Nesting of Tree Sparrow Passer Montanus in the Nest of Common Buzzard Buteo Buteo

The Tree Sparrow nests mainly in tree holes, nestboxes, street-lamps, buildings, earth banks and rocky crevices (Nankinov 1984, Cramp 1998) .It also occupies the foundations of nests of other birds .Broods were recorded also in nests of other bird species: Magpie Pica pica, Grey Heron Ardea cinerea, White Stork Ciconia ciconia, White-tailed Eagle Haliaeetus albicilla, Osprey Pandion haliaetus, Black Kite Milvus migrans and crows Corvidae (Makatsch 1957, Cramp 1998, Bocheński 2005) .This note reports observation conducted in the breeding season of 2008, in a farmland near Leszno (51 o 51'N; 16 o 34'E), western Poland .In this area Common Buzzard nests mainly in pine woods and in midfield small forests .I found a nest of the Common Buzzard placed in a row of Black Alder Alnus glutinosa trees .It was located 350 m from the nearest buildings of Dąbcze village and surrounded by arable fields, meadows and shrubs .The nest was situated 6 m above the ground and was visible from quite long distance .On 2 nd May one nestling and two eggs of Common Buzzard was found in the nest .During a visit to the study area I recorded an unsuccessful brood attempt of the Tree Sparrow in nest of Common Buzzard .On 2 nd May I observed one individual of the Tree Sparrow flying with an artificial thread into the Buzzard nest .After a few seconds he flew out from the lower part of the nest and headed toward buildings .When I visited the nest for the second time on 10 th May it was out of the tree and lay on the ground .I noticed two individuals of Tree Sparrows in Black Alders .The nest was probably removed by farmers persecuting birds of prey .This observation proves a high ecological adaptability of Tree Sparrow and indicates its flexibility in choosing nest-site .Also for the type of material used in nest construction .From among 1073 Tree Sparrow nest cards Seel (1964) found only two (0,19% of total cards) in nest of Common Buzzard .It shows it is definitely not a common occurrence .Nesting in nests of bigger birds ensures some benefits for Tree Sparrow .Using a foundation of large nest as a niche for its nest reduces energy expenditure for searching and carrying material for building (Indykiewicz 1998) .The nest located in nest of the other birds is durable and more resistant to weather conditions (Pinowski et al . 2006) .