Key concepts
Animals
Biology
Adaptations
Evolution
Introduction
Have you ever wondered how different species animals can survive—and thrive—in all sorts of environments, even when the animals seem closely related? For example, polar bears swim in the Arctic Ocean where they face negative temperatures whereas other bears live in warm, southern California. How do they do it? The answer is adaptations! Their bodies have special features that allow them to live in their environments. In this activity you'll investigate what the adaptations of birds in your area tell you about those birds' lifestyles. Get ready to do some bird-watching!
Background
If you were an animal with a thick layer of fat under your skin and a heavy coat of fur, such as a polar bear, would you live in a tropical forest? No way! You'd be way too hot! But if you lived in the cold of the Arctic, near the North Pole, these adaptations would be necessary to keep you warm. All creatures have adaptations. Some adaptations help animals deal with the climate, such as the polar bear example above. Other adaptations help animals move better in their environments, blend in with their surroundings so they don't get eaten by predators or successfully hunt for their dinner.
Birds are animals with a lot of specific and useful adaptations. A major one is the shapes of their feet. Have you ever noticed that one kind of bird’s foot can be wildly different from another type’s? For example, chickens and ducks are both birds, but they have very differently shaped feet. Chicken feet have relatively long skinny toes with strong, sharp nails, whereas ducks have webbed feet. Chickens' feet allow them to scratch at the ground to find insects and seeds to eat whereas ducks, who live in the water, have webbing between their toes that helps them paddle.
Materials
• Unless you're going to a zoo or pet store soon, you'll want a bird-watcher’s field guide to identify birds in your area. Alternatively, you could use online resources to identify the birds you see.
• A place to observe birds. (This could be your backyard—especially if you have a bird feeder or birdbath—or a park, field, forest, beach, aviary at a zoo, pet store or farm that has different types of birds.)
• Binoculars, which are only needed if you will be watching birds from a distance. Inexpensive ones are fine.
• Sheet of paper
• Pen or pencil
Preparation
• Get ready to do some bird-watching. Unless you're going to a zoo or pet store, have a local bird field guide ready or have access to an online resource, so you can identify local species. A good online resource you could use is eNature.com .
Procedure
• Bring a sheet of paper, a pen or pencil and your field guide (or access to an online resource) to one of the bird-observation places you decided on. If needed, also bring binoculars. Observe the birds there. (Be sure to have an adult accompany you.) What kind of birds do you see?
• Identify the different species of birds you see. (If you are at a zoo, pet store or other place where the bird species are labeled or simple to identify, this will be easy.) Use a field guide or online resource to do this.
• What species do you see? On your sheet of paper, write their names down.
• Look at the feet of each bird species. What type of feet do they have? Write down one of the following seven types of feet for each species:
o Climbing: Two toes in front, two toes in back
o Swimming: Webbed feet
o Running: Strong-legged with two or three thick toes, all facing forward
o Perching: Three toes in front, one toe in back
o Grasping: Clawlike feet with curved talons
o Scratching: Four toes, all with strong nails for digging into the ground
o Wading: Long, thin legs and toes
• Tip: If it is difficult to clearly see any bird's feet, you could look for pictures (online or in your field guide) of birds that more clearly show their feet.
• Try to make observations for at least five species. The more you observe, the better your results should be!
• Based only on the type of feet each bird has, predict what kind of lifestyle you think that type of bird has. In other words, where do you think it spends most of its time? Is it usually perched in a tree, climbing trees, on the ground or swimming in the water?
• Do some research on each species of bird to find out where it actually spends its time. To do this, you could use the field guide or online resources. (Again, you could use the eNature.com Web site or other resources listed in the "More to explore" section on the next page.) You'll want to look into where each bird nests, roosts (sleeps) and forages (gets food). Where does each bird spend most of its time?
• Based on your results, how accurate an indicator was each bird's foot type for the kind of lifestyle it usually leads?
• Extra: In this activity you looked at the general lifestyle of birds, but there are many aspects that go into birds’ lifestyles, such as where they nest, where they roost and how they get food. Pick one of these aspects and investigate again how well a bird's foot type is as an indicator of that part of its lifestyle. How good is a bird's foot type at, for example, predicting how it gets its food?
• Extra: Try this activity again, but this time compare the birds' beaks instead of their feet. How well can a bird's beak be used to predict its lifestyle and/or specifically what it eats? Do birds with different types of beaks eat different things?
• Extra: Pick two diverse habitats, like the beach and a forest, and investigate the species of birds in those areas. Do birds in the same habitat have similar types of feet? How about birds in different habitats?
Observations and results
Were you able to use the type of foot that each species of bird has to usually accurately predict that bird's lifestyle?
Chickens' feet are adapted to allow them to scratch at the ground and find insects and seeds to eat, whereas ducks' feet are adapted to help them paddle in the water. In this activity you should have seen that a bird's feet are usually a good indicator of the type of lifestyle it leads. For example, the common house sparrow (Passer domesticus) has perching-type feet, and it indeed spends a lot of time perching on trees, other plants and structures in different environments. Similarly, lovebirds (of the genus Agapornis), African grays (Psittacus erithacus), cockatiels (Nymphicus hollandicus) and other parrots you might find in pet stores and aviaries have climbing feet. Not only do they frequently climb in captivity but in the wild they also spend much time doing this—often climbing on and nesting within trees in wooded areas. The type of feet a bird has, however, might not reflect every aspect of its lifestyle. For example, many birds have climbing- or perching-type feet but mostly forage on the ground. This includes mourning doves (Zenaida macroura), the American robin (Turdus migratorius), some kinds of parrots, along with many other bird species. These adaptations might still be left over from their ancestral species that lived in different environments.
More to explore
All about Birds, from The Cornell Lab of Ornithology
Bird Feet, from Fernbank Science Center
Field Guides: Birds, from eNature.com
Can You Predict a Bird's Lifestyle Based on Its Feet?, from Science Buddies
This activity brought to you in partnership with Science Buddies
