Sexual segregation in distribution, diet and trophic level of seabirds: insights from stable isotope analysis

Contrasting specialist and generalist patterns facilitate foraging niche partitioning in sympatric populations of Pygoscelis penguins

“…The only evidence of sexual differences ob served in our study was the higher number of otoliths in female penguins' stomach samples, though this was not consistent in all years. This suggests that factors such as differences in foraging habitat across sites and interannual or spatial variation in resource availability may mediate the degree and consistency of sexual variation in gentoo penguin diets, similar to results found in other seabirds (Miller et al 2010, Phillips et al 2011.…”

“…While often difficult to distinguish, generalist populations may be composed of generalist individuals all taking a wide range of food types (Type A generalists) or individuals each specializing in a different range of food types that combine to form a large population niche width (Type B generalists; Grant et al 1976, Bearhop et al 2004. Differences between sexes within generalist populations can also lead to large total population niches while limiting intraspecific competition (Phillips et al 2011).…”

Drivers of intrapopulation variation in resource use in a generalist predator, the macaroni penguin

“…Likewise, the skewed distribution of males towards lower δ 13 C class may reflect the slight sexual dimorphism that is present in macaroni penguins. This mechanism has been found in a variety of sexually dimorphic seabirds (Phillips et al 2011).…”

Consistency pays: sex differences and fitness consequences of behavioural specialization in a wide-ranging seabird

“…Here, individual divergence in niche is widely reported, particularly between the sexes [4,10,11] where it is often thought to arise as a result of sexual size dimorphism [11], differences in nutritional demands (e.g. [10]) or competitive ability (e.g.…”