Intraspecific nest parasitism and adoption of young in the barnacle goose : effects on survival and reproductive performance

• DNA fingerprinting was used to determine the proportion of extra-pair young in a population of barnacle geese, Branta leticopsis, breeding in the Baltic area, Sweden. Of 137 analysed fledged young 17% were found to be extra-pair young. One or more extra-pair young were found in 27% of the 63 analysed families. The proportion of extra-pair young differed between years. No case of extra-pair fertilization was detected. All extra-pair young at fledgling originated either from intraspecific nest parasitism or from adoptions of foreign hatched young. Broods with extra-pair young at fledgling were significantly larger than broods without extra-pair young. However, the number of within-pair young did not differ significantly in broods with and without extra-pair young. Body mass, survival or subsequent reproductive performance did not differ between parents with and without extra-pair fledged young. Post-fledgling survival and age at first breeding were not significantly different between the three analysed classes of fledged young, i.e., within-pair young in families without extra-pair young, within-pair young in families with at least one extra-pair young, and extra-pair young. It is concluded that possible costs or benefits associated with caring for extra-pair fledged young are small or absent in this population.

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NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

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Natural Science

Naturvetenskap

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