Response of Adult Leach's Storm-Petrels to Increased Food Demand at the Nest

• Published in: The Auk
• Main Author: Ricklefs, Robert E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 1987
• Subjects: Kent Island; Oceanodroma leucorhoa
• Online Access: http://dx.doi.org/10.1093/auk/104.4.750; http://academic.oup.com/auk/article-pdf/104/4/750/30081656/auk0750.pdf

Abstract In a colony of Leach's Storm-Petrels (Oceanodroma leucorhoa) on Kent Island, New Brunswick, i chicks were rotated on a daily basis through n nests to produce i/n chick-equivalents of food requirement, increasing by small increments from 1 (i = 6, n = 6) to 2 (i = 2, n = 1), between ages 10 and 50 days. Food delivered each night (SUM) was estimated by 24-h increments in chick mass. In nonexperimental nests SUM varied significantly among pairs, and chick mass varied in direct relation to SUM. Adults tending experimental nests did not respond to increased food demand, and chick mass decreased with increasing chick-equivalent per nest. After rotations were terminated, the mass of most chicks increased quickly to normal levels. These results suggest that the average amount of food delivered daily by each parent is determined independently of food demand and that chicks attain a mass that balances a fixed food intake against food requirement, which varies in direct relation to mass.