Spot the Black Guillemot in Iceland

The Black guillemot (Cepphus grylle) belongs to the Alcid family (Alcidae) along with the puffin (Fratercula arctica), the common murre (Uria aalge), the thick-billed murre (Uria lomvia), the razorbill (Alca torda) and the rare little auk (Alle alle). The Black guillemot is an arctic bird species that occupies many areas of the coastline in the North Atlantic and North America. Five subspecies of the Black guillemot are found in the world, but the Icelandic subspecies Cepphus grylle islandicus is only found around Iceland.

A Dark and Beautiful Redstocking

The Black guillemot is a very dark alcid with black body feathers but a white spot on the wing and white underwing feathers that are seen during flight. The Black guillemot has a black belly, but other alcids have a white belly. The bill is black and pointy, but the mouth, tongue and feet are bright red, while the bird has its summer plumage. Juveniles and adults in winter plumage look alike.

They have a greyish belly but a darker upper body with yellowish feet. The Black guillemot weighs 397 to 500 grams (14-17.6 oz) and is 30 to 26 centimetres (12-18 in) in length. It is a good diver like other alcids, flies fast but low over the sea and walks quite a bit around her nesting area.

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Distribution and Population Size

The Black Guillemot nests all around Iceland but is very sparse on the south coast due to a lack of good nesting sites. The main habitat is found at the shallow Breiðafjörður, with abundant nesting sites on its rocky shores. Unlike other alcids, the Black guillemot does not nest in dense colonies but is sparsely distributed along the coast between large rocks. The Black Guillemot is mostly stationary in Iceland. It stays close to the shore all year around, but there have been a few marked Icelandic birds spotted close to Greenland; it is mostly juveniles that roam that far. 

The Icelandic population has decreased over the past years, and birds have moved from the mainland coast to islands and islets. The mink (Mustela vison) is one of the reasons that the Black Guillemot has moved from many old nesting areas, as the birds in their nests are easy prey for the mink. Many Black guillemots also drown in lumpsucker fishing nets in the spring, which are laid in shallow waters where the birds also feed. 

The collapse of the sand eel population in 2005 also had a big negative impact on the Black guillemot population. Black Guillemots were not hunted widely in Iceland over the years, and in 2017, a hunting ban was established. The population size is not fully known but is probably 10000-15000 breeding pairs.

The Courtship of the Black Guillemot is a Beautiful Sight

In late February, the Black guillemot start to gather on sheltered shores to start their mating rituals. They pair for life, and like other alcids, the pair bonds are strong. The courtship of Black guillemot pairs is an interesting phenomenon. It resembles the waterdance of grebes (Podicipedidae) and loons (Gaviidae). 

They bow and brake on the ocean, dive, and run on the watercolour. This strange behaviour is a magnificent sight. This mating ritual is followed with a high-pitched whistle sound, which is the origin of the Icelandic name "teista". The whistle sound is a beautiful bird language that is fun to hear in the spring, but the Black guillemot is otherwise silent.

Nesting and Feeding Habits of the Black Guillemot

Each pair has its own nesting site; the nest is most often in crevices on rocky shores or between large rocks in man-made rock fences. The Black Guillemot is the only alcid that lays two eggs in the nest. The eggs are white or creamy coloured with dark spots and weigh about 1.8 oz each. The incubation is about 30 days. 

Both parents care for the young, which stays in the nest until it goes out to sea 30-40 days old. The Black guillemot feeds mostly on sand eel (Ammodytes marinus) and rock gunnel (Pholis gunnellus), which is sometimes called butterfish or "teistu-fish "after the Icelandic name of the Black guillemot. It also feeds on other small fishes, crustaceans and invertebrates from the ocean.

Why Is It Called Teista?

The Black guillemot is called "teista "in Icelandic but also "þeisti "or "teisti ". All these names have their origin in the whistle sound of the bird. The chicks of the Black guillemot were harvested for meat and feathers back in the old days, a tradition that is not practised today.

Five Facts About the Black Guillemot  

1. There are five subspecies of Black guillemots in the world, and the Icelandic one is a special sub-specie, Cepphus grylle islandicus.
2. The Black Guillemot is the only alcid that lays two eggs. They become mature at four years old and are loyal to both their companion and nesting site.
3. The oldest Black guillemot was marked and recovered in Alaska at 27 years old.
4. The main food items are rock gunnels and sand eels.
5. The Black Guillemot has been protected in Iceland all year around since 2017 as the population has decreased for the past years.