Influence of Chick Mass and Date at Departure from the Colony on Adult Characteristics in Ancient Murrelets (Synthliboramphus Antiquus), A Precocial Seabird

Abstract

Abstract I investigated the effect of mass and date of departure of Ancient Murrelet (Synthliboramphus antiquus) chicks reared at two colonies in Haida Gwaii, British Columbia, on aspects of their adult biology. Chicks were captured, banded, and weighed while departing from their natal colony at two to three days old, during 1984–1998. Adults were recaptured at the same colonies during the breeding seasons of 1986–2000. Just under 1% of 13,055 chicks were recaptured as adults. Chicks that were heavier than average at colony departure were recaptured as adults at a younger age and were heavier as breeders than lighter chicks. However, chick departure mass did not affect adult mass of birds recaptured as nonbreeders. The date at which chicks left the colony had no effect on either adult mass or age at recapture. Correlation between chick mass at colony departure and adult mass as a breeder is rarely reported and is difficult to explain. However, if chick mass is determined by reproductive investment on the part of the parents and adult mass is a measure of reproductive investment by the individual, the correlation suggests that degree of parental investment could be a heritable trait.