Nests varied as the birds that build them
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Breeding season for birds means nest building and egg laying. While the birds themselves are beautiful and fascinating, their nests are also interesting.
Some are classic, some are almost unrecognizable, and others are dramatic.
Nest types found through Southern Ontario can be put into several groups including tree nests, ground nests, cavity nests, and building nests.
Classic cup-shaped tree nests are built by many warblers as well as species such as robins and ruby-throated hummingbirds. As an example, the American robin's nest is fashioned from twigs, grass, moss, and rootlets that are held together with mud. The nests are lined with softer dry grasses.
A unique tree nest is built by the Baltimore oriole. A sac-like pouch that hangs down from a branch is woven by the female oriole. It is made from grasses and other materials that might include strips of bark, wool, or hair. The bird pokes at the materials as they are being woven to create knot-like tangles for support.
There are many ground nesting birds. Gulls and terns are included in this group.
KILLDEER
A killdeer is also a ground nesting species. This bird will find or make a depression in bare ground that is 8 or 9 cm across. It is often difficult to recognize these nests because they blend in to their surroundings so well.
Canada geese will also nest on the ground. Like many species, however, they are adaptable. Cavity nesting birds include wood ducks, screech owls, Eastern bluebirds, tree swallows and purple martins. Many of these species welcome man-made cavities such as nesting boxes.
Bird houses are also essentially cavity-type nests. A Goderich birder shared photographs with me earlier in the month of a house wren settling into one of her backyard bird houses.
Some birds such as bank swallows burrow to create a nest that protects them from predators and the elements.
A good number of species have adapted successfully to the built environments around them. Barn swallows frequently make nests on the sides of buildings from mud pellets. Peregrine falcons will nest on tall buildings that double as cliffs. Robins too will sometimes build a nest on a structure.
Although ospreys are generally thought of as tree nesters, London birders can see several osprey nests on towers.
Many species will reuse a nest from a previous year in one way or another. Ospreys will return to the same nest used in a previous year. Baltimore orioles will reuse material from a previous year's nest.
The ruby-throated hummingbird's nest is the smallest bird nest in Southwestern Ontario. The largest nests in the area are those of the bald eagle. These are massive constructions.
Interestingly, some species don't build nests. Brown-headed cowbirds, for example, are notorious for laying their eggs in nests of other birds and letting the host do the work. They will lay eggs in the nests of any number of species including yellow warblers.
Like the birds themselves, nests are protected by law and should be left alone. There are provisions of the federal Migratory Birds Convention Act that protect the nests and eggs of birds. Keep a distance from nests when observing them.
Paul Nicholson can be reached at g.paul.nicholson@gmail.com Twitter @NicholsonNature
KILLDEERS
Per Nielsen
QMI AGENCY
The killdeer is primarily known as a shore bird but they can be found far from water at times.
They primarily eat insects. During our winters they head south to Central America and then return with the warmer weather.
The interesting thing about killdeer is that they will do a “fake broken wing” display to distract predators from their nests which are usually found on the ground. The adult bird will walk leading away from the nest. It will usually droop one wing as if it were broken then flop on the ground pretending to be injured and making the predator think it has easy prey. Once far enough away from the nest the killdeer will simply fly off.