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Location Bulgaria, Montana
Central coordinates 23o 5.12' East  43o 47.45' North
IBA criteria A1, B2, C1, C6
Area 475 ha
Altitude 30 - 39m
Year of IBA assessment 2005

Bulgarian Society for the Protection of Birds

Site description The former Orsoya marshes, on the bank of the River Danube, which have been converted to fish-ponds and overgrown by stands of Phragmites and Typha. In deep parts of the ponds there are water-lilies Nymphoides and Nymphaea. The ponds are surrounded by meadows, scrub and trees. Land-uses include fish-farming, haymaking, and hunting.

Key Biodiversity This site is important for species of global conservation concern (Aythya nyroca and Phalacrocorax pygmeus), and supports large numbers of breeding Ixobrychus minutus. Breeding species of global conservation concern that do not meet IBA criteria: Crex crex (uncommon).

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Ferruginous Duck Aythya nyroca breeding  2004  12-30 breeding pairs  medium  A1, C1, C6  Near Threatened 
Ferruginous Duck Aythya nyroca passage  1996  48-79 individuals  good  A1, C1  Near Threatened 
Ixobrychus minutus breeding  1996  100 breeding pairs  good  B2, C6  Not Recognised 
Purple Heron Ardea purpurea breeding  1996  10 breeding pairs  good  C6  Least Concern 
Pygmy Cormorant Microcarbo pygmaeus passage  1996  40-180 individuals  good  A1, C1  Least Concern 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Orsoya Protected Landscape 150 protected area contained by site 150  


IUCN habitat Habitat detail Extent (% of site)
Forest Alluvial and very wet forest  5%
Grassland Humid grasslands  20%
Wetlands (inland) Standing freshwater; Water fringe vegetation  70%
Artificial - terrestrial Perennial crops, orchards and groves  5%

Land use

Land-use Extent (% of site)
fisheries/aquaculture 60%
hunting 70%
other 20%

Protection status National None International None

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Orsoya Fish-ponds. Downloaded from on 25/10/2016

To provide new information to update this factsheet or to correct any errors, please email BirdLife