicate properly.

Ultimately, imprinted birds find themselves in a “gray area” – they cannot appropriately interact with either humans or their own species.

Birds who are human-imprinted are deemed unsuitable for release back into the wild due to these inappropriate interactions. Some of these patients might be appropriate education animals the Wildlife Center has several human-imprinted birds, including Gus the Barred Owl, Jaz the American Crow, Edie the American Kestrel, and Buttercup the Black Vulture.

What does the Center do to prevent young birds from imprinting on humans?

When humans must care for orphaned or injured baby birds, Wildlife Center staffs take special precautions to prevent them from inappropriately imprinting on humans. Human contact is kept to a minimum the rehabilitation staff only handle birds during the feeding and cleaning process. The rehabilitation staff, students, and volunteers do not talk to the patients.

Sometimes caregivers wear masks and hats to disguise human features.

For songbirds, we try to keep babies together in groups of the same species, and this is typically enough to prevent them from imprinting on humans. With our young raptors, placing them with a surrogate parent provides them with the best chance of imprinting on the appropriate species.

Why are surrogates so crucial to the Center?

Surrogates provide an adult role model to young members of their species to counter their interaction with human caregivers. The surrogate parent demonstrates proper behaviors for their species and reinforces their wariness of humans. This enables the young birds to be released back into the wild with appropriate behaviors, vocalizations, and reactions to humans.

The level of interaction between surrogate and baby differs in each situation. Some surrogates take an active role in caring for their “adopted” young by feeding or preening them. Other surrogates show no maternal or paternal instinct, but their presence ensures that the babies can visually imprint on the appropriate species.

Does the Center have any surrogates?

The Center is home to one non-releasable raptor surrogate – Papa G’Ho the Great Horned Owl.

Papa G’Ho was admitted to the Center in 2001 after he sustained injuries to his wings and feet, likely from being hit by a vehicle. Despite rehabilitation, Papa G’Ho never regained his ability to fly silently, which is critical to the hunting success of owls in the wild. Because noisy flight would inhibit his ability to survive independently, he cannot be released back into the wild.

Though he is non-releasable, the Center staff takes great care in keeping Papa G’Ho “wild” to ensure that the owlets he raises will be able to survive and thrive on their own. Papa lives in the patient area of the Wildlife Center, and is not on display for tour groups or open houses.

Papa has helped raise more than two dozen owlets since joining the Center as a surrogate. He plays a crucial role in raising healthy, wild Great Horned Owl orphans at the Center. Watch Papa G'Ho in action in Episode Four of Untamed!

Occasionally, Wildlife Center education animals may fill a temporary surrogate role, if their behavior is appropriate and they are able to be removed from use for outreach programs. The Center also uses adult raptor patients that are healing and medically stable, particularly in cases where the Center does not have an adult of that species available to foster young, such as Barred Owls, Barn Owls, and Bald Eagles.

What about mammals? Do you have to worry about baby mammals imprinting on humans?

The critical development period of mammals differs from birds. Mammals do not visually imprint on their caregivers, but they can become tame or habituated to humans if not handled appropriately. This is particularly true of mammals that have a prolonged juvenile period – White-tailed Deer fawns and Black Bear cubs are prime examples.

Deer fawns are herd animals, and housing fawns together or near each other in the Center’s outdoor enclosures helps to prevent them from becoming habituated to humans. Single fawns raised alone have a higher risk of inappropriately bonding with their human caregiver.

To counteract possible taming and habituation to humans, the Center sometimes houses black bear cubs with an older female bear patient that is healthy and stable. With an older bear as a role model and protector, the cubs are able to better replicate natural behaviors and interactions. Black Bear surrogates have typically spent at least a year in the wild and are able to help instill a wariness of humans in the cubs.

While some young mammals are more vulnerable to habituation to humans, many species of small mammals have a relatively short juvenile stage and are less likely to bond with their human caregivers when appropriate rehabilitation care is given. With all species of baby mammals, the staff strives to be as hands-off as possible, to reduce stress on the animal and risk of taming and habituation.

How can I find out more about surrogacy at the Wildlife Center?

You can stay up-to-date on current patients at the Center by visiting the Critter Corner on our website. Here you’ll find patient stories and updates about some orphaned patients at the Center. You can also find links to our Critter Cam. Papa G’Ho is often featured on the Critter Cam when he is raising young Great Horned Owlets in the spring. Orphaned birds are most frequently admitted to the Center in the spring and summer months, so be sure to check back frequently for new patient information.


