Lake Łuknajno is situated 5 km from Mikołajki. There are three watch towers around it from where water and marsh birds observation can be kept (the entrance to the towers is free). The lake is known to be a unique habitat of a mute swan. Every year, from a dozen to several dozen swan couples nest here. This area has been protected since 1937. In 1947 Lake Łuknajno with an adjacent Czarne Bagno swamp was approved to be an ornithological nature reserve of Lake Łuknajno. Due to its exceptional scientific value, it has been internationally protected under the UNESCO-MAB programme as a biosphere reserve since 1976, in order to preserve the habitat of the mute swan. A total area of the lake amounts to 680 ha. It is connected to Lake Śniardwy with a narrow canal. Lake Łuknajno is an eutrophic lake with a wide stripe of reeds that slowly overgrows with plants. There is extensive low peat around the lake, partly occupied by meadows and willow thickets.
