Central Europe's largest area of natural bog or wetlands is protected by Biebrza (byehb-zhah) National Park. It's Poland's largest park, stretching more than 100km from close to the Belarus border to the Narew River near Tykocin. It offers some vast areas of serene natural beauty. Myriad hiking trails and kayaking courses wend through one of Poland's best places to spot birds. Although you can spend days here, you can easily dip into the natural beauty near the village of Osowiec-Twierdza.
The varied landscape consists of river sprawls, peat bogs, marshes and damp forests. Typical local flora includes numerous species of moss, reed grass and a range of medicinal herbs. The fauna is rich and diverse, and features mammals such as wolves, wild boar, foxes, roe deer, otters and beavers. The king of the park, however, is the elk: about half of the country's population, around 600 animals, live within the park's borders. Birdwatchers flock to Biebrza to glimpse the 270 or so bird species (over half of all species recorded in Poland) that call the park home.
The park can be broadly divided into three areas: the Northern Basin (Basen Północny), the smallest and least-visited area of the park; the Middle Basin (Basen Środkowy), stretching along the river's broad middle course and featuring a combination of wet forests and boglands; and the equally extensive Southern Basin (Basen Południowy), where most of the terrain is taken up by marshes and peat bogs.
The showpiece is the Red Marsh (Czerwone Bagno) in the Middle Basin, a strictly protected nature reserve encompassing a wet alder forest that is inhabited by about 400 elk.
With over 200km of water trails criss-crossing the length of the valley, the best way to explore the park is by boat. The principal water route flows from the town of Lipsk downstream along the Biebrza to the village of Wizna. This 140km stretch can be paddled at a leisurely pace in seven to nine days. Campsites along the river allow for overnight stops, and food is available in towns on the way.
The visitor information centre in Osowiec-Twierdza can provide maps and information. You can also hire a kayak for a few hours or a day and cover part of the route; a handy two-hour stretch runs from Goniądz to Osowiec-Twierdza (kayaks can be rented from Goniądz's camping ground). Access to kayak trails costs 6zł for adults and 3zł for students and children per day on top of hire charges.
Despite its overall marshy character, large parts of the park can be explored by bicycle and on foot. About 250km of signposted trails have been tracked through the most interesting areas, including nearly 50km through the Red Marsh alone. Dikes, boulders and dunes among the bogs provide access to some splendid birdwatching sites.