Changing with the times: little penguins exhibit flexibility in foraging behaviour and low behavioural consistency

Individual foraging consistency is commonly seen in wild populations, even in species considered generalists and allows individuals to forage more efficiently. It may, therefore, have important consequences on ecological processes, for individuals and populations. Within seabirds, data on timescales over which consistency is maintained is lacking, despite its potential to determine how adaptable individuals and populations are to face environmental changes. Little penguins (Eudyptula minor) were tracked at two colonies in south-eastern Australia during 5 years, using GPS data loggers and dive recorders. This study investigated the presence of behavioural consistency, its persistence through time and the influence of extrinsic and intrinsic factors on behaviour and consistency. Individual consistency was compared between colonies, among consecutive foraging trips, among different breeding stages/clutches and years. Individuals showed high plasticity, with foraging metrics influenced by site, year, stage/clutch. Low to moderate short-term consistency in foraging metrics was highlighted, except for bearing. Over larger timescales, no consistency in these metrics was detected. Mass and morphology are known to influence foraging behaviour and consistency, but seemed not to affect behavioural consistency, which varied with year and site instead. This further highlights the plasticity of animals foraging on prey highly spatially and temporally variable in their distribution. We emphasize the importance of taking timescale into account when assessing behavioural consistency. Finally, mechanisms other than behavioural consistency seem to allow little penguins to find mobile food in the water column (e.g. group foraging, and switching from short to long trips at specific times of the breeding season).

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