Beaks and Bills
by Joe Meche
April has come and gone and the arrival of May in the Northwest means that we’re surrounded by nesting birds. Although larger birds like bald eagles, owls, and great blue herons have been at it for a while, the smaller species are hard at work keeping their dreams alive. Bird nests are often overlooked as far as the general concept goes, but there’s far more to it than meets the eye. They are true architectural wonders when you consider that each species has different needs and all of the work is done with their beaks or bills and their feet. Try building something as ingenious and practical as a bird nest and you’ll see how dependent we are on our hands to get anything done.
photo by Joe Meche
Anna’s hummingbird nest
There has been much speculation as to the origins of nest building but many agree that birds adapted to the shortage of natural nesting cavities and created their own methods to shelter their eggs and subsequent young. Through another example of adaptive evolution, each species found methods and construction techniques to suit their individual needs.
Bird nests come in a variety of sizes and shapes. In fact, there are seven different types of nests that birds utilize to lay their eggs and nurture the young from the time of incubation and hatching to fledging. In each type of nest, no matter the size or species, there will always be a focus on the placement and protection of the eggs throughout the process. Evolution and instinct guide each species to create the ideal nest.
The most basic type of nest is a simple scrape, whether it’s on a sandy beach or gravel bar. The adults use their feet to hollow out a basic cup shape to hold the eggs in place. The resulting young birds are generally precocial and are ready to walk almost immediately after hatching. Two of the more reliable and local nesting species that utilize the scrape nest are the Caspian terns and killdeer. We all know the story of the large nesting colony of terns that was very successful in 2010 on the waterfront. That remarkable story ended, however, when they were unceremoniously evicted from the site by the Port of Bellingham.
Killdeer, on the other hand, continue to find places here and there for their simple scrape, whether in the beauty bark next to a local business or a gravel parking lot in the middle of nowhere. This species is the most numerous member of the plover family in North America and their simple taste in nesting sites accounts for their widespread numbers. With their distinctive calls, it was one of the first birds I learned away from our own backyard when I was growing up.
Burrowing owls are not common west of the Cascades, but we do have a few burrowing species that are easy to find and observe. Soft, sandy banks and cliff faces attract belted kingfishers and pigeon guillemots, as well as rough-winged and bank swallows. Although, I have observed guillemots nesting in storm drains in Oregon and on hollowed-out pilings on the waterfront in Blaine.
Cavity nesting birds include woodpeckers, several species of waterfowl like wood ducks and hooded mergansers, saw-whet owls, and roughly 23 pecent of passerine species. Cavity nests not only provide protection from predators but also from harsh weather during the sensitive time between the hatching and fledging of the young birds. From a human point of view, a cavity nest seems like a cozy start for a young bird.
The wide-ranging and numerous passerine species employ a number of designs to suit their needs. Only one-quarter of the species uses holes or builds elaborate structures while the remaining three quarters of the 450 species have open nests. One theory is that larger birds have a tendency to take over suitable cavities and simply enlarge the entrance holes. The larger entrance makes the smaller birds and their off spring more susceptible to nest predators like European starlings and nest parasites like brown-headed cowbirds.
Larger birds such as great blue herons, eagles, hawks, and ospreys make effective use of stable platforms or stick nests to raise their young. These nests have to be large enough to accommodate the young which will be about the same size as the adults before they fledge. These nests are usually made of sticks and added onto every year as there is a certain amount of site loyalty in suitable locations. The best examples are the bald eagle nests that abound throughout the county. These often huge nests are especially obvious during the winter months when deciduous trees have lost their leaves.
Locally, bushtits and Bullock’s orioles are two species that are known for their intricately designed pendant nests. If you’re fortunate enough to find a pair of nesting bushtits, take time to observe and enjoy the dynamic energy of two of our smallest birds taking to the task at hand. You will marvel at their teamwork as they’re driven to create their own version of a perfect space to lay their eggs. The cup where the eggs rest sits in the bottom of the hanging nest and the entry is located near the top …another example of the wonders of avian architecture.
Of all the families of birds, the swallows have diverse nests that don’t really fit together. Tree swallows and violet-green swallows nest in natural tree cavities, woodpecker holes, or manmade nesting boxes. Cliff swallows build their nests completely out of mud they gather from nearby mud holes in a most impressive example of nest building. Barn swallows use mud and straw to attach their nests to any available surface they can find. Roughwinged and bank swallows burrow into sand banks to lay their eggs. The largest member of the family, the purple martin, has adapted well to man-made structures that fit their needs.
Deforestation has created a shortage of suitable nesting sites for many smaller birds, so humans have stepped in by providing alternatives like nesting boxes and platforms to help alleviate the problem birds have in finding suitable nesting sites … likely problems that we created in the first place. In March, I built 130 nesting box kits for kids to assemble at the birding festival in Blaine. More than 100 of the kits left with kids who were excited to attract birds to their yards … maybe fostering a lifetime of ornithological pursuits.
A new platform was installed near Marine Park in Fairhaven to attract ospreys … a successful practice that has become widespread across the country. It wasn’t used last year, but we’re crossing our fingers this year. Ospreys have nested before on the waterfront near the end of Cornwall Avenue and even attempted to nest atop a large crane in one of the Fairhaven shipyards. That, of course, didn’t sit well with the owners of the crane, so that was the motivation for the new platform.
Regardless of the species and the specific nests they build, we can always picture a perfectly rounded cup shape designed to hold the eggs in place. From the small nests of our local Anna’s and rufous hummingbirds to the huge, weighty structures of bald eagles, the diversity of avian nests is one of nature’s true wonders. If you’re fortunate enough to find a nest, no matter the species, remember to be respectful of the process and give them lots of elbow room.
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Joe Meche is a past president of the North Cascades Audubon Society and was a member of the board of directors for 20 years. He has been watching birds for more than 60 years and photographing birds and landscapes for more than 40 years. He has written over 200 columns for Whatcom Watch.
