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The mystery of the disappearing black guillemot

The black guillemot (Teista in Icelandic, Cepphus grylle in Latin) has long been one of the most numerous birds around Iceland.

The black guillemot (Teista in Icelandic, Cepphus grylle in Latin) has long been one of the most numerous birds around Iceland.

This is a long-living seabird of the Alcidae family, and it’s really quite pretty.

It is completely black with white dots on its wings, and has red feet. When it opens its mouth, one can see the same rich red, but the long, sharp beak is black.

In winter, they change colour and become surprisingly light compared to other Alcidae, almost grey.

During this time, the white dot becomes less pronounced.

A fully grown adult is about 32 centimetres long, and weighs between 300 and 550 grams. Its wingspan can be over half a metre long.

According to the Natural History Museum of Kopavogur, about 30,000 to 50,000 pairs nest in Iceland each summer.

This bird generally holds tightly onto traditions.

Largely monogamous, couples rarely separate until death.

In Iceland, the birds gather in colonies of about 80 couples or fewer, and each couple usually nests in the same hole year after year.

They pick their holes fairly far from each other, and never in groups as large as those of other Alcidae birds.

For their sites, they pick rocky hills near the ocean, rock walls or even hide under driftwood on the rocky shore.

The black guillemot has two eggs, whereas other Alcidae birds only have one, and the eggs are white and brownish, or light-green with black, reddish-brown and grey drizzles.

Their nesting time is long.

The first young hatch in the middle of May, and some don’t leave the hole until the beginning of September.

They stay in the nest for about 40 days, while both parents work hard at feeding them.

The young cannot fly until they leave the nest, after which they become fully fledged in less than a week, and as soon as they reach the ocean, they have no need for their parents anymore.

Few have been know to move far from their original nesting hole, and young birds, who begin to nest at age two to four years, usually pick a site near to where they were born.

But aside from nesting, the black guillemot does not come to shore, and when this period is over, usually in late July or early August, the bird disappears from the nesting grounds.

However, it rarely goes far.

Unlike other Alcidae birds, the black guillemot does not go far onto the big sea and the adults don’t stray far from their nesting grounds in winter — when about 50,000 to 100,000 birds are thought to be scattered around the country.

The young, however, go slightly further out to sea.

Like college students, they travel during the years before they begin nesting, and have been known to go as far as Greenland.

In March, the adults return to their nesting grounds, though nesting does not begin again until late in May or even June.

Black guillemots live in shallow ocean waters all year. They dive for bottom-feeding prey.

The bird can fly very fast, is a great diver and can stay underwater for over a minute.

Humans have long eaten the black guillemot, and a hunter can catch both young and adults from September 1 to May 10.

However, very few people today enjoy black guillemots or other Alcidae birds, due to the strong fishy taste.

The few who hunt them do so from boats in winter.

The bird was sometimes named after Saint Peter, or Péturskofa, and it was considered bad luck to hunt an adult bird over the nesting period.

The black guillemot hasn’t been studied much in Iceland, a fact that may be about to change.

Well-known and much respected bird-watching couple, Björk Gudjónsdóttir and Jón Hallur Jóhannsson, have long studied the Black Guillemot nesting sites in Strandir, and they’ve brought some very interesting news to scientists. These were reported on in a recent issue of the bird enthusiast magazine of Iceland.

According to Björk and Jón Hallur, several black guillemot nesting sites, that thrived around the 1950s, have now been deserted.

The situation is particularly bad in the Strandir-area, in Iceland’s northwest.

On Strandir only one new spot has been colonized by the bird in the past few decades.

Scientists have no idea why the black guillemot are disappearing, and do not know if the bird is generally diminishing in numbers, or if it is simply finding other nesting sites.

But more and more people are beginning to pay attention to this issue.

Many scientists and birdwatchers suspect that the introduction of mink in Iceland in the mid 1900s is much to blame for the diminishing number of black guillemot nesting sites.

But another reason could be increased fishing of female lumpfish, a favourite food of the bird.

Another threat is the proliferation of puffins, a serious rival.

Another threat could be changes brought on by global warming.

The reason hasn’t been pinned down, but it will be interesting to follow the coming research.