email a friend
printable version
Location Poland, podlaskie
Central coordinates 23o 40.00' East  53o 4.00' North
IBA criteria C1, C6
Area 5,168 ha
Altitude 146 - 160m
Year of IBA assessment 2010

Ogólnopolskie Towarzystwo Ochrony Ptaków

Site description The site consists of a large basin covered by a thick layer of peat. The basin drains into the upper course of the Supraœl river, which traverses the northern part of the site. Most of the area has been drained by man, but in many places there are still mires. The central part of the basin is occupied by fens (mainly sedge-beds, occasionally reedbeds Phragmites), while the southern part is raised bog, with marshy forest and a variety of bog mosses. There are two small lakes, Gorbacz and Wiejki. The marshy forest is dominated by birch Betula and pine Pinus, with alder Alnus scrub also common.

Key Biodiversity A total of 105 species have been recorded breeding. Species of global conservation concern that do not meet IBA criteria: Haliaeetus albicilla (one bird on passage), Crex crex (20-40 breeding birds).

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Corncrake Crex crex breeding  2009  200-270 males only  medium  C1  Least Concern 
Great Snipe Gallinago media breeding  1989-2002  9-17 males only  C6  Near Threatened 

IBA Monitoring

2009 high not assessed low
Medium - based upon reliable but incomplete / partially representative data

Agriculture and aquaculture annual & perennial non-timber crops - small-holder farming happening now small area/few individuals (<10%) slow but significant deterioration low
Biological resource use hunting & collecting terrestrial animals - intentional use (species being assessed is the target) likely in short term (within 4 years) some of area/population (10-49%) slow but significant deterioration medium
Energy production and mining mining and quarrying happening now some of area/population (10-49%) slow but significant deterioration medium
Natural system modifications dams & water management/use - dams (size unknown) happening now majority/most of area/population (50-90%) moderate to rapid deterioration high
Natural system modifications other ecosystem modifications happening now some of area/population (10-49%) moderate to rapid deterioration high
Pollution domestic & urban waste water - type unknown/unrecorded happening now some of area/population (10-49%) slow but significant deterioration medium

Forest Broadleaved deciduous woodland  800 800 100 moderate (70-90%) near favourable
Grassland   2500 2500 100 poor (40-69%) unfavourable

Crex crex Corncrake 270 270 males only 100 not assessed

Most of site (50-90%) covered (including the most critical parts for important bird species)  No management planning has taken place  Substantive conservation measures are being implemented but these are not comprehensive and are limited by resources and capacity  low 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Gorbacz Nature Reserve 114 unknown 114  
Gorbacz NR (Peatbog Reserve) Nature Reserve 114 protected area contained by site 114  
Park Krajobrazowy Puszczy Knyszyñskiej Landscape Park 73,094 unknown 0  


IUCN habitat Habitat detail Extent (% of site)
Forest Alluvial and very wet forest; Broadleaved deciduous woodland; Mixed woodland  15%
Grassland Humid grasslands; Mesophile grasslands  50%
Wetlands (inland) Fens, transition mires and springs; Raised bogs; Rivers and streams; Standing freshwater  30%
Artificial - terrestrial Arable land; Highly improved re-seeded landscapes  5%

Land use

Land-use Extent (% of site)
agriculture 55%
forestry 5%
not utilised 40%
hunting -

Protection status National Low International None114 ha of IBA covered by Nature Reserve (Gorbacz [Peatbog Reserve], 114 ha).

Contribute  Please click here to help BirdLife conserve the world's birds - your data for this IBA and others are vital for helping protect the environment.

Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Gródek-Michalowo basin. Downloaded from on 26/10/2016

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