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Whooper Recount: A Close Look At These Endangered Cranes Reveals That, While Their Numbers Are Increasing, Their Rate Of Increase Is Actually Declining, Paul A. Johnsgard

Papers in Ornithology

I have assembled figures for the 43-year period from 1938 through 1980, and have subjected them to various kinds of analysis. During this period, 220 young and 1,437 postjuvenile birds have appeared on the wintering grounds. This works out to an annual recruitment rate of 13.3 percent. (This is not exactly the same as the birthrate, of course, since the loss of eggs, chicks, and juveniles prior to arrival at Aransas is excluded.) The recruitment rate provides an estimate of the rate of maximum annual population increase. One hundred fifty-four birds that had been counted in any given year failed …