Growth of Dovekie ( Alle alle ) chicks under conditions of increased food demand at the nest: two field experiments

• Published in: Canadian Journal of Zoology
• Main Authors: Gębczyński, Andrzej, Taylor, Jan R. E., Konarzewski, Marek
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1996
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Arctic; Alle alle; Dovekie
• Online Access: http://dx.doi.org/10.1139/z96-119; http://www.nrcresearchpress.com/doi/pdf/10.1139/z96-119

To test whether Dovekies, Alle alle (small arctic alcids laying single-egg clutches), can increase parental effort, we increased food demand in their nests in two experiments. First, we introduced a second chick to the nests. Second, we rotated a number of chicks among a smaller number of nests, producing equivalents of 2, 1.5, and 1 (control) chicks per nest. Fledging success in the nests with twins (0.63 chick per nest) was higher than in unmanipulated broods of 1 chick (0.46 chick per nest). Chicks that fledged successfully in the two experiments grew at significantly lower rates and fledged at lower body masses and later than did rotated control chicks and unmanipulated single chicks. The latter two groups did not differ one from another. Growth rates and body masses of the chicks from the 2/1 rotation group (equivalent to 2 chicks per nest) were too low to indicate any substantial increase in the rate of provisioning by adults (over the rate satisfying the maximum energy consumption of an unmanipulated single chick). We associate this with the adults' energetically expensive mode of foraging and high field metabolic rates. However, the deferred fledging of rotated and twinned chicks might have considerably increased the total food demand in their nests (from hatching to fledging) that had to be met by the parents.