Bird Nests in Whatcom County

Joe Meche is a member of the board of directors of the North Cascades Audubon Society and is in his eighth year as editor of the chapter newsletter. Joe is also a member of the board of directors of the Washington Brant Foundation. He has been photographing birds and landscapes for over 30 years and has been watching birds for more than 50 years.

Have you ever stopped to consider the process involved in building a temporary home to raise a family? Have you given any thought to the difference between the size of an eagle’s nest versus the size of a hummingbird’s nest? It’s obvious just by the size of the two birds that there has to be a difference. The range of nest sizes and designs is almost as varied as the number of bird species. With these basic thoughts as a foreword, it’s time we had a look into the place where all birds begin their lives—the nest.

Unlike most other animals, birds do not give birth to live young. Birds lay eggs, but before they do, they must create a place to hold and protect the eggs throughout the incubation process and until the young fledge. This basic process is not only a necessity for birds to procreate, but is also considered to be the single most demanding commitment of time and energy that a bird will ever make. In some species, both sexes are involved in many of the aspects of nest building and maintenance. Birds build nests because the very survival of their species depends on them to do so.

The basic design of each bird’s nest is the epitome of form and function for that particular species. Other factors that come into play are habitat and climate. The realtors’ mantra—location, location, location—applies to bird nests as well. Birds have some degree of control over habitat and many species migrate to their nesting areas when the climate is suitable, so protection from predators becomes the highest priority. According to noted naturalist Alexander F. Skutch, the main factors that contribute to nest safety are “invisibility, inaccessibility and impregnability.” Since the incubation of the eggs and protection of the nestlings are of utmost importance, nest construction and site selection reflect these priorities.

Cryptic coloration of some nesting birds and their eggs makes them practically invisible to potential predators. Nests on sheer cliffs and behind waterfalls, nests on floating platforms, and nests in deep burrows or cavities provide safety for the nests and the nestlings, as well as the incubating adults. Nest predation accounts for the highest percentage of breeding failure in most species.

Ground-nesting birds are more vulnerable than other species for obvious reasons, but colonial nesting has provided success for many ground-nesting seabirds. Colonial nesting has its drawbacks, however, in the increased competition for sites, nesting materials and food. Still, the perceived safety of numbers is usually sufficient to encourage large concentrations of birds to nest in a suitable area that also provides a rich source of food.

Nest building can be a joint effort of both male and female, as a part of courtship and pair bonding. Part of the courting process involves site selection and displays, along with the gathering of nesting materials. When the female is on the nest, especially during the incubation period, the male is at his territorial best to protect the female from other males and potential predators. As is the case with some waterfowl species, however, the male abandons the female when it comes to nesting time. Nest design, size and shape are dependent on the individual species, but all birds line their nests with various materials to keep the eggs warm and, in some cases, to serve as camouflage to confuse predators.

Locally, we can find a good cross-section of nests from a variety of species, ranging from our original pair, eagles and hummingbirds. In the case of raptors, such as bald eagles and red-tailed hawks, the stick nest is the type that is usually constructed. Some eagle nests in suitable habitats are added to year after year and become massive structures, lasting many generations. Look along lakes and streams, open fields and shorelines in winter to find their nests. Make note of the locations and monitor the nests during the breeding season as a citizen science project. Turn in your results to your local Audubon chapter for further dissemination.

Other local raptors can be found nesting in early spring. Ospreys make stick nests in the tops of snags near rivers and lakes but have adapted quite well to man-made nesting platforms. Northern Harriers break the mold of other members of the family Accipitridae by nesting on the ground. Likewise, in the family of owls, the short-eared owl nests on the ground while other family members nest in natural cavities in trees or cliffs or, in the case of barn owls, on platforms or beams in old barns. The northern saw-whet owl has become a frequent nester in man-made nesting boxes in the county.

Our largest and most recognizable wading bird—the great blue heron—builds a stick nest in trees. The new colony at Post Point on Bellingham’s Southside is growing and continues to be the focus of some contention between developers who wish to take advantage of the view property and environmental groups who wish to protect the property for the herons. Other, larger nesting colonies of these magnificent birds can be found at Point Roberts and along Haxton Way, on the Lummi Peninsula.

Local nesting waterfowl utilize nests made of available vegetation near water, although wood ducks and hooded mergansers will nest in man-made boxes or natural cavities in trees. Gulls can be found nesting on rooftops and marina breakwaters along with double-crested cormorants. Killdeer are local nesters that utilize a mere scrape on the ground for a nest. If you get too near a killdeer’s nest, you’ll probably be able to observe one of nature’s finest distraction displays, as the adult bird(s) try to lure you, a potential predator, away from the nest.

Most passerine species conform to what we usually expect when we think of bird nests. The simple cup-shaped nest is the norm with a few notable exceptions. Bullock’s orioles, bushtits and kinglets build pouch-like nests that can be found hanging from branches in suitable habitats. Chickadees, nuthatches and some wrens are cavity nesters and have been known to utilize nesting boxes. Red-winged blackbirds and marsh wrens build their nests in cattail wetlands.

Everyone knows that woodpeckers are the carpenters of the avian world since they build their own houses. The holes that woodpeckers excavate for their own nests are often used by other cavity nesters after they’ve been abandoned by the woodpeckers. Woodpecker holes provided the inspiration for many builders of nesting boxes, such as Homo sapiens.

No other group of birds displays as much diversity in nest building as the swallow family. The members of this family that nest locally are classic examples of this diversity. Tree and violet-green swallows are cavity nesters and seek holes in trees or man-made nesting boxes. Barn swallows build shelf nests underneath eaves, or on beams inside open barns and other structures. Northern rough-winged swallows nest in burrows or holes that they occasionally make in sand banks along streams, lakes and rivers. The most elaborate nest of all is that of the cliff swallow, which nests in dense colonies under bridges or under the eaves of houses and barns. This swallow is unique among birds in that its nest is constructed of pure mud.

Everything in the life of hummingbirds is in miniature, including their nests. Female hummingbirds build nests on the top of branches, using an assortment of fine materials such as hair, feathers, downy material, and even lint and carpet fibers. These materials are often held together by spider webs. Some nests have fine strips of bark or lichens on the outside that act as camouflage. Hummingbird nests are often reused and built upon in subsequent nesting seasons.

From eagles to hummingbirds, birds’ nests are engineering marvels that span an incredible range of diversity. In some cases, old nests are recycled but more often than not, new nests are built every year. Birds are driven to reproduce and, over thousands of years, have evolved as master builders of structures that enable them to protect their eggs and offspring from predators and the weather. If you can’t quite perceive the wonder of bird nests and you balk at small remodeling projects around the house, try to imagine building a new house every year—and then using it for only a few months. §