When we think of seabirds, it’s usually the biggest that spring to mind—usually albatrosses and the like. Accordingly, they seem to dominate the news when it comes to conservation concerns. However, not all seabirds are big; indeed, some are quite the opposite. The storm-petrels are the smallest of the world’s seabirds, and they usually fly under the radar. The White-faced Storm-Petrel is the only storm-petrel that breeds on nearshore islands around the Australian coastline, and the only of them to breed anywhere near one of our capital cities.
One such colony exists on Mud Island, at the southern end of Port Phillip Bay. However, not all is well. In the 1950s, the breeding population of these birds on Mud Island was estimated at up to 10,000 pairs, but since then the numbers have dropped off steadily. By the 1984, the numbers had declined by around 90 per cent, with around 1000 pairs present. Apart from occasional flurries of interest, little work has been done on the Mud Island colony since.
In February, a team from BirdLife Australia visited Mud Island to monitor a small Fairy Tern colony, but they also visited the White-faced Storm-Petrel, on the other side of the island.
What they saw shocked them. Although it was far from a comprehensive survey, only a handful of nesting burrows could be found, and although the timing of the visit was several weeks before the chicks were due to fledge, only one chick could be found in its burrow.
The site of the colony is known as ‘the runway’, which suggests that in the past it was an open area with low and sparse vegetation. That is not the situation any more. The runway is now the site of a substantial colony of Australian White Ibis and Silver Gulls, whose nests cover much of the landscape. Feeding at nearby rubbish tips, the gulls and ibis have taken full advantage of city living, and are flourishing.
With the establishment of the ibis and gull colonies, the vegetation of the runway has changed. Now, fertilised by so many birds’ copious droppings, the soil is more fertile than ever before and this has allowed shrubby weeds to become established. The site is now overgrown with them, making the area less than ideal for nesting seabirds, severely restricting their access to burrows and preventing them from taking off. It’s no wonder the colony has shrunk.
The IUCN lists the White-faced Storm-Petrel’s conservation status as Least Concern, and it’s estimated that the world population comprises 4 million birds, so the decline of a small colony in Port Phillip Bay will have little impact on the overall scheme of things.
Nevertheless, a breeding colony of these diminutive birds almost within sight of one of Australia’s biggest cities should be regarded as a natural treasure. Instead, it seems to have been all but forgotten.