The birds of Pasvik / E. I. Khlebosolov, O. A. Makarova, O. A. Khlebosolova [et al. ; English transl. Nikita Chernetsov]. - Ryazan : Golosgubernii, 2007. - 175 с. : ил., портр.

related to the habitats and structure o f m icrohabitats used fo r searching for food and foraging. Therefore, along with observations o f foraging behaviour, we analysed the habitat and m icrohabitat distribution o f the birds. Foraging behaviour was observed in typical habitats, all elem en ts of foraging activity were recorded by tape-reco rded . We noted the sequence o f foraging manoeuvres (hops, flights, looking around , hovering, hanging on the twigs, pursuit o f insects, picks). The length and direction o f hops and flights was estim ated by eye. For forest-dwelling bird species five directions o f movements were distinguished: vertically up, upwards, horizontally, downwards, horizontally down. The data c o l­ lected were plotted and an integrated pattern o f species-specific foraging behaviour was described, including the data on the array o f foraging m anoeuvres, their sequence, the ratio o f hops and flights o f different length and d ire ction , du ration o f looking for prey. One o f most specific characteristics o f foraging behaviour o f passerines is the sequence o f foraging movements (Khlebosolov 1993, Dubrovsky et al. 1995). Therefore we plotted foraging behaviour graphically and showed the fre­ quency and sequence o f their characteristic foraging m anoeuvres (see Khlebosolov 1993 for more information on plotting avian foraging behav iou r). For foraging manoeuvres we followed the term inology o f Holmes et al. (1979), Fitzpatrick (1980) and Remsen & Robinson (1990). Habitat use o f birds was determ ined by detailed descrip tion o f vegetation stru c ­ ture in breeding territories. A circular area o f 500 m2 was described. In each area one to three descriptions were made depending on the degree o f vegetation h e te ro ­ geneity. We recorded tree species, density o f the stand and underg row th , height o f trees and bushes, num ber o f strata, foliage projective cover and volum e o f crowns o f trees, projective cover and density o f herbs, presence o f openings and forest edges. When encountering a foraging bird, m icrohab itat, i.e. th e imm ediate foraging location comparable by size with the bird itself, was recorded. For forest-dwelling birds living in tree crowns th e species o f tree o r bush was recorded and the position o f the birds w ithin the crown. Vertically th e tree crown was divided into upper, m iddle, and lower parts. Horizontally, th e tru n k , inner, m iddle, and ou ter crown were distinguished, a rch ite c to n ics and form o f crow n, branch grow th direction and density, d istribu tion o f leaves o r need les were recorded. For the birds foraging on the ground we recorded the stru ctu re o f m icrorelief, size o f surface irregularities, ground surface, height and d istribu tion o f g round veg­ etation, proportion o f bare ground, stones, grass and o th e r variables th a t allow the birds to forage in a characteristic manner. 24