Most birds receive parental care (March of the Penguins, anyone?), but megapodes—a group of chicken-like birds native to eastern Australia, New Guinea, Indonesia, and the Philippines—are a big exception.

These birds “do not even directly incubate their eggs,” Roby says. Instead “they build a large mound of decaying vegetation and lay their eggs in the mound.”

According to The Handbook of Bird Biology, the mounds can be “the size of a car.”

The parents do control the mound’s temperature “by removing or adding more vegetation,” says Roby, but once the offspring are born, they dig their way out of the mound and “run off into the brush without ever seeing their parents.”

The chicks can fly within 24 hours.

“Mother crocodiles give their young more post-hatching care than megapodes do,” Roby notes. Indeed, baby crocs are among the very few reptiles that receive parental care, including being carried around in mom’s gigantic mouth. (See video: World’s Deadliest: Killer Croc Carries Babies in Jaws)

Beak Deformities in Landbirds

Over the past 20 years, Alaskans have witnessed a startling increase of beak deformities among Black-capped Chickadees and other species of resident birds. This disease, called avian keratin disorder (AKD), is characterized by debilitating beak overgrowth and other abnormalities of keratinized tissues. Affected birds have difficulty feeding and preening, and may suffer high rates of mortality.

A Black-capped Chickadee with a deformed beak trying to eat at a suet ball

(Credit: Sherry Shiesl. Courtesy: Sherry Shiesl)

We began research in 1999, and have since identified more than 3,000 affected Black-capped Chickadees in Alaska—the highest concentration of gross deformities ever recorded in a wild bird population! Increasing numbers of other species, including Northwestern Crows, Downy Woodpeckers, Steller’s Jays, and Black-billed Magpies have also been observed with beak deformities throughout the state. Growing numbers of reports from North America and Europe suggest that AKD may be spreading to a larger geographic area.

In 2016, we identified a novel picornavirus (Poecivirus) in Alaskan Black-capped Chickadees with AKD. We’ve subsequently confirmed a strong association between Poecivirus and beak deformities in chickadees and detected a closely related virus in other species with similar beak deformities. Together, this evidence suggests that Poecivirus is a likely candidate cause of AKD. Our current investigations are focusing on understanding more about this virus, including how it may be contributing to beak deformities, whether it occurs in multiple species, and how it is transmitted. Previously, we examined potential factors, such as environmental contaminants, nutritional deficiencies, and parasites, found no clear evidence linking these to AKD in Alaskan birds.

Reports from the public help us to determine where and how many birds are affected. If you see a bird with a beak deformity, please contact us.

These Are The World's Weirdest Birds

There are almost 10,000 bird species flying the skies, roaming the lands, and diving the waters of our planet. Some of them are pretty similar to one another, perhaps because the two species diverged only relatively recently. But some of them are so unique you won't believe they're not made up.

The species listed below come from a recent paper in Current Biology , which aimed to identify the species most in need of our conservation efforts. As I wrote in Conservation Magazine last week, the researchers measured each bird's evolutionary distinctness. "It's a way to assess how evolutionarily unique a species is by comparing its genome with the genomes of its closest relatives. Those who are least related to - or more different from - their closest phylogenetic relatives would be more evolutionarily distinct." As a result of being so evolutionarily distinct, some of the birds with the highest levels are also quite unique.

Here are some of the weirder birds we found while browsing the data, which is freely available .

1. Kagu

The only place on Earth you'll find a wild Kagu is in New Caledonia , a small island east of Australia. It may look like your average bird, but it's the only surviving member of both its genus and its family. Mating pairs, which last quite a long time and possibly for life, occupy large territories, 22-62 acres in size. For most of the year, the male and female live in their own, but each breeding season they come together to co-incubate a single egg. The species is so emblamatic of New Calendonia, that the nation's TV station used to play its song each night as it went off the air.

Why is it weird? It's the only bird species that has "nasal corns," small structures over the nasal openings. It's thought that they evolved to prevent dust and other particles from entering the nose, since the Kagu spends so much time rooting around the dirt with its beak its prey.

2. Christmas Island Frigatebird

The slightly awkward looking Christmas Island Frigatebird comes from, you guessed it, Christmas Island, a small Australian territory in the Indian Ocean. They're particularly threatened by the introduced yellow crazy ant, which you may remember from National Geographic's Great Migrations as the species that eats the Christmas Island crabs. Alive.

