Eggs found in the wild can come in a surprising array of shapes, sizes and colors. Usually they are able to tell a person which type of bird laid the egg as well as other factors. Depending on the environment and part of the country, a wide variety of birds can be found in a given area.
Bird Egg Identification Guide
The eastern bluebird's eggs are a soft or slate blue color, though they are also sometimes nearly white They have a smooth surface texture, and are only a little larger than an American dime. Their shape falls into the category of "subelliptical." These eggs are found in nests that the bluebird weaves from grass or pine needles.
The shells of the black-capped chickadee are extraordinarily thin. They are often white or cream colored with periodical spots, blotches, dots or speckles. These speckles vary in range from a brown or red to black, and can most often be found on the more bulbous portion or wider end of the egg. These eggs can be found in nests that are mossy in texture that are closed in with fur or soft plant fibers. This covering or "plug" is put in place by the female to protect the eggs in her absence.
These eggs are oval shaped, and are often granulated and glossy, with the occasional red or brown blotches on the bulbous end. Variations of this species such as the bronzed cowbird, have eggs that are teal or aquamarine and have no markings whatsoever. The ultimate in deadbeat parents, these birds do not build nests, but instead lay their eggs in the nests of other birds and have these "adoptive parents" warm and feed their young.
The eggs of the ash-throated flycatcher are oval. They range in color from cream to milk, white or pink. They are frequently marked with either thick or thin streaks of dark color as well as blotches of brown, purple or gray. These eggs are found in nests that are disorganized, lying around grasslands and dry animal dung.
These species are not native to the United States, and are not protected by law. For this reason they are not recommended to be kept in your nestbox. These eggs are creamy, white, gray or light green. The shell is smooth and glossy. Sometimes they come with spots and different thicknesses. These nests are also disorganized and come with a wide variety of items included in them such as grass, cloth, feathers, cigarettes and vegetation.