What do you think of when you hear “bird’s nest”?
Most of us probably think of a cup-shaped nest built with twigs. Cup nests are one style of nest, but nests come in an array of sizes, shapes and materials that parallel the vast variety of birds.
We have an amazing variety of birds that nest in the Pacific Northwest, and this is the time of year many species have built nests, or spruced up an old one. From birds who spend most of their lives on the water, such as the pelagic cormorant, to birds whose feet may never touch the ground, like Vaux’s swifts, all of our local summer birds have nests.
Each species has a nesting strategy that works for its lifestyle, location, size and the materials available. Each bird that builds and maintains a nest is a proficient engineer. Some of the engineers have more challenging tasks ahead of them than others.
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How small can they go?
Building a nest takes a tremendous amount of energy and attention, both of which are important for bird survival. Think about all of the trips back and forth a bird must make to construct a nest. After locating a good place to put their nest, they must find nest material, carry it to the nest site and build the nest, one piece at a time. When birds are building a nest, they burn energy and time, and are more vulnerable to predators and accidents. And while they are building, competitors can invade their territory.
To conserve resources, birds generally create nests that are as small as possible. This not only saves on energy from a construction and maintenance standpoint, it creates a smaller, warmer microenvironment that makes it easier to keep incubating eggs and new nestlings warm and dry.
The bare minimum
There are species that don’t construct nests. Rather, they use locations already suitable for nesting. For example, peregrine falcons often use cliff ledges, where they don’t do much more than scrape away some of the top material to make a small depression for their eggs. Sometimes they use a stick nest left behind by another large bird, and just lay their eggs on top of the already-built nest. Peregrines are nest minimalists and don’t build anything of their own. It’s up to these birds to find a nest location ready to go.
Now these are engineers
Other local birds build quietly extravagant nests. Anna’s hummingbirds use such materials as moss, lichen and cattail “fluff,” and weave it together with spider web. These amazing, tiny architectural wonders aren’t large enough to fully hold one of the parents, but they are snug and warm for tiny eggs and nestlings.
Bushtits are small, social songbirds that utilize helpers, often adult males, to raise their young. These helpers, the parents and the young all sleep in the nest during the breeding season, so the nest they make has to be large enough to fit the entire family. Bushtits are about 3 inches long, but the long, pendulous nest they build hangs down at least a foot from the branch it’s attached to. It takes about a month for them to engineer this palace made from vegetation, insulated with fur, feathers or other material, and held together with spider web. Bushtits often have two broods of young in a breeding season and use the same nest for both.
Another year with the fixer upper
Some species use the same nest from year to year, and do whatever maintenance is needed for the nest to function. Bald eagles and osprey work long and hard on building a nest from scratch. They use many large sticks to build a nest strong enough to hold two adults and young that get quite large. The investment pays off in the long run, because the nests can generally be used over and over through the years, with minimal updates.
So keep your eyes open as spring unfolds. You could very well see birds engineering their nests. If you find a nest, please only observe. Don’t touch or try to peek into nests. You could disrupt them and ruin the chances of the nest being successful. But watch what happens, and you will be enchanted and amazed!
Check out some nests
▪ Some bird nests are obvious, while others are so hidden they are almost impossible to see. A good place to start is web cams. The internet has lots of bird nest cams that let you pick a species and watch the action.
▪ To see nests in person, visit a ferry dock. Take a close look at the “bumpers” near the docks. They are often full of nesting cormorants this time of year. Osprey often nest near the water by the Chambers Bay meadow. Look for a big stick nest if you are taking a walk by the bay.
Another strategy is to sit quietly in a park and watch. Morning and evening are the best times. Where there are birds this time of year, there are bird nests and babies who have left the nest. Watch birds as they are out finding food. Are they heading back to a nest full of babies in the trees?