The foraging and reproductive ecology of a resident, inshore seabird, the little penguin

Nicole Daniela Kowalczyk
Coastal and inshore, resident seabirds forage in close proximity to their breeding colonies year-round. Compared to offshore and pelagic seabirds that can travel widely in search of adequate resources, inshore residents rely on locally abundant prey stocks, making them particularly vulnerable to shifts in prey availability and distribution. Relatively few studies have assessed how these seabirds are equipped to deal with environmental variability and fluctuations in their local resources. These
more » ... knowledge gaps hamper the effective management and conservation of their habitat resources and prey, and limit our ability to predict how seabirds will respond to shifts in prey availability. Using the St Kilda little penguin (Eudyptula minor) colony as a model species, this thesis addressed knowledge gaps in the foraging and reproductive ecology of inshore, resident seabirds. Stable isotope analyses in combination with previously published records of stomach content data were used to reconstruct the diet of little penguins during the breeding and non-breeding season over four years. This examination confirmed that little penguins are generalist predators that forage opportunistically within Port Phillip Bay, on a predominantly anchovy (Engraulis australis) based diet. The study found that during the breeding season, penguins exploit prey species that enter the bay from offshore waters to spawn and during the non-breeding season, penguins exploit juvenile fish communities, which use the bay as a nursery and dominate the prey biomass in the winter months. Due to this continuous supply of prey, combined with the opportunistic foraging strategies of little penguins, St Kilda penguins can remain in the bay year-round. GPS analysis combined with environmental data was then used to determine penguin foraging habitat preferences in the bay. This investigation found penguins predominantly occurred in productive waters, with low turbidity. These findings indicate inshore residents maximise net energy gain by foraging opportunistica [...]
doi:10.4225/03/58b63526059ed fatcat:gaxc772uefa6xnicx4eya7owvu