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Is sex-specific mass gain in Cory's shearwaters Calonectris diomedea related to begging and steroid hormone expression?

journal contribution
posted on 01.03.2007, 00:00 authored by P Quillfeldt, I Träger, K Griffith, Kate BuchananKate Buchanan, J Masello
Mass differences between the sexes of dimorphic bird species often appear early in the nestling development. But how do adults know how much to feed a chick in a sexually dimorphic species? Do chicks of the heavier sex beg more? We studied begging in Cory’s shearwaters Calonectris diomedea, a species with heavier adult and juvenile males than females. We found that begging rates and call numbers were not different between male and female chicks, but parameters of begging intensity differed between the sexes in their relationship to chick body condition. For the same body condition, males had significantly higher begging call numbers and rates. Acoustical parameters, which were analysed semi-automatically, included the lengths of call and silence intervals, the minimum, mean and maximum frequency in a call and the number of frequency peaks within a call. We found no consistent differences of acoustic begging call elements between the sexes. Male and female chicks did not differ in the levels of the steroid hormones testosterone or corticosterone in the second quarter of the nestling period, and the mechanism leading to sex-related differences in begging rates for a given body condition remains unknown.

History

Journal

Behavioral ecology and sociobiology

Volume

61

Issue

5

Pagination

793 - 800

Publisher

Springer Berlin / Heidelberg

Location

Berlin, Germany

ISSN

0340-5443

eISSN

1432-0762

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2006, Springer-Verlag