The world’s smallest penguins

By Elodie Camprasse

It’s 6.30 pm, just after sunset and I am sitting on a beach in southeast Australia, about to witness an amazing sight. Night after night during breeding season, around the same time, the world’s small penguins leave the water after a full day of fishing to cross the beach and reclaim the burrows they reproduce in. Group after group, they cautiously find their way back home to hungry chicks waiting for their parents to come home with bellyfuls of fish. We are in August and this is the start of chick rearing.

After having found and consolidated their burrows, the pairs, often faithful, have laid two eggs and incubated them for a bit more than a month. While chicks are young they cannot regulate their own temperature, so at least one parent needs to stay at the nest in order to keep them warm and protect them against predators. The other parent leaves at first light to go fishing with the mission to bring back enough food to sustain the offspring’s growth.

After about two weeks, when the chicks are old enough, both parents may leave the nest, for a day or even more, coming back less often to feed the patient little ones.  It will take the chicks about eight to ten weeks before they become independent and ready to cope with their new ocean life as they leave the comfort of the burrow. If environmental conditions are good enough, pairs will attempt to breed again and increase the number of offspring produced in one season.

Little penguins are also known as fairy penguins and are found both in the southern parts of Australia and in New Zealand where they represent major ecotourism attractions. They nest on offshore islands and on the mainland in places like the bottom of cliffs where predator access is restricted. Their burrows are dug in sand or soil but they can also nest under vegetation, in caves and in the crevices of rock falls.

As  their population has declined in some parts of their range, it has become more and more urgent to understand their ecology. They indeed suffer predation from rats, foxes and cats in addition to loss of habitat through human development and pollution via plastic and oil spills.

These birds have the smallest foraging range of all seabirds and are moreover, shallow pursuit divers because of their small size – about 40 centimeters. Recently, exciting research involving deploying dive behavior recorders and GPS trackers have shown that they are able to adapt to and benefit from anthropogenic alterations, show differences in parental effort and individual quality, as well as form at-sea associations in order to increase their hunting success.

They also seem to display individual specializations in diving behavior and dependability upon a given foraging area. Ongoing studies are in fact trying to understand whether or not being a generalist or a specialist is a better strategy for them to efficiently forage, and ultimately increase their reproductive success. Studying the penguins’ diet through blood samples is looking at evidence of prey preferences at different times during the breeding season that will also help researchers determine whether or not the birds exhibit consistent strategies. This is a fairly new area of interest in seabird research in general, which will assist in understanding how those animals can cope with climate change and habitat modifications.

Adapting to an artificially modified environment

There are some examples of wild animals adapting to urban life. I remember observing sea lions at pier 39 in San Francisco trying to understand why they would choose such a location and how they could cope with human disturbance. The same question popped into my head as I contemplated tourists photographing and observing little penguins on the Saint Kilda breakwater wall in Melbourne. Amazingly, hundreds of breeding pairs have been able to successfully establish themselves in between the rocks of the breakwater. They’re able to exploit food resources within the Port Phillip bay and are thought to use the three-dimensional structure of human-dug shipping channels to trap their prey.

A study has certainly reported differences between the little penguins’ diving habits in natural environments compared to the ones they exhibit in the bay which involve more time spent diving close to the sea floor. Part of the birds’ success also lies in the fact that there is a secure fence preventing predators from accessing the colony. They are however, exposed to other associated threats such as  a public desire to further modify their foraging environment by deepening the shipping channels, which will increase water turbidity and therefore influence both the penguins’ and their prey’s behaviour. Unfortunately, this could jeopardize the little penguins’ survival in this highly modified environment. Saint Kilda is not an exception though and little penguins use other urban locations and modified environments such as former quarries and harbors in Oam