The Eurasian pygmy owl (Glaucidium passerinum) is a member of the family Strigidae (true owls) and it is the smallest owl of Central Europe. Its size is about 16 –19 cm and it weighs less than 100 Gramms. Females are usually bigger than male individuals.
In Central and Northern Europe pygmy owls inhabit uplands, alpine or boreal regions where they prefer highly structured coniferous forests. Their main diet are little mammals and small birds and although their relative small size they can kill prey that is much larger. Eurasian pygmy owls are active in the twilight hours near sunrise and sunset, at night they normally rest and hide from enemies like i.e. tawny owls. Only in bright nights with full moon they can be heard from time to time. These owls are sedentary and defend their home ranges that extend up to 2.5 sqkm against fellow species very aggressively. They nest in old woodpecker holes and also hold several holes as a food store during the breeding season that last from early spring to May.
Often heard – barely seen
The call is very characteristic and can be heard within a distance of more than one kilometer. It usually consists of a chain of monotone fluted sounds with pauses of two seconds. The call of the female is higher in pitch but very similar. Further typical calls outside the mating season consist i.e. of a five to seven note rise on the pitch scale. The begging call of young pygmy owls is easily overheard because its pitch is very high. The call of Europe’s second smallest owl, the Eurasian scoops owl, sounds very similar. For the experienced ear it is a little bit more “nasal” and in contrast to its smaller sister from the north, this owl can only be heard at night.
An island in the North of Germany
In Germany pygmy owls are found in uplands like the Thuringian-, Bavarian- or Black Forest, the Harz National Park and in the mountain regions of the Alps. But between these territories and the boreal populations of Scandinavia there is also an insular occurrence that was overlooked for a long time: It is situated in Naturpark Südheide which is the southern part of National Park Lueneburg heath in Lower Saxony. With more than 200 breeding pairs this region is known as the centre of low-land populations of Eurasian pygmy owls in middle Europe. In Naturpark Südheide these birds found perfect conditions – the highly structured woods consist of old spruces with many woodpecker holes and hold a network of glades and forest tracks (for fire-fighting) where they can hunt for prey. Another important condition is the relative abundance of tawny owls, alongside sparrow hawks, one of the main enemies of pygmy owls.
On the rise but still threatened
In Germany and especially in Lower Saxony the number of pygmy owls is constantly growing. Although these birds are difficult to monitor, there are approximately 2500 – 3000 breeding pairs in Germany from which there is an estimated population of 200 pairs in Lower Saxony. Natural enemies are tawny owls, eagle owls, sparrow-hawks and pine martens (nest robbers), but the biggest threat for these owls is the destruction of habitats. Because of the climate change and for economic reasons modern forestry is nowadays counting more and more on pine trees instead of spruces which are essential for breeding. Old spruces with woodpecker holes are removed and former highly structured forests are optimized for mechanized wood chopping by planting trees of the same age.