Late summer is an important time for birds. Fledglings are finally off on their own and the strenuous nesting period is over; for many birds, this is the ideal time to molt their feathers. Molting is the process by which birds replace their current feathers with new ones. Feathers are not alive; they are made of keratin, the same as human fingernails or hair, and therefore are completely replaced rather than healed when they are damaged. Molting serves many purposes: to replace worn out feathers that have become too old, to revert from flamboyant breeding plumage back to dull-colored “basic” plumage, and replace juvenile feathers with mature ones. This is a very energy-intensive process, so it makes sense for it to occur during more restful times of the year.
Different birds molt at different times, some once a year and some more often. This is based on the age, sex and even habitat of the bird in question. Some birds can acquire adult plumage in one year, where others take years to reach sexual maturity. Of course, no bird can molt all of its feathers at one time - it would be bald and flightless! Rather, birds molt some or all of their feathers gradually over time. Since so many birds are shedding their old feathers, now is the perfect time to conduct a feather study on your backyard bird friends.
Many common feeder birds, such a goldfinches and sparrows, will be dropping their feathers in your yard. Since feathers typically comprise about 15-20% of a bird’s weight, you can be sure that they have a lot to lose! Collect those that you find on the ground and use them to learn more about feathers and flight with your child. Strive for a mix of downy and more structured feathers if you can find them. Don’t have a yard or can’t find any feathers? Purchase some at the craft store; even though they are dyed, they are still real bird feathers and will work for this study.
For this study, you will need: flight feather, contour feather, down feather, ruler, binoculars (optional) and magnifying glass.
1. Feather observation: Lay out your feathers on a table and do a thorough initial observation. How are these different types of feathers similar? How are they different? Measure each one with a ruler – which is bigger and which is smaller? Use each to fan your face and observe how it feels – which ones move the air? What is the color and shape of each feather? Is it damaged? If so, what do you think happened to it?
2. Flight feathers: Flight feathers are perhaps the ones that we most commonly see on the ground. This feather has a hollow, central tube called a “shaft”; it runs down the length of the feather. There is also a broad, flat bit of feather along each side of the shaft that is called a “vane”. How does this feather look to you? Run your finger from the bottom of the vane to the top, noting how smooth it feels. This vane is composed of little individual barbs that resemble skinny hairs coming off of the shaft. Each of these barbs has tiny hooks along its length that zip together to form the vane. Run your finger from the top of the feather to the bottom, breaking apart the smooth vane and exposing the barbs to view. Using a magnifying glass, look for the hooks along the barbs. Now smooth the barbs back together by running your fingers up the feather. This action is similar to the act of preening, in which birds smooth out their feathers and groom them.
3. Down feathers: Down feathers look like what you would find inside of a pillow. They are small and fluffy. Feel the feather. Can you preen it with your fingers into a single vane? Why or why not? The barbs on these feathers lack hooks, making them fluffy rather than structured. Down feathers are used for insulating the bird; the fluff created by each feather creates an air pocket against the bird’s body, which keeps in heat and allows the bird to maintain a comfortable body temperature.
4. Contour feathers: Contour feathers look like a cross between a down and a flight feather. This feather is smooth at the top, made of a small vane with barbs that form a triangle-like shape. The bottom of the feather is fluffy, called “pennaceous”. Feel both parts of the feather. What use to do you think it had for the bird? These make up the majority of a bird’s feathers; they provide most of the bird’s patterning and coloration, as well as cover the bird to protect its sensitive skin and give it an aerodynamic shape. Contour feathers overlap each other on a bird’s body like shingles.
5. Bird watching: If you have binoculars, watch some birds out your window and notice the feathers on their bodies. Notice how they are attached in patterns. Can you see the shingle pattern of the contour feather on their bodies? Do you see how the flight feathers are arranged on the wings? Do you see any birds that look like they are fluffing out their feathers? They are pushing air into the spaces between their down. What else do you notice about the birds that you are watching? Look for interesting behaviors; watch them eat and interact with each other.
A feather study is a fun way to get your child interested in birds and how they fly. If you want to watch the birds in your yard more regularly, consider putting up a bird feeder close to your window and investing in a pair of binoculars. Bird watching is a rewarding hobby for many people, even children, and a great way to connect them to the nature in your backyard. Birds are visible, beautiful and often very funny - they the best backyard critter with which to make a real connection. Consider making bird watching a family activity!
To learn more about birds and bird behavior, check out the Cornell Lab of Ornithology. Check out this article to read more about molting.
To read more about connecting with backyard critters, check out our post “Who Lives in Your Yard“.
To learn more about feathers in general, check out the excellent book, Bird Feathers by S. David Scott and Casey MacFarland.
The above photos were taken by Cory Doman, photography intern.