Atlantic puffin response to changes in capelin abundance in Newfoundland and Labrador : an inter-colony and inter-decade comparison

Abstract

I compared Atlantic Puffin chick diet and reproductive performance at the Gannet Islands, Labrador during 1996-98 to that recorded 1) in a similar study undertaken during 1981 -1983 at the Gannet Islands prior to a decline in capelin abundance, and 2) at Gull Island, Witless Bay, Newfoundland where capelin were abundant. I hypothesized that chick diet quality and breeding parameters would be dramatically lower at the Gannet Islands in the 1990s. During 1996-1998 at the Gannet Islands, puffin chick diet biomass comprised 3 to 25 % capelin and only in 1996 was breeding success dramatically lower (by 40 %) than any other study colony or year. Chick mass growth rate, and peak and fledging mass were lower in the 1990s than 1980s yet similar to that at Gull Island. Sandlance was the main alternate prey and was significantly higher in lipid, protein and energy density than capelin at both colonies. Atlantic Puffins exhibited behavioural plasticity with respect to foraging and reproduction in a temporally and spatially highly variable environment.