Why is it weird? The Christmas Island Frigatebird captures its prey in one of two ways. One is it eats flying fish while they're above the sea's surface, relying on marine predators to drive the fish out of the water. That's not that weird. The second, more interesting way, this: while in flight, the bird steals food that other seabirds and gulls have managed to nab themselves, all while airborne. Scientists call them "aerial kleptoparasites." We like to call them "sky pirates."

3. Philippine Eagle

This impressive raptor is the world's longest, measuring some three feet from beaktip to tail, though it isn't quite the world's heaviest (Steller's Sea Eagle) or bulkiest (Harpy Eagle). As an apex predator, it was once called the "Philippine Monkey-Eating Eagle," because it was believed that it preyed only on monkeys. We now know that it hunts much more opportunistically, taking whatever meat it can find, including, yes, monkeys. The fact that it doesn't exclusively dine on primate flesh doesn't make it any less terrifying.

Why is it weird? If being the longest eagle in the world and dining on monkey meat isn't enough, it's also got a fascinating relationship with human culture. It was made the national bird of the Philippines on July 4, 1995. As a result, if you kill one, you can look forward to spending twelve years in prison.

4. Kakapo

This magnificent bird is also one of the world's rarest. By the end of 2013, there were only an estimated 124 of them in existence. Like many island predators, it evolved on New Zealand with no natural predators of its own. That's why it was so vulnerable to predation by the predators that modern humans brought with them to the island: cats and rats (obviously), but also ferrets and stoats.

Why is it weird? This parrot has so many unique features its hard to know where to begin. It is the world's heaviest and only flightless parrot. It is nocturnal, which is unusual for parrots, and is the only parrot in the world known to mate by lekking . In a lek, males gather in an arena where they form themselves into a sort of mating buffet. The females come by, watch their displays, and pick out their favorite males. It's common in ungulates like deer, and is known to occur among some birds, like prairie chickens, but the kakapo is the world's only parrot to do it. But perhaps their weirdest trait is also ultimately the source of their eventual downfall: they only breed three times, on average, each decade. Breeding occurs only when the fruit of the rimu tree (Dacrydium cupressinum) is in relative abundance.

5. California Condor

I've you've been reading Animals.io9 for a while, then you know we're already a little bit obsessed with California Condors. Using one of the most fascinating sorts of science-based conservation, zookeepers are raising baby chicks in captivity by putting condor puppets on their hands. It's one of the world's longest-living birds, with lifespans stretching up to six decades in the wild. That is, if they can avoid poaching or lead poisoning. They're also eaters of death, feasting primarily on carrion. All living California condors are descended from just 22 individuals, captured in 1987 for a captive breeding program. As of May 2013, there are now 237 living in the wild and 198 in captivity.

Why is it weird? The bird has the largest wingspan of any in North America, and as a result it can be mistaken for a small airplane. In fact, according to John Nielson, author of Condor: To the Brink and Back the birds are confused for aircraft more often than they're confused for other birds.

6. Oilbird

The oilbird, known locally in northern South America as guácharo, is a curious little nocturnal cave-dwelling frugivore. It finds its food by echolocation, much as bats and dolphins do, though some of the frequencies they use are actually audible to humans. It's the world's only flying nocturnal fruit-eating bird (the kakapo, above, is flightless together, the pair are the world's only nocturnal fruit eaters).

Why is it weird? As its name implies, the oilbird is so oily that people used to hunt them and boil them down to extract their oil for use as fuel. It's got 80 million years of evolutionary distinctness, making it one of the most evolutionarily distinct birds in existence.

7. Hoatzin

We've saved the best for last. This beautiful, pheasant-sized bird is native to South America's Amazon and Orinoco deltas. Like many of the birds on our list, it's the only species of it's genus, which is part of why it's so evolutionarily distinct. They're herbivores, feeding mainly on leaves, fruits, and flowers, but because of the way they digest those plant parts, the birds wind up quite stinky. In fact, the Hoatzin is also known locally as the "Stinkbird" for their vaguely manure-like odor. For that reason, it isn't threatened by human poaching it's sort of a last-resort meal. Youɽ have to be really, really hungry to try to capture one of these critters.

