UBPRC – Ukrainian Birds of Prey Research Centre

Wintering of the Long-eared Owls in Ukraine

The Long-eared Owl (Asio otus) is one of the most common and widespread species of owls in Ukraine. However, by the moment there had no works generalizing the data on its numbers and distribution in the country during the winter period. It is exactly the issue this post is dedicated to.

To analyze the number and distribution of the Long-eared Owls in Ukraine there have been used literary sources*, personal observations of authors and communications of other ornithologists. The data mainly for the years 2000-2009 were analyzed. However, for particular territories also observations of the previous decade were used. The list of identified wintering sites of the Long-eared Owls can be found in the attached file [in Russian].

As it is known, the Long-eared Owls typically form concentrations in winter on day roosting sites, numbering dozens and even hundreds of birds (Priklonsky, Ivanchev 1993). However, the adaptive significance of this phenomenon is not completely revealed (Pukinsky, 1977).

The wintering sites of the Long-eared Owls in Ukraine cover practically the whole territory, except for mountainous regions of the Carpathians and Crimea. In the Carpathians, wintering grounds of this species were rarely observed at low altitudes, where the birds had penetrated along the wide river valleys. In particular, in the winter of 1989 the bird concentration was observed in Yaremcha City (ca. 650 m above sea level). The exteme points of wintering sites, where the birds approach to the foothills of the Crimea, are the village of Urozhayne (Simferopol district), the village of Zuya (Bilohorsk district) (V.N. Kucherenko, pers.comm.).
Distribution of wintering sites of the Long-eared Owls is rather uneven. The concentration of species is mainly observed in the cosy areas, relatively sheltered from wind. Most often there are tree plantations in the residential areas, rarer – outside of them. Mass day roosts of owls are formed in a variety of coniferous trees. Therefore, roost sites are largely determined by presence of such plantations. In addition, due to the growing number of the Goshawk, which hunt on them, the settlements are more secure territory for these owls.
Depending on the attractiveness, roost sites can be used by birds as short-term, or during the entire winter period, or annually for many years. There are also published data that permanent places of wintering are mainly formed by adults and non-permanent – by young birds. This is explained by the fact that the permanent wintering grounds consist of sedentary (nonmigratory) birds, and irregular winterings are formed by juveniles who fulfill far dispersion flights (Galeotti et al. 1997).
Some places of wintering the Long-eared Owls in Ukraine use for decades. For example, for at least 20 years the Long-eared Owls winter in Velykoanadolsky Forest (Donetsk region). (D.V.Pilipenko, pers. comm.). In the village of Goloskov (Letychiv district, Khmelnitskyi region) wintering of this species is known for at least 15 years (V.O.Novak, pers. comm.).
The highest number of mass wintering sites of the Long-eared Owls is located in the south of Ukraine (figure). In this region, we know of 11 locations where, at least once, it was recorded 100 or more individuals simultaneously. The dendropark of Askania Nova Biosphere Reserve is probably among the places which hold most stable and highest number of owls. One case of mass wintering in recent years was observed in the Transcarpathians, and another – in the city of Kamenets-Podolskyi, possibly due to the milder climate in this period. In all other regions of Ukraine there are known six sites of mass wintering of the Long-eared Owls, which is probably associated with more severe climatic conditions in winter. For justice’s sake, it should be noted that distribution of known wintering sites in the territory of Ukraine is often determined by the extent of investigation of individual regions.
In general, the number of the wintering Long-eared Owls is characterized by significant annual fluctuations, because of which this species consider as invasive (Newton 2008). The main causes of fluctuations in numbers are weather conditions and abundance of rodents as the main prey. In addition, the population of owls can significantly decrease after severe winters. The maximum number of birds in the southern regions is recorded in more severe winters, with high numbers of rodents.
The number of the wintering Long-eared owls in Ukraine is not exactly known. I.M. Gorban (2004), basing on the analysis of numerous publications, estimated it at 12000-25000 ind. Basing on the currently available data we can say that, supposedly, the above-mentioned number corresponds to the real situation.

Acknowledgments. The authors express their deep appreciation to ornithologists who provided unpublished materials about wintering Long-eared Owls: A.M. Arkhipov, M.V. Bannikov, N.N Borisenko, M.V. Vasilenko, M.F. Veselsky, V.V. Vetrov, I.V. Davydenko, T.M. Kornienko, N.P.Knish, S.V. Kochanov, V.N. Kucherenko, A.A. Matveichuk, Yu.V. Milobog, V.O. Novak, P.S. Panchenko, Z.I. Petrovich, D.V. Pilipenko, G.I. Polosmak, I.M. Polyushkevich, L.V. Pokritok, A.V.Sagaidak, O.A. Svinareva, O.L. Skid, I.V. Skilsky, M.V. Slyusar, Yu. Sumsky, A.Sypko, KA. Redinov, O.A. Formanyuk, S.A. Shevtsov, O. Yakubenya.

*Literature: Andryushchenko et al. 2001; Andryushchenko et al. 2002; Ardamatskaya 2001; Atamas, Tovpinets 2006; Afanasyev 1998; Buchko 1999; Veselsky, Tsitsyura 2004; Gavrilenko et al. 2002; Gavrilyuk, Gryshchenko 2001; Gavris et al. 2007; Gorlov et al. 1996; Drebet 2005, 2007; Edynak 1999; Zhmud 1999; Zaitseva, Drebet 2007; Kapelyuh 2008; Kapelyuh, Guziy 2000; Ornithological observations …, 1993; Moskalenko 2000; Novak 2003; Pirogov 1991; Popenko 2004; Potish 1994; Redinov 2004; Redinov 2006; Redinov, Korzyukov 1999; Rogovy 1998; Rusev 2000; Rusev et al. 1996; Rusev et al. 1998; Rusev et al. 2001; Skvortsova 2006; Zaika, 2009.

If you have any additions to the known wintering sites of the Long-eared Owls in Ukraine, please contact us. We will be grateful for the information.

Maxim Gavrilyuk, Yury Kuzmenko, Andrey-Taras Basta