In keeping with the events of the past several days, i.e., the arrival of the Boise eyases (peregrine chicks), the Peregrine Fund has this article on their web page today. Interesting information.
Immediately prior to hatching, the yolk inside the egg, which nourished the embryo during incubation, was absorbed into the young birds’ body cavity. The yolk continues to sustain a chick for several days, even without supplemental feeding by the parents. However, the chicks’ begging instinct kicks in right away and the adults are feeding the chicks small amounts of food every day. The adults know just how much each chick needs to eat daily.
Back in the 1970s, The Peregrine Fund became highly effective at raising chicks in captivity, but knowing when and how much to feed chicks proved tricky at first because of the chicks’ constant begging. Biologists soon learned exactly how much the chicks needed and, thus, avoided overfeeding them in response to cries that sound to human ears like, “more, more, more.” The Peregrine Fund successfully raised and released more than 4,000 Peregrine Falcon chicks to the wild, but we know we can never do it as well as the chicks’ natural parents.