Why is it weird? There's a very good reason it's such a foul smelling bird. The Hoatzin has a digestive system unlike any other bird, and actually more like a cow . They have a foregut that they use to break down the plants they eat using bacterial fermentation. It's not a rumen, as ruminants like cattle have instead, evolution operated on part of their digestive anatomy called the crop , a feature common to birds, to make it function much like a cow's rumen. As a result, the crop is so large that it displaces muscles that otherwise would have been used for flight. Hoatzins can still fly, just not all that well.

The Hoatzin has another feature unique among all the world's birds, and it's one that makes it a strong contender to inspire the next SyFy horror flick : it's got two claws on each of its wings!

The wing-claws let the chicks move about tree branches without falling into the water below as soon as they hatch. It's an important feature to avoid becoming the next meal of a Great Black Hawk. When a hawk attacks, the mature Hoatzins fly about to distract the predator, while the chicks hide under thicker cover. If spotted, the chicks do an avian version of stop-drop-and-roll. They plunge into the water, swim away, and use their claws to haul themselves back onto land, up the tree, and into the nest. Because of its claws, some researchers have wondered if the Hoatzin was a direct descendent of Archaeopteryx, which had three claws on each wing. Others think the claws are a more recent adaptation, having emerged as a result of the selective pressure caused by predation. Either way, the Hoatzin may be the most badass bird around. They're a good reminder that dinosaurs still live among us.

Study of Darwin's finches reveals that new species can develop in as little as two generations

A new study illustrates how new species can arise in as little as two generations. The study tracked Darwin's finches on the Galápagos island of Daphne Major, where a member of the G. conirostris species (pictured) arrived from a distant island and mated with a resident finch of the species G. fortis. The offspring developed into a new species that the researchers call the Big Bird lineage.

The arrival 36 years ago of a strange bird to a remote island in the Galápagos archipelago has provided direct genetic evidence of a novel way in which new species arise.

On Nov. 23 in the journal Science, researchers from Princeton University and Uppsala University in Sweden report that the newcomer belonging to one species mated with a member of another species resident on the island, giving rise to a new species that today consists of roughly 30 individuals.

The study comes from work conducted on Darwin’s finches, which live on the Galápagos Islands in the Pacific Ocean. The remote location has enabled researchers to study the evolution of biodiversity due to natural selection under pristine conditions.

The direct observation of the origin of this new species occurred during field work carried out over the last four decades by B. Rosemary Grant and Peter Grant, a wife-and-husband team of scientists from Princeton, on the small island of Daphne Major.

"The novelty of this study is that we can follow the emergence of new species in the wild," said B. Rosemary Grant, a senior research biologist, emeritus, and a senior biologist in the Department of Ecology and Evolutionary Biology. "Through our work on Daphne Major, we were able to observe the pairing up of two birds from different species and then follow what happened to see how speciation occurred."

In 1981, a graduate student working with the Grants on Daphne Major noticed the newcomer, a male that sang an unusual song and was much larger in body and beak size than the three resident species of birds on the island.

"We didn't see him fly in from over the sea, but we noticed him shortly after he arrived. He was so different from the other birds that we knew he did not hatch from an egg on Daphne Major," said Peter Grant, the Class of 1877 Professor of Zoology, Emeritus, and a professor of ecology and evolutionary biology, emeritus.

The bird is a member of the G. fortis species, one of two species that interbred to give rise to the Big Bird lineage.

The researchers took a blood sample and released the bird, which later bred with a resident medium ground finch of the species Geospiz fortis, initiating a new lineage. The Grants and their research team followed the new "Big Bird lineage" for six generations, taking blood samples for use in genetic analysis.

In the current study, researchers from Uppsala University analyzed DNA collected from the parent birds and their offspring over the years. The investigators discovered that the original male parent was a large cactus finch of the species Geospiza conirostris from Española island, which is more than 100 kilometers (about 62 miles) to the southeast in the archipelago.

The remarkable distance meant that the male finch was not able to return home to mate with a member of his own species and so chose a mate from among the three species already on Daphne Major. This reproductive isolation is considered a critical step in the development of a new species when two separate species interbreed.

The offspring were also reproductively isolated because their song, which is used to attract mates, was unusual and failed to attract females from the resident species. The offspring also differed from the resident species in beak size and shape, which is a major cue for mate choice. As a result, the offspring mated with members of their own lineage, strengthening the development of the new species.

Researchers previously assumed that the formation of a new species takes a very long time, but in the Big Bird lineage it happened in just two generations, according to observations made by the Grants in the field in combination with the genetic studies.

