Laying an Egg

Hormones signal egg laying

Hormones are biochemicals produced by endocrine glands in the body. They control the timing of egg production and laying. Environmental conditions such as day length, temperature, food availability and precipitation, influence the endocrine glands to secrete appropriate hormones. Eggs are thus laid at a time of year when they are likely to hatch and nestlings are likely to survive.

Eggs are laid every day

Birds usually lay eggs at one-day intervals until they have completed their clutch. Larger birds typically require longer times between layings than do smaller birds. Some kiwis, eagles and vultures take four or five days between eggs.

Eggs for breakfast

Most often, birds lay their eggs early in the morning. Birds move around less at night, so shell formation occurs more readily.

Parasites are fast layers

Some birds take only a few seconds to lay an egg. Brood parasites, which lay their eggs in another bird's nest, are particularly fast layers. The female Cowbird watches and waits until her target nest is unattended, darts in, lays the egg and leaves. Other birds such as the Canada Goose, require about an hour to lay an egg.

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