Source: Bird Eggs 2

Length of Segment: 00:01:17

Hi, I'm Dr. Jerry Jackson, out with the wild things. The number of eggs that a bird lays during one nesting effort is called a ‘clutch’. A female is capable of laying only one egg per day, and in some birds that lay large eggs, such as our vultures, there may be two or more days between eggs. Some birds nearly always lay the same number of eggs. Doves, for example, usually lay a clutch of only two eggs, and killdeer almost always lay four eggs. In other birds, the normal clutch size can vary with age of the female, time of the nesting season, and geographic location. Young birds nesting for the first time often lay fewer eggs than older birds. Birds nesting early in the season often lay more eggs than those nesting later. Those birds living close to the equator have smaller average clutches than those distant from the equator. At the equator, there is always twelve hours of daylight and twelve hours of darkness, and birds can only raise as many young as they can provide food for during the short day. Away from the equator, and with more daylight hours, birds can raise more young. By the way, the ancestors of our domestic chickens normally had a clutch size of twelve eggs, which is why we normally buy eggs by the dozen.

'With the Wild Things' is produced at the Whitaker Center in the College of Arts and Sciences at Florida Gulf Coast University. For 'The Wild Things', I'm Dr, Jerry Jackson.



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