On Granite Island off South Australia, a colony of little penguins is fighting to survive. About two decades ago, the penguins numbered 1,600 adults – now there are just 30.
It is important for scientists to monitor and study this little penguin colony, to observe their behaviours and stop their numbers from declining.
In our latest research project, my colleagues and I captured footage of the penguins over several breeding seasons, as part of a study into their parenting behaviours. It provides a fascinating behind-the-scenes glimpse into the unseen world of these vulnerable birds.
So let’s take a look at what Granite Island’s little penguins get up to when humans aren’t watching.
The world’s tiniest penguin
Little penguins (Eudyptula novaehollandiae) are the world’s smallest penguin species. They typically grow to about 35 centimetres and weigh an average 1.2 kilograms. They live in coastal waters in Tasmania and southern Australia – including on Granite Island, about 100 kilometres south of Adelaide.
The island is connected to the mainland by a causeway, and draws up to 800,000 visitors a year.
The stark decline in little penguin numbers on Granite Island is due to several factors. They include predators such as fur seals and foxes, changing environmental conditions, declines in fish numbers, and human disturbance.
My colleagues and I have spent years studying the Granite Island penguin colony. Our latest research gathered thousands of hours of footage to determine if a particular personality trait – boldness – affected the penguins’ breeding and parenting.
Home after a day at sea
The footage starts with a stream of little penguins waddling under a boardwalk, returning from sea. They have spent most of the day in the water, hunting for food such as fish and squid. Little penguins forage about their body weight in food every day.
The penguins return to their nests after dark, to rest and feed their chicks. They do this in groups – possibly to avoid predators – before heading to their separate burrows.
They tend to travel quietly, to avoid attracting attention. But out at sea or back in their burrows, little penguins can be quite vocal, making sounds such as short quacks, growls and brays.
The footage shows one penguin bumping into another in the dark – but this doesn’t mean they don’t see well. Little penguins have excellent vision, even at night. Because the birds don’t move well on land, they often feel exposed and in a hurry to get home.
The birds are quite territorial and can get into disputes with others in the colony. The footage shows two males fighting by standing tall and pecking each other. One is probably defending its nest.
Hello, lover
Little penguins are monogamous. The breeding season runs over spring and summer, when there is lots of food around.
Males establish the burrows, which are usually in rock crevices or under thick vegetation. They then try to attract a female by demonstrating their quality – either through vocal displays or defending territory.
The footage shows a male and female penguin greeting each other, before getting down to business. Then we cut away, to give the lovebirds some privacy!
Across a breeding season, little penguin pairs typically rear one or two clutches during autumn and winter. Each clutch consists of one or two eggs. The penguins take turns sitting on the eggs while the other feeds at sea.
Keeping their plumage looking tip-top
In the footage we see two little penguins preening themselves during a quiet moment. This is important to remove parasites and keep their plumage healthy.
Despite their small bodies, little penguins have an estimated 10,000 feathers. The feathers are downy at the base, providing a layer of insulation which helps keep them warm during long days at sea.
The feathers are also waterproof thanks to an oily liquid the penguins secrete from a gland near their tails, which they spread over their body when preening.
Now for some family time
After the eggs hatch, the parents take turns to guard their chicks for three weeks while the partner fishes at sea. When this period ends, the parents leave the chicks alone in the burrow while they fish, returning every one to five days to feed them.
The footage shows the chicks excitedly jumping on a parent in the nest. We also see the chicks practising their vocal calls and stretching their tiny wings by flapping them madly. This is all important practice for being a grown-up penguin.
The parent-offspring relationship was the focus of our new research. When humans are around a lot – as they are at Granite Island – penguins can be bolder and more aggressive. We predicted bold individuals would invest less time in parental care, as has previously been observed in other bird species.
But this was not the case. We found a penguin’s boldness has no bearing on its performance as a parent, such as how often it returned to the nest, fed its chicks, or stayed overnight.
The next phase of our research will examine factors such as the quality of food the parents feed to chicks, or whether personality traits other than boldness might affect their child-rearing.
Protecting our little penguins
Humans are disturbing animal habitats at an alarming rate. We intend to keep studying – and filming – Granite Island’s little penguins to understand how this pressure is affecting them.
If you are ever lucky enough to observe little penguins anywhere in Australia, please take care of them by sticking to a few simple guidelines outlined in full here.
They include:
- stay at least five metres away
- don’t use camera flashes – it can temporarily blind the penguin
- don’t shine a torch directly at the penguin
- keep dogs away at all times
- don’t get between a penguin and its burrow or chicks.
Diane Colombelli-Négrel receives funding from the Waterhouse Club, Friends of Encounter Birds, the Save Granite Island Penguins Committee, the Sir Mark Mitchell Foundation and DEW Environment Citizen Science Small Grants.
This article was originally published on The Conversation. Read the original article.
