Видовой состав хищных птиц Бузулукского бора (Оренбургская и Самарская области, Россия) по результатам наблюдений в прошлом и настоящем

Abstract

Buzuluk pine forest is a unique pine massif with a total area of 111,118 hectares, which is located entirely in the steppe biome on the border of the Orenburg and Samara regions, in the southeastern part of the Russian Plain. This report provides some information about threatened and endangered raptors of the Buzuluk pine forest for a relatively long period of time. It uses data by scientist and ornithologist E.P. Knorre collected between 1928 and 1941, present time observations carried out since 2000 to the present, and published data by other researchers who have visited Buzuluk pine forest starting from the beginning of the 21st century. Most observations by E.P. Knorre were associated with the Pine Barrens Experimental Forestry in the Orenburg region, where “Buzuluk pine forest” Nature Reserve (10,503 hectares) existed at the time. In his unpublished monumental report “Qualitative inventory of birds and animals of the Buzuluk Pine Forest State Nature Reserve”, discovered in the archive of the current “Buzuluk Pine Forest” National Park relatively recently, E.P. Knorre listed the following raptor species found in Buzuluk Pine Forest: Common Kestrel Falco tinnunculus (breeding) Red-Footed Falcon Falco vespertinus (breeding) Eurasian hobby Falco subbuteo (breeding) Saker Falcon Falco cherrug (breeding) Osprey Pandion haliaetus (highly likely breeding) European Honey-Buzzard Pernis apivorus (breeding) Black Kite Milvus migrans (breeding) White-Tailed Sea-Eagle Haliaeetus albicilla (breeding) Short-Toed Snake-Eagle Circaetus gallicus (breeding) Western Marsh-Harrier Circus aeruginosus (breeding) Pallid Harrier Circus macrourus (breeding) Eurasian Sparrowhawk Accipiter nisus (breeding) Northern Goshawk Accipiter gentilis (breeding) Eurasian Buzzard Buteo buteo (breeding) Rough-Legged Buzzard Buteo lagopus (wintering) Greater Spotted Eagle Aquila clanga (breeding) Eastern Imperial Eagle Aquila heliaca (breeding) Golden Eagle Aquila chrysaetos (breeding) Eurasian Scops Owl Otus scops (breeding) Eurasian Eagle Owl Bubo bubo (breeding) Tawny Owl Strix aluco (breeding) Ural Owl Strix uralensis (breeding) Little Owl Athene noctua (common in autumn, the status is unclear) Northern Long-Eared Owl Asio otus (breeding) Short-Eared Owl Asio flammeus (breeding) Since the beginning of the 21st century, occurrence of most raptor species listed in report by E.P. Knorre was confirmed in the modern period of observations in Buzuluk Pine Forest. Nevertheless, such raptor species as Common Kestrel, Red-Footed Falcon, Saker Falcon, Osprey, Short-Toed Snake-Eagle, and Pallid Harrier were not recorded. Western Marsh-Harrier that once bred here was not found on the internal water lakes and swamps of the Buzuluk Pine Forest. As for the Strigiformes, Tawny Owl, Ural Owl and Northern Long- Eared Owl were recorded more frequently today. The previously breeding Eurasian Scops-Owl and Short-Eared Owl in the inner sections of the pine forest were not recently found here. Present-day breeding of Eurasian Eagle Owl requires additional confirmation. The finds of Little Owl, included in the Knorre’s report as autumn migrant, have not been confirmed yet. At the same time, new raptor species have been registered in the Buzuluk Pine Forest. These include Peregrine Falcon (Falco peregrinus; single individual was observed in summer: Barabashin, 2001), Hen Harrier (Circus cyaneus; a pair of birds in May: our data), Montagu’s Harrier (Circus pygargus; single bird in May: our data), Levant Sparrowhawk (Accipiter brevipes; single bird in May: Morozov, Kornev, 2009). According to our observations, the wellbeing of such species as Greater Spotted Eagle, White-Tailed eagle, Golden Eagle, Short-Eared Owl, Western Marsh-Harrier, Montagu’s Harrier was influenced by the ongoing climate warming in the Buzuluk Pine Forest area, which was evident from raising average annual air temperatures and decreasing precipitation. According to observations by E.P. Knorre, another serious limiting factor in the past was transformation of the forest under the influence of extensive fires and uncontrolled logging of trees. Logging and fires in pre-Soviet times led to appearance of huge empty spaces, which were then penetrated by steppe vegetation from adjacent steppe areas. Steppe formation was responsible for the appearance of such species as Common Kestrel, Red-Footed Falcon, Pallid Harrier, Eastern Imperial Eagle across inner forest areas for some time. In the 1950s, the mass pine tree plantings and increased fire control led to restoration of the forest integrity and at the same time to disappearance of Common Kestrel, Red-Footed Falcon, Pallid Harrier, relocation of breeding pairs of Eastern Imperial Eagle to outer rims of the forest.