Biebrza Marshes

The Biebrza Marshes fill a valley about 100 km (62 mi) long in north-eastern Poland, a basin formed during the Middle Polish and Baltic glaciations, where a large lake made by the waters of the ancient Neman once lay and peat has since built up 1 to 6 m (3 to 20 ft) thick. Around 1,000 km² (386 sq mi) of the valley is fen, raised bog and marsh, broken by low rises known as grądy, and it is one of the largest wildlife refuges in Europe. Most of it lies within Biebrza National Park, created in 1993 and, at 592.23 km² (228.66 sq mi), the largest national park in Poland; almost the whole course of the river, about 155 km (96 mi), runs through it. Over 250 bird species have been recorded, more than 80 per cent of those known in Poland, and the park is the largest refuge for elk in the country, with about 400 animals.

Background

The Biebrza Marshes fill the valley of the Biebrza river in north-eastern Poland, a wetland complex of river channels, lakes and wide marshes, with alder carr and other woods on the higher ground and peat bogs that have kept their natural state. Across the valley the habitats pass from riverside fen to raised bog and then wet woodland, and this sequence supports a wide diversity of wildlife. Over 250 bird species have been recorded, more than 80% of those known in Poland, and from early spring the courting birds draw birdwatchers from around the world. Most of the area lies within the Biebrza National Park, a Ramsar site.

Source: Wikipedia, "Biebrza Marshes"

What's there

• Trails and river trips - fourteen educational paths, among them the Kładka boardwalk and the Czerwone Bagno trail, 103.7 km (64.4 mi) of cycle routes and trips down the Biebrza.
• Elk - about 400 in the park, the largest refuge for the species in Poland; elk survived the mid-20th century here alone in the country and, once protected, spread back across Poland.
• The southern basin - the most natural part of the valley, 12 to 15 km (7.5 to 9.3 mi) wide, where the river meanders past the Ławki and Podlaskie marshes.
• The birds - the ruff, shown on the park's emblem, the aquatic warbler, the great snipe, cranes, curlews, white-winged and whiskered terns and the lesser spotted eagle, with black grouse and short-eared owls among the rarities.

When to go

The articles give no visiting season. Birdwatchers come from early spring, when the breeding birds begin their courtship, and the valley is also an important feeding and resting place for many birds on their yearly migrations. The marshes flood often; in April 2020 a low water level let a fire, started by grass burning, spread for over a week across about 5,280 ha (13,047 acres) by one count and at least 6,000 ha (14,826 acres) by another, and in April 2025 a fire burned about 450 ha (1,112 acres).

Good to know

After the 2020 fire, studies recorded marked falls in 14 bird species, the aquatic warbler among them; for that warbler the valley is of exceptional importance, and its survival may depend on the Biebrza sedge marshes staying as they are. The drained Wizna marshes at the southern end lie outside the national park. The park has been a Ramsar site since 1995 and, since 2010, an Important Bird Area of BirdLife International, and its headquarters stand in the grounds of the 19th-century Osowiec Fortress.

Nearby

The Biebrza joins the Narew at the southern end of the park. From the park headquarters at Osowiec, Goniądz is about 7 km east-north-east, Augustów about 47 km north-north-east, Narew National Park about 47 km south-south-east, Łomża about 49 km south-west and Białystok about 51 km south-east, all in a straight line.

Key facts