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Flexibility in the parental effort of an Arctic-breeding seabird

Functional Ecology

By:
, , , , , , ,
DOI: 10.1111/j.1365-2435.2008.01488.x

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Abstract

Parental investment strategies are considered to represent a trade-off between the benefits of investment in current offspring and costs to future reproduction. Due to their high residual reproductive value, long-lived organisms are predicted to be more reluctant to increase parental effort. 2. We tested the hypothesis that breeding little auks (Alle alle) have a fixed level of reproductive investment, and thus reduce parental effort when costs associated with reproduction increase. 3. To test this hypothesis we experimentally increased the flight costs of breeding little auks via feather clipping. In 2005 we examined changes in the condition of manipulated parents, of the mates of manipulated parents, and of their chick as direct measures of change in parental resource allocation between self-maintenance and current reproduction. In 2007 we increased sample sizes to determine whether there was a physiological cost (elevated corticosterone, CORT) associated with the manipulation. 4. We found that: (i) clipped birds and their mates lost more body mass than controls, but there was no difference in mass loss between members of a pair; (ii) clipped birds had higher CORT levels than control birds; (iii) there were no inter-annual differences in body mass and CORT levels between clipped individuals and their mates at recapture, and (iv) chicks with a clipped parent had lower peak and fledging mass, and higher CORT levels than control chicks in both years. 5. Contrary to our hypothesis, the reduction in body mass of partners to clipped birds suggests that little auks can increase parental effort to some extent. Nonetheless, the lower fledging mass and higher CORT of chicks with a clipped parent indicates provisioning rates may not have been fully maintained. 6. As predicted by life-history theory, there may be a threshold to the additional reproductive costs breeders will accept, with parents prioritizing self-maintenance over increased provisioning effort when foraging costs become too high. ?? 2008 British Ecological Society.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Flexibility in the parental effort of an Arctic-breeding seabird
Series title:
Functional Ecology
DOI:
10.1111/j.1365-2435.2008.01488.x
Volume
23
Issue:
2
Year Published:
2009
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Functional Ecology
First page:
348
Last page:
358
Number of Pages:
11