| Publication Type: | Journal Article |
| Year of Publication: | 1997 |
| Authors: | Catry, P, Furness, RW |
| Journal: | Colonial Waterbirds |
| Volume: | 20 |
| Issue: | 3 |
| Date Published: | 1997 |
| ISBN Number: | 07386028 |
| Keywords: | Catharacta, Catharacta skua, Stercorariidae, Stercorarius, Stercorarius skua |
| Abstract: | In gulls, egg size and clutch asymmetry have been suggested to be suitable variables for assessing individual quality. Skuas, like several other seabirds, generally display within-clutch asymmetry (the second egg in the clutch is, on average, smaller than the first egg). We found no relationship between clutch volume in 2-egg clutches and laying date, hatching success or fledging production of pairs of Great Skuas (Catharacta skua) breeding in Shetland. There was a high repeatability (0.72, P < 0.0001) in the volume of clutches laid by the same pairs in consecutive years. The influence of adult age on egg size was weak and variable. Unlike clutch volume, clutch asymmetry was not repeatable and showed no relationship with adult age. Furthermore, clutch asymmetry did not correlate with any other breeding parameter. We conclude that, in Great Skuas, clutch characteristics are not suitable indicators of individual quality or environmental conditions over the range prevailing during this study. The results are discussed in comparison with the conclusions from studies with gulls, and it is argued that more research is needed to clarify the factors that are responsible for the existence of within-clutch asymmetry in seabirds. |
| URL: | http://www.jstor.org/stable/1521589 |
| Short Title: | Colonial Waterbirds |
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