The direct observation of the origin of a new species occurred during field work carried out over the last four decades by B. Rosemary Grant and Peter Grant, a wife-and-husband team of scientists from Princeton, on the small island of Daphne Major in the Galápagos Islands in the Pacific Ocean.

All 18 species of Darwin’s finches derived from a single ancestral species that colonized the Galápagos about one to two million years ago. The finches have since diversified into different species, and changes in beak shape and size have allowed different species to utilize different food sources on the Galápagos. A critical requirement for speciation to occur through hybridization of two distinct species is that the new lineage must be ecologically competitive — that is, good at competing for food and other resources with the other species — and this has been the case for the Big Bird lineage.

"It is very striking that when we compare the size and shape of the Big Bird beaks with the beak morphologies of the other three species inhabiting Daphne Major, the Big Birds occupy their own niche in the beak morphology space," said Sangeet Lamichhaney, a postdoctoral fellow at Harvard University and the first author on the study. "Thus, the combination of gene variants contributed from the two interbreeding species in combination with natural selection led to the evolution of a beak morphology that was competitive and unique."

Schematic illustration of the evolution of the Big Bird lineage on the Daphne Major island in the Galápagos archipelago. Initially an immigrant large cactus finch male (Geospiza conirostris) bred with a medium ground finch female (Geospiza fortis). Their offspring bred with each other and established the Big Bird lineage. Photos © K. Thalia Grant for G. conirostris and Peter R. Grant for the remainder. Reproduced with permission from K.T. Grant, and Princeton University Press, which first published the remaining images in "40 Years of Evolution"

The definition of a species has traditionally included the inability to produce fully fertile progeny from interbreeding species, as is the case for the horse and the donkey, for example. However, in recent years it has become clear that some closely related species, which normally avoid breeding with each other, do indeed produce offspring that can pass genes to subsequent generations. The authors of the study have previously reported that there has been a considerable amount of gene flow among species of Darwin’s finches over the last several thousands of years.

The breeding of two distinct parent species gave rise to a new lineage (termed "Big Bird" by the researchers). This lineage has been determined to be a new species. This image is of a member of the Big Bird lineage.

One of the most striking aspects of this study is that hybridization between two distinct species led to the development of a new lineage that after only two generations behaved as any other species of Darwin’s finches, explained Leif Andersson, a professor at Uppsala University who is also affiliated with the Swedish University of Agricultural Sciences and Texas A&M University. "A naturalist who came to Daphne Major without knowing that this lineage arose very recently would have recognized this lineage as one of the four species on the island. This clearly demonstrates the value of long-running field studies," he said.

It is likely that new lineages like the Big Birds have originated many times during the evolution of Darwin’s finches, according to the authors. The majority of these lineages have gone extinct but some may have led to the evolution of contemporary species. "We have no indication about the long-term survival of the Big Bird lineage, but it has the potential to become a success, and it provides a beautiful example of one way in which speciation occurs," said Andersson. "Charles Darwin would have been excited to read this paper."

The study was supported by the Galápagos National Parks Service, the Charles Darwin Foundation, the National Science Foundation, the Knut and Alice Wallenberg Foundation, and the Swedish Research Council.

The study, "Rapid hybrid speciation in Darwin's finches," by Sangeet Lamichhaney, Fan Han, Matthew T. Webster, Leif Andersson, B. Rosemary Grant and Peter R. Grant, was published in the journal Science on Nov. 23.

Uppsala University contributed to the content of this press release.

When parenting goes cuckoo

Brood parasites leave their young with another animal who acts as a “foster parent.” Here, the foster parent is a cape robin-chat (right). It is feeding an enormous chick of another species, a red-chested cuckoo (left).

Alandmanson/Wikimedia Commons (CC BY-SA 4.0)

Share this:

In Europe, a bird called the common cuckoo uses a sneaky strategy to raise its babies. First, a female cuckoo finds a nest built by a bird of a different species. For example, it might be a great reed warbler. Then, she sneaks into the warblers’ nest, lays an egg and flies away. The warblers often accept the new egg. Indeed, they take care of it along with their own eggs.

The cuckoo chick hatches before the warbler chicks. And it wants all the food from the warbler parents for itself. So the young cuckoo pushes the warbler eggs onto its back, one by one. It braces its feet on the sides of the nest and rolls each egg over the edge. Smash!

