Predatory pumas taking their toll on Magellanic Penguins in Patagonia, say Oxford researchers

Vulnerable - Magellanic Penguins on a site in Patagonia (photo: Martin St-Amant via Wikimedia Commons)

A SURVEY has confirmed that Magellanic Penguins are falling prey to pumas in a wildlife refuge in southern Argentina.

According to a research paper in the Journal for Nature Conservation, more than 7,000 adult birds have become victims over a four-year period at Monte León National Park in Patagonia.

This figure represents about 7.6 per cent of the adult population of around 93,000 individuals.

It was about 130 years ago that the penguins began expanding their breeding range from islands off the coast to to the mainland.

This was a successful strategy while farmers were culling pumas and other potential predators to protect their cattle.

But in the wake of a decline in cattle ranching in southern Argentina in the early1990s, the pumas have returned and begun killing the defenceless penguins.

Marine birds are not normally the prey of  larger feline carnivores.  Many of the birds have only partially been eaten or not eaten at all, indicating that the killings were not solely for food. 

Says lead author Melisa Lera, a postgraduate student at Oxford University's Wildlife Conservation Research: "This is consistent with what ecologists describe as 'surplus killing'. 

"It is comparable to what is seen in domestic cats when prey is  abundant and/or vulnerable - ease of capture can lead to cats hunting more birds even when they do not end up actually eating them."

Study co-author Dr. Jorgelina Marino comments: "This study captures an emerging conservation challenge where recovering carnivores are encountering novel prey.

"Understanding how these dietary shifts affect both predators and prey is essential to inform conservation."

While the losses are dramatic, models show that pumas alone are unlikely to wipe out the colony.

 Greater dangers come from poor breeding and low survival among young penguins.

At Monte Leon National Park, researchers continue to  track both puma and penguin populations as they navigate the complex consequences of ecosystem recovery.

The report recommends that ongoing monitoring is essential to detect early signs of population decline and to guide management decisions before serious ecological damage occurs. 

* Another study, this time in the journal, Communications, Earth & Environment, suggests that droppings from penguins and other seabirds do their bit in addressing climate change by releasing ammonia which rises into the atmosphere and helps form clouds that deflect sunlight and protect sea ice. The research, by a team from the Unversity of Helsinki, was carried out in Antarctica close to a colony of 60,000 Adelie Peguins.