Bird Egg Identification

Bird Egg Identification
Whether walking through a forest or looking out your kitchen window, your bird-watching efforts can be enhanced when you learn to identify birds' eggs. Upon first glance, color might be the obvious characteristic, but size, shape, texture, the number of eggs in a nest and even the sheen of the shell can be just as important. Also, the type and location of nest can be indicators in arriving at a positive identification.


Difficulty: Easy

Things You’ll Need:
  • Binoculars
  • Bird identification field guide that includes bird eggs
Step 1
Walk in the woods, along a river or even in your backyard to look for nests. The best time to see eggs in nests is spring during breeding. Breeding season runs from about mid-March to August. Forked tree branches are the natural place to look, but don't ignore other potential habitats just because they might not seem like nesting places (after all, barn owls got their name for a reason). Since northern cardinals prefer thickets, look there for their cream-colored eggs with light brown speckles. Slight depressions along river banks and marshes could contain the oblong, off-white egg of a Canada goose.
Step 2
Consult your field guide. Eggs come in many different colors, ranging from white to black. Most eggs are a variation of off-white or cream, but some are yellow, blue, brown and even green. Take notice of any markings, whether the eggs are speckled, spotted, streaked or marbled. Look where these markings may be concentrated. For example, Carolina wren eggs tend to be more heavily flecked at the base than at the top. Next, look at the size and shape. Some eggs are more conical, peaked at the top with a wider base, like those of the killdeer, while some are more spherical, like the great horned owl's egg. Finally, examine the gloss and texture of the egg.
Step 3
Refine your search If two or more types of eggs appear similar. For example, both American robin eggs and those of the eastern bluebird are blue. The colors of these eggs can range from pale blue to medium blue, however, by knowing that robin's eggs are significantly larger and generally more conical than bluebird eggs, a more accurate identification can be made. Another aid in identifying eggs is the number per clutch. A Canada goose nest may contain two to eight eggs, while a clutch of mallard eggs might number over a dozen. Of course, nature has exceptions to every rule, so egg appearance, as well as the numbers of eggs of the same species, can vary from region to region.

Tips & Warnings

The Migratory Bird Treaty Act of 1918 prohibits the taking of eggs from nests of more than 800 different species of bird. Included on this list are some common backyard birds such as northern cardinal, blue jay, American robin, gray catbird, song sparrow, cedar waxwing, American goldfinch, tufted titmouse and white-breasted nuthatch.

Article Written By Paul Weidknecht

Paul Weidknecht’s non-fiction has appeared in "Outdoor Life," "Yale Anglers' Journal," "Fur-Fish-Game," "Snowy Egret," and elsewhere. His fiction has appeared in "Clapboard House," "Potomac Review" online, "Stone's Throw" magazine, "The Oklahoma Review," and "Freight Train" magazine. He lives in northwest New Jersey. He holds a Bachelor of Arts in psychology from Muhlenberg College.

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