“It’s amazing,” notes Daniela Canestrari. She’s a biologist who studies animal behavior at the University of Oviedo in Spain. These chicks “kind of stand up until the egg just falls out.”

It’s not so amazing for the warblers. For some reason, the warbler parents keep feeding the cuckoo chick, even as their own offspring are gone. “This is very bad for the parents because they lose all of their chicks,” Canestrari says.

The common cuckoo is one example of a brood parasite. Such animals trick other animals into raising their young. They sneak their eggs into other parents’ nests.

Brood parasites are “basically looking for foster parents,” says Mark Hauber, a biologist. He studies animal behavior at the University of Illinois at Urbana-Champaign. The “foster parents” are also called “hosts.” Those hosts then feed and protect the parasite’s offspring.

Scientists find this behavior intriguing. And they have witnessed it in birds, fish and insects.

Some researchers are studying whether hosts recognize the alien eggs. Others are exploring how hosts evolve defenses against such parasites. And surprisingly, one team has learned that brood parasites aren’t all bad. Sometimes, they help actually aid their foster family.

A cuckoo chick pushes reed warbler eggs out of their nest. For some reason, the reed warbler parents still keep feeding the cuckoo chick as if it were one of their own.
Artur Homan

Here, raise my kids

Some animals don’t care for their young. They just leave their offspring to fend for themselves. Other animals take a more active role. They forage for food to feed their growing young. They also protect their young from predators and other dangers. Such duties up the chance their offspring will make it to adulthood.

But caring for young animals requires a lot of energy. Adults who gather food for babies might instead have spent that time feeding themselves. Defending their nest against predators could also get a parent injured or killed.

Brood parasites that trick someone else into doing the work can reap the benefits of raising offspring — without the costs. All animals want to pass on copies of their own genes to the next generation. The more young that survive, the better.

Not all brood parasites are as nasty as the common cuckoo. Some parasitic bird chicks grow up alongside their host nestmates. But these nest-crashers can still cause problems. For example, a parasitic chick might hog food. Then some chicks in the foster family could starve.

Some hosts fight back. They learn to recognize foreign eggs and toss them. And if hosts see a parasitic bird, they attack it. Among insects, hosts beat up and sting intruders.

But hosts sometimes just accept the brood parasite. Its egg may look so similar to their own that the hosts can’t tell them apart. After an egg hatches, hosts may suspect a chick isn’t theirs, but they don’t want to risk neglecting it. If they’re wrong, they would have killed one of their young. So they raise the young parasite alongside their own offspring.

Beige egg, blue egg

How closely must an egg resemble its hosts’ for those foster parents to accept it? Some researchers have studied this by using models of eggs made from materials such as clay, plaster or wood. Hauber tried a more advanced technique.

He made fake eggs with 3-D printing. This technology can create 3-D objects out of plastic. A machine melts the plastic, then deposits it in thin layers to build up the desired shape.

With this technique, the researchers created fake eggs with subtle shape differences. Then they watched to see how hosts responded to the different shapes.

Hauber’s team focused on brown-headed cowbirds. These brood parasites live in North America. They lay eggs in the nests of American robins.

Robin eggs are bluish-green and don’t have spots. In contrast, cowbird eggs are beige and spotted. They also are quite a bit smaller than robin’s eggs. Often, the robin throws out the cowbird egg.

Hauber wondered how much the cowbird eggs would need to resemble a robin’s to be accepted. To find out, his team 3-D-printed 28 fake eggs. The researchers painted half of the eggs beige and the other half bluish-green.

All the faux eggs were roughly within the size range of real cowbird eggs. But some were slightly wider or longer than average. Others were a bit thinner or shorter than usual.

The team then visited robin nests in the wild. The researchers snuck fake eggs into the nests. Over the next week, they checked to see if the robins kept — or rejected — the fake eggs.

The results suggest that cowbirds would have more success in robin nests if they evolved to lay bluish-green eggs.

Robins threw out 79 percent of the beige eggs. But they kept all the bluish-green eggs, even though they were smaller than normal robin eggs. Minor shape differences among the fake bluish-green eggs didn’t seem to make a difference. “No matter the shape, they accept those eggs,” Hauber reports. So, he concludes, “The robin seems to pay less attention to size and more to color.”

Alien babies

Brood parasitism also happens in fish. But so far, scientists have found it in only one species: the cuckoo catfish. This fish lives in Lake Tanganyika (Tan-guh-NYEE-kuh) in eastern Africa.

