Larus cachinnans in Poland

(last update: August 01, 2021)

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cachinnans in Poland

National distribution

Zastów Karczmiski
Kępa Nadbrzeska
Jeziórko
Jankowice
Mietków Reservoir & Chwałów
Kozielno & Topola Reservoir
Mokrzec
Wytyckie Lake
Dankowice / Foskowiec Pond
Czorsztyn Reservoir
Kuźnica Warężyńska / Pogoria
Dwory

small colonies or single sites

Caspian Gull cachinnans: Mietków Reservoir & Chwałów

Mietków Reservoir & Chwałów: 50°57’04.1″N 16°36’06.5″E.

coordinators:
Paweł Grochowski,
Joanna Pomorska-Grochowska,
Klaudia Litwiniak,
Marcin Przymencki
For questions mail to: merula@wp.pl, marcin.przymencki@wp.pl

Habitat: 

Mietków is a dam reservoir on Bystrzyca river, located at Świdnicka Plain in SW Poland (Lower Silesia voivodeship), about 45 kilometres south-east of Wrocław. Nearest towns and villages are Mietków, Borzygniew, Domanice, Chwałów, Imbramowice, Maniów and Maniów Mały. It is the largest water reservoir in the area.

The construction was finished in 1986. In 2007 the Minister of Environment of Poland established Mietków Reservoir as the Special Protection Area based on Birds Directive in the law of European Union (PLB020004). This protects birds like Black-headed Gull, Mediterranean Gull, Common Tern and Shelduck.

Gulls started nesting here on a few gravel islands covered by grass and willows, although on some islands the vegetation includes higher trees as well (alders). The islands are located in south-western part of the reservoir, near the Bystrzyca river mouth. From year to year, the number of islands with gull colonies varies, mainly due to changing water level in the reservoir.

Breeding species:

• Larus cachinnans
• Larus michahellis
• Chroicocephalus ridibundus
• Ichthyaetus melanocephalus

Caspian Gulls have bred here since 1998. In the early years, a few pairs of Herring Gulls started breeding too, but abandoned the location soon. Nowadays the number of breeding pairs varies, but on average there are 200 pairs. Dominant species is Caspian Gull, but some Yellow-legged Gulls breed here too, although exact numbers are not known due to difficult conditions to observe the colony. We suppose 2-5 birds with michahellis phenotype to breed here every year, usually in mixed pairs. There were some cases of breeding Lesser Black-backed Gulls here too: in 2009 and 2010 they formed mixed pairs with Caspian Gull and Yellow-legged Gull, and in 2021 the first ‘pure’ pair of Lesser Black-backeds started a nest.

Black-headed Gulls breed in vast numbers, counts exceed the 3,000, and here and there Mediterranean Gulls have their nests. both species usually nest on the same island with the large gulls. At Chwałów pond, one pair of Mew Gulls Larus canus breeds every year.

Paper on breeding biology at Mietków.

Annual numbers for Mietków Reservoir:

Recovery map for Mietków Reservoir:

Caspian Gull cachinnans P:S66 1CY, October 22 2018, Katwijk, the Netherlands. Picture: Mars Muusse.

Could this be a hybrid?