Calender

JANUARY

Generally cold and snowy. Good period to taste real eastern winter with deep snow cover. Numerous invasion species as Waxwings/Redpolls/Snow Buntings occur in countryside. Wandering Eagles - White-tailed and Golden possible, Rough-legged Buzzard usually common.

FEBRUARY

Passage of Shore Larks and first spring migrants - Lapwings, Sky Larks. Start of Eagle Owl and other owls activity.

MARCH

Good month for Woodpeckers, including White-backed and Three-toed (Bialowieza Forest). Waterfowl migration is on the move in Biebrza and Narew Valleys. Thousands of geese and swans stop here for feeding during migration. Some late winter birds still remain here: Rough-legged Buzzard, Waxwing, Redpoll. Owls start their activity - Tengmalm at nights with calm weather, Pygmy durign warmer evenings.

APRIL

Migration month with still thousands of Geese and first Ruff arriving. Woodpeckers and Owls active in forests.

MAY

Most popular month for visiting. The weather may be surprisingly hot, but also sometimes rainy. Thousands of passing Ruffs, Terns in river Valleys.
Forests
Good time to watch Woodpeckers feeding youngs - White-Backed, Middle Spotted, Syrian.
Marshes
Late migrants arrive - Aquatic Warbler at the beginning of May, Marsh Warbler after half of the month. Late afternoon or evening are very good for those species. Marsh Terns numerous - start nesting and are present in many places.

Many rarities are recorded in May also due to many visitors coming:
Long-tailed Skua - May 2010
Slender-billed Gull
Buff-breasted Sandpiper
Pallid Harrier (breeding attempt in 2008) 

JUNE

Good month for Warblers: Barred, Greenish, Blyth's Reed and more common ones: Aquatic, Savi's, River and Grasshopper.

JULY

Quite hot (20-30 C) and sometimes rainy month, though with numerous breeding birds active while feeding youngs. Warblers still singing, Terns feeding chicks.

AUGUST

In the middle of the month groups of Storks and Cranes start moving southwards. Flocks reaching hundreds of birds start early morning from roosts and search for strong currents taking them further on the migration route. Shorebirds also show up in wet places eg muddy edges of fish-ponds or riversides (Biebrza/Narew) or lakes (Siemianowka Reservoir). In forests in the second half of the month owls start their autumnal activity (Pygmy, Tengmalms).

SEPTEMBER

Raptor migration - Eagles (Lesser Spotted) and other raptors (Osprey, Honey Buzzard) start flying south. They pass over river valleys and reservoirs and may be easily observed, sometimes in small groups. Siemianowka Lake hosts various waders including rarities like Marsh Sandpiper or Broad-billed Sandpiper. On cold nights first Red Deer start hooting, accompanied by dawn whistling of Pygmy Owls. Big flocks of Cranes may gather in Biebrza Marshes at their stopovers.

OCTOBER

First frosts come in this month and trees become yellow-red. Still rather sunny, without rainy weeks. Tundra migrants arrive - Rough-legged Buzzards, Waxwings, Shore Larks. Raptors passing - Buzzards, Merlin, Hen Harrier.
Rarities recorded: Pectoral Sandpiper, Hawk Owl

NOVEMBER

Most of the trees already without leaves, flocks of Waxwings numerous in towns and villages. Wintering raptors roam in Biebrza and Siemianowka - White-tailed Eagles, Rough-legged Buzzards, Hen Harriers.

DECEMBER

Usually snowy and quite cold. Temperatures below zero, sometimes down to -20 C. Most of the lakes and rivers covered with ice.
Numerous winter visitors include Rough-legged Buzzard (common), Waxwing (common), Golden Eagle (singles, increasing).
Northern rarities possible: Snowy Owl (large marshes ans meadows), Hawk Owl.

Good period to watch wild Bisons which leave forests and wander in the fields.