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While at rehab, I watched out the window as a robin was building a nest. The female continually carried nesting materials that she placed at the nest site. Every so often she would sit in the nest to make sure it would be in the familiar circular shape.
Although the male was close at hand, he appeared to be getting in the way instead of helping.
Later in the day, I watched a black-capped chickadee checking out one of the bird houses in our back yard. This reminded me that I needed to clean out the birdhouses so they would be ready for another nesting year.
Many birds have begun to build their nests. This nest building is the best time to observe our feather friends.
Etymologically, a nest is a place for sitting down. It is a very ancient word, and its history is traced back to the Indo-European word nizdo, which was formed from two words: ni, meaning down and sed, meaning set. Our word neat is a derivative of the French word net, which means nest.
A bird's nest is its home and where it raises the family. It is usually thought of as the familiar bowl like structure of a robin's nest that is built of grasses, twigs, and mud; however, a bird's nest is not only built of materials. A nest can simply be a spot or place in the bird's chosen habitat.
Some birds lay their eggs without any nesting materials on bare rocks. For example, vultures lay their eggs in logs or on the floors of abandoned buildings; whip-poor-wills use the leafy forest floor and night hawks lay their eggs on bare ground or on the flat roofs of buildings.
The most highly specialized nest builders are the songbirds (passerines) that build complex nests. The hummingbirds, which are not classified as songbirds but rather in the order of Apodiformes, are an exception because they build exquisite nests.
A bird usually builds its nest in an inconspicuous place, which is hidden and camouflaged by its materials, to hide the parent bird while incubating the eggs, and to protect the eggs, or young, from predators.
Birds that build their nests in trees are known as altricial birds. Their young, which hatch out in a relatively short time, are born blind, featherless and need to stay in the nest for several weeks. Their nest is the protective nursery in which the young are given warmth and also food brought to them by their parents.
It's a place where the young birds begin to develop their learned and instinctive responses to the world. Here they achieve their growth to the time that they can flutter or fly away from the nest.
Birds, such as turkeys, grouse and pheasants, that nest on the ground are known as precocial birds. Their incubation period is much longer than altricial birds. The young of precocial birds are fully developed when hatched. Within hours, these birds leave the nest and never return.
The young follow the female who will lead them to food, and here they feed themselves. There are some exceptions to these two rules: for example, the wood duck is a precocial bird but is a tree nester.
The eggs of the precocial birds are larger, the reason being the egg must contain more nutritive materials (yolk and albumen). Since the young hatch out fully developed (with full stomachs) they do not need to eat for several hours, while the eggs of the altricial group can be smaller because the young are not fully developed and must be fed almost immediately after hatching.
Often the selection of the nest site is made due to its inaccessibility, such as rock cliffs, islands, tree branch tips, holes in trees or burrows in the ground. There have been reports of medium-sized birds finding protection by building their nests in the lower parts of larger predatory birds' nests.
Grackles and sparrows have been known to nest below osprey nests. This provides protection and scraps of leftover food. In South America, there is a bird known as the cacique that builds its nest around a wasp's nest. Although the wasps ignore the birds, they do attack people and animals that come too close.
Nest protection is simply done by the aggressiveness of the parents. Birds that nest in colonies can rout intruders by mobbing them. I've seen male red-winged blackbirds attacking cows, and I have been chased several times because I came too close to their nests. Great-horned owls, hawks and other large birds have been known to attack humans, sometimes inflicting injuries, because they came too close to their nest sites.
Eagles and hawks return to the same nests every year. they add fresh sticks to the rim. Some of these nests have been continuously occupied by eagles for years. One bald eagle's nest in Florida grew to be 20 feet deep and 9 1/2 feet across. The great-horned owl does not build a nest but takes over old nests of hawks, crows and even squirrels.
In the spring, when birds start to stake out their territories and begin building nests, I would get many complaints (even from Mary Alice) about birds repeatedly flying into windows. The bird, which would see its reflection in the glass, thinks another bird is trying to invade its territory and tries to drive it away. This can sometimes be fatal to the bird. If you have this problem, try to cut down on the glare of the glass so the bird does not see its reflection.
Hanging a plastic great-horned owl or crow outside the window could also help, however, these decoys should be moved frequently since the birds will get wise to this trick.
In the bird world, most birds go from egg to adult in a period of 4-6 weeks, at which time they are on their own. Compare this to humans, which could take 21 years or more. We are all aware that being a parent is a lifetime commitment. Even when our children are grown and out on their own, we still worry, while birds and animals protect and raise their young but there appears to be no bonding after they leave.
Bill Bower is a retired Pennsylvania Game Commission Wildlife Officer. Read his blog and listen to his podcasts on the outdoors at www.onemaningreen.com.