I like to do a variety of topics for this column. I love backyard birds. Since moving to the country one of my greatest pleasures is feeding and watching my birds. I was reading in a birding magazine when I came across this interesting article on bird eggs. I wanted to share this information with my column followers.
Bird eggs range in many colors. They can be ornately covered with spots, blotches and scrawls. They vary in shape and size. They must be thick enough to withstand the weight of an incubating parent but thin enough to allow the embryo to break through and hatch. Other than heat and protection, all the resources needed for a chick to grow and mature are packaged up cleanly and tightly in the eggshell surrounding the growing chick. Egg color, size and incubation change from species to species.
Some examples are: Ruby-Throated Hummingbird - The nests are built, and the eggs incubated by the females. They lay immaculate white eggs and their clutch size is generally 2 tiny eggs. The eggs sit so deep in the cup-shaped nest that predators do not see them unless they stand directly over their nest. American Robin - This bird lays a bright blue-green egg in a mud-lined nest. They may even build their nest on the ground. Many eggs do not hatch because of the predators that easily rob the robin clutch. Blue Jay - These birds swiftly remove sharp eggshell fragments to protect their newly hatched brood from harm. Discarding shells also helps prevent both microbial infestations and pungent-smelling cues, that might alert nest predators about the location of the clutch. Only the female incubates the eggs, but both parents will provide food for the hungry chicks. Northern Cardinal - The beige base color and brown spots of the cardinal’s egg sharply contrast with the bright red plumage of the male parent. The female’s plumage is more of a subdued reddish-brown color allowing her to blend in with the nest and eggs. She is the sole incubator of the eggs. She also builds the delicate nest constructing the base by crushing twigs with her powerful beak. While building the nest, she is followed and fed by the male as part of his nuptial feedings.
Amazing Egg Facts: Despite the broad variety in colors and markings displayed by bird eggs, just two pigments are responsible for staining the shells. This includes all known species of living and extinct birds, including dinosaurs, a pear-shaped egg easily settles into the nest for protection. If parents decide not to build a next in will also settle on bare ground, eggshell colors are specific for the species of bird. For example, a brown-headed cowbird egg sticks out in the nest among an American robin’s blue egg. This allows the robin to recognize this egg as foreign and toss it out of her nest and the eggshell serves as a calcium supply for the growing embryo. As the embryo matures, the shell slowly becomes thinner and the hatchling has an easier time breaking through the shell.
Birds are truly fascinating creations of nature. They give us so much pleasure and beauty. If you have questions about the care of your pet, contact Dr. Norette L. Underwood of Trumann Animal Clinic at firstname.lastname@example.org