Inflexible parenting risky for penguin mums and dads

A female Eastern Rockhopper Penguin feeds its 12-day-old chick. Photo credit: Kyle Morrison.

Rigid adherence to parenting styles in crested penguins may leave them vulnerable to food shortages brought about by climate change, according to a paper published in Behavioral Ecology and Sociobiology.

Eudyptes (crested) penguins adopt a unique division of labour, where males starve themselves to guard their chicks in the first three weeks of their chicks’ lives, while females find food for the chick. Males join females in feeding chicks later in the “crèche stage” but only after males spend several days at sea feeding to regain the body mass they have lost. This strategy of Eudyptes penguins differs from that of all other penguin species, who alternate feeding and guarding duties every one to 12 days.

Researchers from Massey University and the National Institute of Water and Atmospheric Research in New Zealand alongside scientists from Canada, the United States and England, studied Eastern Rockhopper Penguins (Eudyptes chrysocome filholi) on New Zealand’s sub-Antarctic Campbell Island over two consecutive breeding seasons – one where food was abundant (2011) and one lean year (2012).

The researchers recorded how often chicks were fed, their size at one month old, how long adult birds spent away from the island and the colony’s overall success in raising chicks.

The team found parents were not adapting their rigid division of labour in times when food sources were scarce, meaning chicks reared in 2012 were fed less and grew more slowly. Adult males also spent more time at sea in search of food to regain their body mass, leaving chicks underfed.

Lead author on the paper Kyle Morrison, from Massey’s Institute of Agriculture and Environment, says this stubbornness is not suited to ensure chicks grow and survive as well as possible, especially as food supplies are more frequently low as a result of climate change.

The scientists estimate that if Eudyptes penguins were to share guarding and foraging duties equally, up to 34.5 per cent more feeds could be provided to their chicks.

They note however, that it is not easy for the penguins to change their breeding strategy because the smaller, less aggressive females would be less effective in the role of guarding chicks.

The full paper is available here.

Eastern Rockhopper penguins on Campbell Island. Photo credit: Kyle Morrison.

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