Effects of double brooding on productivity of crested Caracaras

During at least one of three nesting seasons, 13 breeding pairs of Crested Caracaras (Caracara plancus) in south-central Florida made a second nesting attempt following a successful first attempt. Ten pairs successfully fledg ed young in both attempts. Only early nesting pairs attempted a second broo d. Most double-brooded pairs fledged their first brood before 1 March. The time interval between first and second nesting attempts was positively corr elated with the number of young fledged from the first attempt. Clutch size declined between first and second nests of double-brooded pairs, and secon d nests failed more often, but pairs that attempted two broods in a season fledged significantly more young than did single-brooded pairs. Estimates o f survivorship to recruitment were higher for young from first broods than for young from single or second broods. Although the influence of double br ooding on annual productivity seems only marginal, this strategy likely per sists because of the potential increase in fitness incurred by individuals that successfully fledge two sets of young in a single nesting season.