Balearic Shearwater - Puffinus mauretanicus
Status: Critically Endangered … Whilst their one egg is incubating, parents take it in turns to feed at sea
Location: Breeding adults return to the Balearic Islands where they nest between February and June. In winter the birds live out to sea, mainly staying around the Balearic Sea and off the north-east coast of Spain and Portugal. However, many Balearic Shearwaters migrate north in summer to feed in seas off the British Isles and the south of the Scandinavian Peninsula.
Size: Approx 40 cm long, 90 cm wingspan
Habitat: Open ocean, but breeds on rocky cliffs and islets.
With an annual decline of around 8%, the Balearic Shearwater is one of the rarest seabirds in the world. Whilst the Balearic region gives this bird its name, some travel as far north as the Orkneys and Shetland Islands and the southern Scandinavian Peninsula.
Threats to this magnificent bird are wide-ranging. Urbanisation has destroyed some nesting sites. As well as being preyed upon by cats, rats and genets at the breeding sites, many Balearic Shearwaters are killed when caught in fishing gear at sea. Marine pollution, such as oil spills, can also cause significant mortalities at sea. If declines continue at the current rate, the Balearic Shearwater could become extinct within 40 years.
It’s difficult to estimate the true population accurately; the species tends to have a large floating population of non-breeders and immature birds. However, recent estimates suggest there are 20,000 to 30,000 individual birds left worldwide. The IUCN also reports a general shift north in the distribution of the Balearic Shearwater’s non-breeding population. This may have arisen as a result of climate change or changes in the distribution of their prey species such as sardines, squid and herring.
During the breeding season, Balearic Shearwaters favour the warmer regions of the east coast of Spain and the Balearic Islands which give them their name.
During poor breeding seasons, pairs may ‘divorce’!
Did you know?
- They nest in colonies of several hundred, and the female lays just one large egg.
- Whilst the egg is being incubated, the parents take turns feeding at sea. Chicks grow quickly and will breed from around three years of age.
- It has two tubular nostrils on its upper bill, a unique feature of the shearwaters, albatrosses and petrels.
- Its long, thin beak has a slight hook and sharp blades that enable the Balearic shearwater to catch slippery fish after plunge-diving into the water or following an underwater pursuit.
What MCS is doing:
- Working towards better protection of Balearic Shearwater marine habitats in the UK;
- Working towards better management of fisheries that can impact shearwaters and their prey;
- Combating marine litter that threatens seabirds like the shearwater.