Its hosts are fish species called mouthbrooding cichlids (SIK-lidz). During mating, a female cichlid lays her eggs on the lake floor. Then she quickly gathers the eggs in her mouth and carries them for a few weeks. After the eggs hatch, the little fish swim out of her mouth.

The cuckoo catfish messes up that process. When a female cichlid lays eggs, the female catfish rushes in and lays her eggs at the same spot or nearby. The cichlid and catfish eggs now get mixed up. The cichlid later scoops up her own eggs — and those of the catfish.

The baby catfish hatch inside the cichlid’s mouth and then go on to eat her own eggs. The hatchlings that eventually emerge from her mouth look very different from a cichlid.

“It would be like a human female giving birth to an alien,” says Martin Reichard. He is a biologist who studies how animals interact with their environment. Reichard works at the Czech Academy of Sciences in Brno, Czech Republic.

Reichard wondered if cichlids had evolved defenses against the cuckoo catfish. Some cichlid species have lived in Lake Tanganyika with the catfish for a long time. But mouthbrooding cichlids in other African lakes have never encountered cuckoo catfish.

To investigate, his team observed cuckoo catfish and cichlids in the lab. One cichlid species was from Lake Tanganyika, and others came from different lakes. The researchers placed cuckoo catfish with various cichlid species in tanks.

Later, Reichard’s team caught the female cichlids. They squirted water into each fish’s mouth. This flushed out the eggs. Lake Tanganyika cichlids, they found, were much less likely than the other cichlids to carry catfish eggs.

The researchers wondered if Lake Tanganyika cichlids spit out the catfish eggs. To find out, they put female Lake Tanganyika cichlids in one tank. Female cichlids from another African lake, called Lake George, went in a separate tank.

Next, the scientists collected catfish eggs and fertilized them in a dish. They squirted six catfish eggs into each female cichlid’s mouth. Over the next day, the team counted how many catfish eggs ended up on each tank’s floor.

Only seven percent of the Lake George cichlids spit out catfish eggs. But 90 percent of the Lake Tanganyika cichlids had spit out catfish eggs.

It’s not clear how the Lake Tanganyika cichlids know to reject the intruders. Maybe the catfish eggs feel different in the cichlid’s mouth because of their shape and size. Or maybe they taste different.

That defense comes with a downside, however. Sometimes Lake Tanganyika cichlids spit out their own eggs along with catfish eggs. So the price of evicting the parasitic eggs was to sacrifice some of their own. Argues Reichard, that cost is “quite high.”

Smelly roommates

Brood parasites aren’t always bad news. Canestrari has found that some parasitic chicks that aid their foster family.

Canestrari studies a host species called the carrion crow. At first, she wasn’t focusing on brood parasitism. She just wanted to learn about crow behavior.

But some crow nests had been parasitized by great spotted cuckoos. When the cuckoo eggs hatched, the chicks didn’t push crow eggs out of the nest. They grew up alongside crow chicks.

“At a certain point, we noticed something that really puzzled us,” Canestrari says. Nests containing a cuckoo chick seemed more likely to succeed. By that she means that at least one crow chick survived long enough to fledge, or fly out on its own.

The researchers wondered if the reason had something to do with predators. Falcons and wild cats sometimes attack crow nests, killing all the chicks. Could the cuckoos be helping to defend nests from these attackers?

The researchers knew that when they picked up cuckoos, the birds squirted out a stinky liquid. They “always, always produce this terrible substance, which is absolutely disgusting,” Canestrari says. She wondered if cuckoos were sliming predators with the liquid.

So the scientists found crow nests containing a cuckoo chick. They moved some cuckoos to crow nests that weren’t parasitized. Then the researchers monitored whether the nests succeeded. They also watched nests that had never contained a cuckoo chick.

About 70 percent of crow nests with added cuckoo chicks succeeded. This rate was similar to that of chicks in parasitized nests that kept their cuckoos.

But among nests whose cuckoo chicks were removed, only about 30 percent succeeded. And this rate was similar to what is seen in nests that never held a cuckoo.

“The presence of the cuckoo was causing this difference,” Canestrari concludes.

Then the researchers tested whether predators disliked the cuckoo’s stinky spray. They collected the liquid in a tube. Later, they smeared this stuff on raw chicken meat. Then they offered the doctored meat to cats and falcons.

