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Boreal owl

 

 

Meeting boreal owls is most common during the autumn migration period: until the end of October. The migrants arrive from either the north or east, and in some years it may be classed as an invasion. In Finland they are quite numerous, about 5000 breeding pairs, in Estonia only a few hundred pairs. They are inhabitants of old forests. The migrants are females and young birds since older males largely stay in the nesting areas (they are familiar with the landscape and foraging conditions around the nest, and  a cavity nester must be able to defend the nest hollow all year round).

 

A boreal owl is only slightly larger than a pygmy owl, the size of a large thrush but with a large round head that adds to its bulk. Body length about a quarter of a metre, the males weigh just a little over a hundred grams, females half as much more (for owls this is the rule). Wing span half a metre, females a little more. The overall impression of the plumage is brown,  but back and wings are mottled with paler flecks. Underparts in reverse, light with brown flecks. Yellow eyes in light eye discs and a yellow beak – their faces always have a look of ”wonder”. A boreal owl’s legs, with black claws, are feather-covered.

 

It has a night-time lifestyle but on migration becomes active already when dusk arrives. In daytime it hides in a dense spruce stand. The little owl hunts in forest clearings for bank voles, voles and shrews and to a smaller extent migrating passerines that have stopped for the night.

 

The number of boreal owls that nest in Estonia is decreasing, there are ever fewer of them. There is a lack of nest hollows (boreal owls use nests made by black woodpeckers). However, the abundance of the bigger, more aggressive and stronger Ural owls may also contribute (up to a couple of thousand pairs nest in Estonia) because their menu in the forests is similar. Another enemy is the pine marten, whose numbers also have increased.

 

In Finland nest boxes are built for these hidden sympathetic owls, in Estonia this is not yet the custom….