Prey size selectivity by Kelp Gulls on Antarctic Limpets at King George Island, Antarctica

SILVA MP, M FAVERO & MM MARTÍNEZ

POLAR BIOLOGY

Año: 1999 vol. 21 p. 397 - 400

0722-4060

The present study was performed at Potter Peninsula (King George Island, Antarctica) with the following goals: (1) to assess the size selection of kelp gulls on Antarctic limpets during the chick-rearing period, and  2) to evaluate the degree of accuracy in the use of populational abundance and size-frequency distribution  as an indicator of prey availability. The average size of limpets available to kelp gulls was signicantly smaller than that of the population as a whole and those actually consumed by gulls. The odds ratio revealed a strong selectivity for large limpets, when available and consumed sizes were compared. However, only a proportion of the limpets present was available to gulls. These di€erences clearly show that using abundance information as an indicator of a resource importance can lead to substantial errors in ecological interpretations.