How Do Birds Lay Eggs?
- The nest of a Shorebird
Before a female bird can start laying eggs, she needs to construct a nest. Nests can be made from a variety of natural or man-made materials, such as twigs, grass, leaves, mud, string, plastic or paper. Location of the nest is also an important factor the bird must consider since she is about to lay eggs packed full of nutrition and protein, which will be highly sought after by predators. - Reproductive system of a female bird
During the breeding season, a bird's ovary will become enlarged and release an egg that is then passed into the oviduct where fertilization will take place. As the newly fertilized egg passes through the oviduct, egg white (albumin), shell membranes and shell are added to it just before the moist egg pops out.
Birds generally lay between 1-20 eggs, usually only producing one egg a day. Egg size can vary depending on the size of the bird--from 13 inches for the extinct elephant bird to 1/3 of an inch for the hummingbird. - Incubation has started for this Grey Fantail
Incubation begins after the last egg is laid and varies in length from 10 to 80 days. Normally, eggs with short incubation periods will produce chicks with thin skin that require a lot of protection and food from their parents. Eggs with longer incubation periods will hatch chicks with thick plumage that will not require a long stay in the nest. Depending on the breed, incubation can be shared between the male and female, or can be solely performed by one gender only.
Building the Nest
Fertilization
Incubation
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