I was looking out the coffee room window at work recently and noticed a bunch of House Sparrows hopping around on the ground. At first I thought that they were just looking for food but then I realized that they were actually foraging for nesting materials.
It was fascinating to watch these little birds busily pick away at the grass and twigs and evaluate the material they were gathering. One little bird picked up a fairly large twig and tried a number of times to fly off with it. However, it was either to unwieldly or too heavy to be managed in flight so finally the bird gave up and went off looking for something else. Each bird that was there flew off in different directions so I expect we will have a number of different nests around the seed plant this summer. However, all this activity got me thinking about bird nest building and how interesting it is.
Nests vary by bird species: When I got looking into nest building I found it quite interesting to discover that the nests vary greatly between bird species.
For example, an American Goldfinch nest can be found just above ground level to several meters above ground level in the shady dense canopy of a bush or tree. The nest itself starts out with twigs connected by spider silk. Then small roots and plant materials are added to the nest cup and finally the nest is lined with plant material that is "downy" in texture.
On the other hand, a Robin's nest is usually 3 - 7 meters from the ground in deciduous or conifer trees. It is an open cup of grass or twigs that are glued together with a thick layer of mud and lined with grass. So it appears that nests are as individual as the birds who build them.
A great resource site for information on different types of nest is NestWatch at the Cornell Lab of Ornithology. There you can find information on the nests of many of the more common backyard birds and also join up and provide data on your own nest observations.
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