Nests and Eggs of American Birds

1. What they did

Ernest Ingersoll, a former zoologist of the United States Geological Survey, wrote this book in parts in 1879 and 1880 for egg collectors and young naturalists. At the time there was no American book for identifying birds’ eggs. He set out to bring together the scattered records of how North American birds breed, adding his own observations and notes sent to him by other naturalists.

For each species the book aims to give:

• Where the bird breeds and when it arrives in spring.
• The nest: the site chosen, the materials and how the nest is built, and features for recognising it.
• The eggs: when laid, how many, their size and markings, illustrated on colour plates.
• Incubation and the young: how long the birds sit, what the young are fed, and how the parents care for them.

This copy covers about 100 species, from the thrushes (starting with the American robin) through the wrens, larks and pipits to the wood warblers, with 14 plates of eggs.

2. What they found

The book is a natural history rather than a study with results. Some examples of what it reports:

• Robins nest almost anywhere: in orchard trees, on fence rails, pillars, ledges, inside a well, and once on the ribs of a fossil skeleton in a college museum. The female builds with mud pressed into shape with her feet and breast, lets each layer dry, and lines the nest with soft grass. Nests are about 4 inches across inside and 2 inches deep. The four or five blue-green eggs average 1.10 by 0.80 inches; incubation takes 12 to 14 days, and the young stay in the nest 10 to 15 days more. Two, and in older birds often three, broods are raised.
• Site fidelity: a robin observed by Mary Treat nested on the same piazza pillars and the same oak for three years, building a second and then a third storey on the old oak nest.
• Wood thrushes build on a foundation of dead leaves, 6 to 40 feet up, and both sexes build for five or six days.
• American dippers build domed balls of moss beside fast water, once behind a waterfall where the outside stayed wet with spray. One observer saw a dipper shake water from its feathers over the nest, which he took to be keeping the moss green and growing.
• Black-capped chickadees hide their nests so well that Ingersoll never found one. John Burroughs found one only after a boy hid by the tree and watched where the parents carrying food went.
• Horned larks in Labrador nest in moss that matches the sitting bird; when disturbed, the female flutters away feigning lameness, and the male joins in.
• House wrens nest in all kinds of places near people (an old hat, the skull of an ox, a coat sleeve, the box of a doctor’s gig) and will drag out the nests of bluebirds and martins to take over the site.
• Long-billed marsh wrens build extra nests that are never used. Observers offered different explanations: nests abandoned when found by enemies, or decoys to throw an enemy “off the track”.
• Ovenbirds build a domed nest on the woodland floor from the materials around it, so it blends in. Ingersoll suggests the roof guards against the eyes of enemies rather than the weather, since nests sheltered by rocks or roots are often left open.

3. What they concluded

The book does not draw general conclusions. The prospectus states that, when all recorded observations are brought together, much more is known about the breeding of North American birds than readers might expect, and that the nesting season is a part of bird life that earlier bird books had touched on only in passing.

6. Other technologies, skills or innovations

• Lithographic colour plates of eggs, drawn from typical specimens in public and private collections, and wood-cuts of nests.
• Practical clues to finding nests are scattered through the text, for example watching parents carrying food, waiting quietly at a distance, and searching the ground slowly where a nest is suspected or flushing the bird.