The predators turned up their noses. Most of the cats “didn’t even touch the meat,” Canestrari says. The birds tended to pick it up, then reject it.

Classroom questions

So cuckoo chicks do seem to protect crow nests. “The host is gaining some kind of benefit,” she says. “In some circumstances, a cuckoo chick is not a bad thing.”

Scientists find brood parasites fascinating because they’re rare. Most birds care for their own young instead of shoving the work onto someone else. Notes Hauber, brood parasites “are the exception to the rule.”

Note: This article was updated on October 15, 2019, to fix the definition of a brood parasite and clarify the experiment described in the final section.

Power Words

3-D printing A means of producing physical items — including toys, foods and even body parts — using a machine that takes instructions from a computer program. That program tells the machine how and where to lay down successive layers of some raw material (the “ink”) to create a three-dimensional object.

alien A non-native organism.

average (in science) A term for the arithmetic mean, which is the sum of a group of numbers that is then divided by the size of the group.

behavior The way something, often a person or other organism, acts towards others, or conducts itself.

biology The study of living things. The scientists who study them are known as biologists.

brood A group of related animals that emerges in a specific region in the same year. Depending on the animal type, the collective group is sometimes also known as a year class. (verb) The act of guarding and/or incubating eggs.

carrion The dead and rotting remains of an animal.

cichlids A freshwater fish that has become popular in the aquarium trade. This animal’s family is large and diverse. It includes at least 1,650 species, many of which are eaten. Although found all over the world, they are most diverse in Africa and South America.

clay Fine-grained particles of soil that stick together and can be molded when wet. When fired under intense heat, clay can become hard and brittle. That’s why it’s used to fashion pottery and bricks.

crow The characteristic loud cry of a rooster. (in biology) A type of large black bird with a complex social structure that perches in trees and is known for its boisterous call.

defense (in biology) A natural protective action taken or chemical response that occurs when a species confront predators or agents that might harm it. (adj. defensive)

environment The sum of all of the things that exist around some organism or the process and the condition those things create. Environment may refer to the weather and ecosystem in which some animal lives, or, perhaps, the temperature and humidity (or even the placement of things in the vicinity of an item of interest).

evolve (adj. evolving) To change gradually over generations, or a long period of time. In living organisms, such an evolution usually involves random changes to genes that will then be passed along to an individual’s offspring. These can lead to new traits, such as altered coloration, new susceptibility to disease or protection from it, or different shaped features (such as legs, antennae, toes or internal organs).

faux Meaning false or fake. Faux fur, for instance, would not be made from animal products but from some manufactured fibers.

fledge The first time a young bird develops wing feathers and is able to fly.

forage To search for something, especially food. It’s also a term for the food eaten by grazing animals, such as cattle and horses.

gene (adj. genetic) A segment of DNA that codes, or holds instructions, for a cell’s production of a protein. Offspring inherit genes from their parents. Genes influence how an organism looks and behaves.

generation A group of individuals (in any species) born at about the same time or that are regarded as a single group. Your parents belong to one generation of your family, for example, and your grandparents to another. Similarly, you and everyone within a few years of your age across the planet are referred to as belonging to a particular generation of humans.

hatchling A young animal that recently emerged from its egg.

model A simulation of a real-world event (usually using a computer) that has been developed to predict one or more likely outcomes. Or an individual that is meant to display how something would work in or look on others.

parasite An organism that gets benefits from another species, called a host, but doesn’t provide that host any benefits. Classic examples of parasites include ticks, fleas and tapeworms.

predator (adjective: predatory) A creature that preys on other animals for most or all of its food.

range The full extent or distribution of something. For instance, a plant or animal’s range is the area over which it naturally exists. (in math or for measurements) The extent to which variation in values is possible. Also, the distance within which something can be reached or perceived.

risk The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. (For instance: Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.)

species A group of similar organisms capable of producing offspring that can survive and reproduce.

strategy A thoughtful and clever plan for achieving some difficult or challenging goal.

subtle Some feature that may be important, but can be hard to see or describe. For instance, the first cellular changes that signal the start of a cancer may be visible but subtle — small and hard to distinguish from nearby healthy tissues.


Journal: D. Canestrari et al. From parasitism to mutualism: Unexpected interactions between a cuckoo and its host. Science. Vol. 343, Mar. 21, 2014, p. 1350. doi: 10.1126/science.1249008.