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Location Poland, warminsko-mazurskie
Central coordinates 21o 35.00' East  54o 18.00' North
IBA criteria C6
Area 2,308 ha
Altitude 64 - 80m
Year of IBA assessment 2010

Ogólnopolskie Towarzystwo Ochrony Ptaków

Site description The site encompasses the nutrient-rich lake and adjoining wet forest and open areas with many swamps. Most of the previously pastured areas are no longer used, and have reverted to swamps occupied by young alder Alnus wood or sedge meadows. Open water is not extensive, and the greater part of the lake is covered by reedbeds Phragmites. There are seven islands (all forested). The Oœwinka river (tributary of the £yna) rises from the lake.

Key Biodiversity Breeding species of global conservation concern that do not meet IBA criteria: Haliaeetus albicilla (one pair), Crex crex (four pairs). A total of 126 species have been recorded.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Little Crake Zapornia parva breeding  2007-2009  70-90 males only  medium  C6  Least Concern 
Black Tern Chlidonias niger breeding  2007-2009  40-45 breeding pairs  good  C6  Least Concern 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Jezioro Siedmiu Wysp Nature Reserve 999 protected area contained by site 1,000  
Jezioro Siedmiu Wysp Wetlands of International Importance (Ramsar) 999 protected area contained by site 1,007  


IUCN habitat Habitat detail Extent (% of site)
Forest Broadleaved deciduous woodland; Mixed woodland; Native coniferous woodland  15%
Grassland Humid grasslands; Mesophile grasslands  15%
Wetlands (inland) Fens, transition mires and springs; Raised bogs; Rivers and streams; Standing freshwater; Water fringe vegetation  40%
Artificial - terrestrial Arable land; Ruderal land  30%

Land use

Land-use Extent (% of site)
agriculture 40%
forestry 12%
nature conservation and research 40%
not utilised 10%
hunting -

Protection status National Partial International Partial1,007 ha of IBA covered by Nature Reserve (Jezioro Siedmiu Wysp [Bird Reserve], 1,007 ha). 1,007 ha of IBA covered by Ramsar Site (Jezioro Siedmiu Wysp, 1,007 ha).

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Oswin site. Downloaded from on 25/10/2016

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