Bird Nests

Winter is quickly turning into spring in our area.  Freezing temperatures that were here just two weeks ago have passed, and daytime temperatures are warm with temperatures often  staying above freezing overnight.  In the local bird communities, we are beginning to hear males singing for mates.  This will begin the cycle of courtship, mating, nest building and raising a new family.

As birds evolved from cold-blooded to warm-blooded animals several million years ago, they started to build nests to help keep their eggs warm.  Researchers think that the first nests were simple piles of twigs on the ground in depressions or among rocky or sheltered areas.  The first nests built off the ground were also made from loosely arranged twigs.  There are species today who still use both of these types of nests.

Nests have several functions.  They create a place to hide and guard the eggs from predators.  They  provide protection for the parent who remains with the eggs while incubation takes place.  They create a place where incubation is easier in variable weather conditions.  Eggs can be kept warmer and out of the wind and rain.  Many nests are built in places that are already sheltered, such as lower branches of trees where wind effects are less, under large limbs or next to tree trunks that provide protection from both wind and rain.  In urban areas, as well as woodlands containing a heavy shrub layer, most nests are less than ten feet off the ground.  The most complex nest construction is that of a cup nest, built of mud and grass, in a tree fork or hanging from a branch or plastered to the side of a building.

Robins build a cup nest of twigs and mud in the fork of a tree or on a horizontal branch close to the trunk.  Sparrows, of all species, make small cups of grass built either on or near the ground.  Goldfinches build a small nest lined with soft milkweed or grasses in the crotch of a tree. Hairy and downy woodpeckers, like all woodpeckers, prefer holes in trees.  Hairy woodpeckers will drill an oval-shaped hole in a dead branch of a living tree, while downy woodpeckers drill a perfect circle in a branch of a dead tree.  Most woodpecker holes face east or south under a branch to gather warmth from the sun and protection from the rain.  Geese build a large nest on the ground near water, typically lined with down for warmth and comfort. 

Finding nests in late spring and throughout the summer can be quite difficult.  You may try to follow a bird back to its nest, but many nests are only built by one partner, and you could follow the wrong one  and be disappointed.  Many birds will build a nest in one place, but will forage for food in an entirely different location.  If you should walk near a nest, birds will sing or make a display to distract you.  Getting out at this time of the year lets you see where many of last year’s nests were located.  Take a walk before leaves are out and see how many nests you can still find from last year.

Want to learn more?  There are many field guides that will have information on building nests and nesting behaviors.  You may want to consider a specialty volume such as “Eastern Bird Nests” by Peterson Field Guides for explicit information on nests of all kinds.