Black-legged Kittiwake (Rissa tridactyla)

The Black-legged Kittiwake is a smaller gull. It is mostly pure white, small pointed bill, short black leggs, grey back and wings and most important: black beady eyes. This gull owes excellent flying abilities and can fly at extreme speed, even faster than the Northern Gannet, at least from my point of view.

Spends most of the year out on the Atlantic and only returns to shore for breeding. Breeds colonial on cliff ledges. The southernmost colonies are in northern Spain and in Portugal. A colony also exists on the German island of Heligoland in the southern North Sea (German Bight).

Description - Characteristics: Black-legged Kittiwake

Breeding – Clutch – Measurements – Habitat – Diet - Threats

Taxonomy:

Order: Charadriiformes

Family: Laridae

Genus: Rissa

Species: Black-legged Kittiwake

Scientific Name: Rissa tridactyla

Names and Synonyms of the Black-legged Kittiwake

Name in German: Dreizehenmöwe

Name in Czech: Racek tříprstý

Name in Slovak: Čajka trojprstá

Name in Hungarian: Csüllő

Name in Croat: Troprsti galeb

Name in French: Mouette tridactyle

Name in Spanish: Gaviota Tridáctila

Name in Portuguese: Gaivota-tridáctila

Name in Dutch: Drieteenmeeuw

Name in Italian: Gabbiano tridattilo

Name in Iceland: Rita

Name in Faroer: Rita, Ryta

Name in Greenland: Nowyavah, Taateraaq

Name in North Sami: Skierru

Name in Finnish: Pikkukajava

Name in Danish: Ride

Name in Swedish: tretåig mås

Name in Polish: Mewa trójpalczasta

Name in Russian: Моевка

Name in Japanese: ミツユビカモメ

Distribution – Movements – Habitat - Behaviour

Distribution: Circumpolar distribution, holarctic distribution at the shorelines of temperate zones and down south to 47° N. Also high arctic. In Europe from southwest to northwest. In the northwest only on Heligoland and in northern Denmark. Also on Greenland, Iceland, from western Russia to east Siberia, Alaska and Canada.

Movements: European breeders usually live in the North Atlantic, from the pack ice edge down south to the Sargasso Sea. Breeders from Greenland move to west Europe.

Wintering: most important winter areas are: from the North Atlantic pack ice edge southwards to the Sargasso Sea, Azores, western Mediterranean, eastern Mediterranean to Aegian Sea; Western Europe, Ireland (Republic), Great Britain, shorelines of Belgium, the Netherlands, Germany and Denmark (Wadden Sea).

Behaviour: The Kittiwake is fully adapted to a life on the ocean, only returning to land for breeding. Colonial breeder on cliffs and on small rocky islands. Rare winter guests inlands. Activities both diurnal and nocturnal. During breeding feeding flights mostly at night.

Measurements

Size: 37-42 cm

Weight:

♂: 350-500 g

♀: 310-470 g

Wingspan: 91-120 cm

Wing:

♂: 29.0-32.6 cm

♀: 27.9-31.8 cm

Breeding

Maturity: first appearance in colony from 2nd to 7th year. First breeding between 3-8 years.

Mating Season: monogamous seasonal breeding pair. Mating in colony, initiated by ♂. Re-mating with previous partner possible.

Clutches per breeding season1 clutch

Breeding: Begin of laying at centre of colony as of early May. More northern breeders from mid May to early June. On the peripheries of the colony laying starts usually 3.5 days later. Laying during day and night. Breeding between May and July

Nest: Earth and mud form the foundations of the nesting site only sparsely lined with material assembled in the surroundings. Nest building starts long before laying. Nest sits on cliff ledges and small outcrops. On the bird cliff Kittiwakes usually nest above the Black Guillemots and Cormorants.

Clutch: (2-) 2 (rarely -3) eggs

Eggs: crème-coloured broad-oval mostly fleckless egg, though speckled eggs are not uncommon.

Egg Measurements:

Length: 47.1-61.5 mm

Width: 34.5-44.5 mm

Ø: 54.6x40.1 mm (n=479)

Egg weight: 40.0-63.0 g

shell weight: 2.33-3.68 g; Ø 2.92 g g

Recurrent Clutch: possibly when clutch is lost during early days.

Laying Interval: 48 hours.

Begin of incubating: after first egg.

Incubation: 25-32 (35) days, both parents share the task of incubating. It takes 27.2 ±0.7 days from laying the last egg to the last chicken hatching

Hatching: The interval between first and second chicken is 1.3±0.7 days. It takes 2.3±0.97 days from first crack in the shell to first piercing the first hole into the shell; from there to final hatching it takes another 1.0±0.62 days .

Fledging: after 42 days the juvenils finally leave the nest, both parents care for the nestlings.

Dependency: After 30 days have only little ability to fly; after 34-36 days they have gained full flight ability. After leaving the nest juveniles are fully independent

Miscellaneous

Food: small fish, sandeels mollusks, crustacean.

Longevity: The oldest known ringed bird of a Kittiwake reached an age of 28 years and 5 months.

Mortality: From all layed eggs only 24 % of the juveniles reach the 5th year, whereas adult Kittiwakes have a survival rate of c. 86% per annum.

Threats: Large Gulls, disturbances at the colony, overfishing of the seas, fishing and processing of small fish such as sandeels, leading to a massive reduction in available food. Also perishing in fishing nets. Absorption of heavy metals from dietary sources. General deterioration of habitats.