Have you ever gone on a walk or a bicycle tour by our biggest lake, or went canoeing on its surface and heard a sound, reminiscent of the noise that is made when you blow into an empty bottle? The deep “BOOOH”, that can be heard up to 5 km away, is the call of the male bittern. We know very little about this bird, we are only certain that it is highly endangered.
The bittern (Botaurus Stellaris) is the target species of project LIFE STRŽEN. LIFE financial mechanism prioritizes project activities that aim to improve the habitat and living conditions for the survival of this Natura 2000 species.
The bittern is a wading bird in the bittern subfamily of the heron family. It spends most of its time in the cover of reeds, which hide it well, due to the camouflaging patterns of its feathers. This makes spotting it a rare occasion, despite its relatively large size. Its presence is usually apparent because of the male’s call, coming out of the reedbed.
The bittern has strict requirements when it comes to choosing its nesting ground. It is especially shy during the nesting period. It nests in vast reedbeds, since it needs a lot of peace to raise its young. It is most active at dusk, when it is looking for food by the water bank. It hunts animals, smaller than itself, such as fish, amphibians, reptiles, birds’ young, small mammals and large invertebrates, like beetles, dragonflies and their larvae.
The bittern is an umbrella species of birds residing in reedbeds and similar wetland plant communities. This means that improving the habitat of the bittern will also have a positive impact on other bird species from the red list, such as the spotted crake, little crake, water rail, common snipe and the great reed warbler.
Cerknica Lake is the only nesting area of the bittern in Slovenia, so it is imperative to improve the nesting conditions on the lake in order to conserve this species in our country. Within the scope of project LIFE STRŽEN we will establish a quiet zone and suitable living conditions for the bittern, which will enable undisturbed nesting of the species.
The quiet zone will be established in the vicinity of the restored meanders of Stržen in the area Ključi. The strictest restriction in the quiet zone will be the ban on fishing on this part of the watercourse, which is managed by The Fisheries Research Institute of Slovenia. However, significant changes aren’t expected, since the restoration of Stržen in the area Beli Breg will expand the fishing zone by the same length as it will be reduced in Ključi.
We will place lookout infrastructure on the outskirts of Cerknica Lake with the goal of redirecting visitors away from the area of the quiet zone. An education trail will be set up, linking the lookout points, which will allow visitors to experience nature with wonderful views of this exceptional area.
The current management plan for the land of Cerknica Lake is focused on the conservation of the corncrake, an endangered bird species. This way of managing land is not suitable for the bittern, however, since it requires extensive areas of reeds with open water surfaces. For this reason, Notranjska Park doesn’t mow certain areas, thus providing favourable living conditions for both Natura 2000 species.
Some interesting facts about the bittern:
- The low-frequency call of the male can be heard up to 5 km away;
- males living in large swamps can mate with several females, but they generally don’t nest in colonies;
- the bittern looks like a cross between the heron and the owl;
- the wing span of a grown bird measures around 130 cm and a stretched-out bird is about 75 cm long;
- the bitterns from this area are migratory birds and migrate to warmer climates when it gets cold;
- it is most endangered by the disappearing of its habitat due to drying of the land and because of disturbances during nesting season.