Birds show extraordinary variety and ingenuity in the nests they build. An untidy mound of sticks, simply dropped on top of one another, is all that a mute swan requires. House martins, on the other hand, literally build their homes. They skim over puddles and ponds, picking up little pieces of mud, which are built up into round-walled structures on the sides of buildings. Cuckoos, of course, are renowned for the fact that they use other birds’ nests in which to lay their eggs. They are able to mimic the size, shape and colour of the host-bird’s eggs to some extent, so that the additional egg is not immediately obvious.
It should come as no surprise that hummingbirds, our smallest birds, make the smallest nests. Hummingbirds build on top of tree branches, using plants, soft materials and spider webs. Ruby-throats decorate theirs with flakes of lichen. Anna’s hummingbirds may lay eggs before a nest is completed, continuing to build the sidewalls during incubation. Most impressive is how these nests stretch. Hummingbirds usually lay a pair of eggs the size of black beans inside a nest about the diameter of a quarter. As the babies grow, the nest expands, keeping things tight and cozy.
Orioles are the seamstresses of the bird world. Their iconic pendant nests dangle from outermost tree branches. The nests are impossible to miss among the barren winter branches and nearly as impossible to spot, surrounded by leaves, during the breeding season. Orioles use whatever material is available to stitch their bag nests: long grasses, twine, even horsehair. The nests are lined with soft materials such as plant fibers, feathers or animal wool. The Altamira oriole of extreme south Texas and Central America constructs one of the longest dangling nests, which can hang down more than 2 feet.
It’s the exception rather than the rule, but a few species of birds get away with building hardly any nest at all! This doesn’t mean they are haphazard in their approach to laying eggs, though. Beach nesting birds (including black skimmers, many species of terns, and piping, Wilson’s and other plovers) lay eggs in shallow depressions scraped out in the sand. The remarkable thing about the eggs of these species is their cryptic camouflage coloration. Eggs are often speckles and match the sandy granules of the makeshift nests. Sometimes these birds will line the shallow scrape with shells or sand to add to the camouflage. As beaches get more developed, some of these beach nests have adapted to laying eggs on nearby rooftops.
Huge colonies of murres and guillemots nest on rocky coastal cliffs. Most lack any structural nests, instead laying eggs that are extra pointy on one end. This shape helps the eggs pivot around the point instead of rolling over the edge. These ledge nesting sites are also more protected from predators. Cliff nesters aren’t found only on coasts. Lots of species, including condors, ravens and falcons, use cliffs, but they build stick nests in the crevices.
Some waterbirds, including many ducks, nest in upland grasslands far from water. Others, such as loons, grebes, coots and gallinules, nest directly on top of the water. Eggs will sink, so the birds build floating platform nests out of cattails, reeds, other aquatic vegetation, or mud. They anchor the nests to emergent vegetation to conceal them and to keep them from drifting away.
Holes in trees and cacti are nest cavities; underground nests are burrows. Burrowing owls in Florida will sometimes dig their own burrow, while the burrowing owls in the west usually rely on spots excavated by prairie dogs, badgers, tortoises or other diggers. Other underground nesters include bank swallows, belted kingfishers and Atlantic puffins.
It is hard to say officially whoop lays the first eggs each year, but my pick for favorite nest is the great horned owls. Sure, many species can begin nesting in January in southern states, but it is still winter in the nothern states when great horned owls start incubating their eggs in nests made of sticks, often in trees. It’s essential that these owls get an early state on nesting, because the species is slow to hatch and fledge. It is remarkable to think of the owls sitting on eggs as snow piles up during frigid nights.
The grand champion nest-builder is… the bald eagle! In 1963, an eagle’s nest near St. Petersburg, Florida, was declared the largest at nearly 10 feet wide, 20 feet deep and over 4,400 pounds. That nest was extreme; most bald eagle nests are 5 to 6 feet in diameter and 2 to 4 feet tall. Nest construction can take three months. Eagles typically use the same nest year after year, adding to it each season.
Picture Credit : Google