Florida Bird Egg Identification

Function

• Reproduction among birds produces one or more eggs, which are cared for by one adult---or sometimes both adults---until incubation is complete and hatching occurs. The egg consists of four main parts: the yolk, albumen, shell membrane and shell. The yolk is the yellow part of the egg and is the food supply for the developing bird. It is made of protein, lipids and water. The albumin is the clear part on the inside of the egg that serves as the egg's water supply and shock absorber. It is mostly water and some protein. The shell membrane protects the egg from bacterial invasion and evaporation. The final shell is the ultimate protection for the embryo.

Color

• Eggs vary widely in color, which may depend on where the egg is laid. Eggs may be white or colored. White eggs occur because the birds that lay them use special nests that are dark and enclosed, or lay the eggs in dark places such as holes in trees. Colored eggs occur because of pigment added in the uterine region of the genital tract while the egg is being laid. The pigment comes from blood: reds, browns and blacks from hemoglobin and blues and greens from bile pigments. The colors of the eggs provide camouflage in the natural environments in which birds are found.

Shape and Size

• There are several variations in egg shape and size that are found in Florida. Round, ball-shaped eggs are common to owls and woodpeckers; round, pointy eggs are produced by plovers; birds with a narrow pelvis that need to lay large eggs tend to lay longer eggs that will fit through their pelvis. Oval-shaped eggs, which are the most common, are laid by chickens. The thickness of eggs also varies. Wading birds that would live in wetlands such as the Everglades are known for their thin shells.

Examples

• Florida is home to hundreds of species of birds, including starlings, robins, blue jays, hummingbirds, brown pelicans and sandill cranes.
  Starlings lay four to six eggs at a time, each 1 1/8 inches by 3/16 inch. The eggs are white, pale blue or green. Robins lay four eggs that are 1 1/8 by 3/4 and pastel blue. Blue jays lay four or five eggs that are 1 1/8 by 13/16 and pale olive with dark spots. Hummingbirds lay two eggs the size of a pea or jellybean and are white. Brown pelicans lay two or three eggs, 3 1/8 by 2 1/8, that are white and lightly spotted. Sandhill cranes lay two or three 4-by-2 1/2 eggs that are white with dark brown spots.

Florida Tours

• A birding tour is a good way to get a look at bird eggs in Florida, which has many species of birds not found anywhere else in the United States or even in North America. There are many tours offered, including those that go through the Everglades to see pelicans, egrets, shorebirds and gulls to name a few. There are also tours that go through the Loxahatchee National Wildlife Refuge to see the eggs of herons, egrets and ibis and tours to the Florida Keys to observe large populations of macaws and parakeets.