Materials on breeding ecology of the Marsh Warbler in forest-steppe part of Sumy region. - N.P. Knysh. - Berkut. 8 (1). 1999. P. 57-70.
Research was carried out in Sumy district of Sumy region (51 N, 34 E) in 1970-1998. Information about 158 nests was obtained. Majority of them was placed in stations with prevalence of nettle, small reed and shrub willows and was built in these plants. Spring arrival and singing begin on average 11.05 (30.04-18.05, n = 7). Last singing was registered on average 10.07 (n = 8). In songs more than 50 signals of 42 bird species of native fauna were found (Table 1). Separate males imitate signals of 1-19 bird species, on average 9,2 + 0,6. The earliest begun clutches were observed on average 25.05 (n = 8), the latest ones - 26.06 (n = 7). Peak of egg laying is in the first pentade of June (Fig. 1). Average duration of phases of reproductive cycle (days): nest building (n = 3) - 2,7 + 0,3; pause before the beginning of egg laying (n = 23) - 1,7 + 0,2; egg laying (n = 107) - 4,44 + 0,07; brooding (n = 13) - 11,8 + 0,2; feeding of nestlings (n = 10) - 10,2 + 0,2; brood rearing (n = 6) - 8,7 + 0,6. Reproductive period of the local population lasts approximately 2,5-2,7 months. By nest building on herbaceous plants number of supporting stalks is on average 5,4 + 0,2, including: dry ones - 2,9 + 0,2; fresh ones - 2,5 + 0,2. Nests are placed at height 10-90 cm (Fig. 3), on average 34,4 + 1,4 cm. For building of each nest from 1 to 9 kinds of material are used (mainly vegetable), on average 3,7 + 0,2 (n = 68). Measures of nests, clutches and eggs are given in Tables 2-4. Full clutches contain 1-5, on average 4,44 + 0,07 eggs (n = 107). Average clutch size in the first half of breeding season is 4,56 + 0,07 (n = 71), in the second one - 3,83 + 0,20 (n = 18). Broods have on average 3,78 + 0,16 hatchlings (n = 55) and 3,86 + 0,16 fledglings (n = 49). Hatching productivity (Table 5) is on average 2,06 + 0,21 (n = 101), fledging productivity - 1,87 + 0,21 youngs per active nest. These parameters essentially decrease at repeated breeding. General breeding success as a whole has made 48,3 % (Table 6). Activity of raptors and the Cuckoo is main factor of offspring death: 36,3 % losses from initial egg number or 70,3 % from general number of losses. From 29 Cuckoo's eggs in nests of the warbler 11 (37,9 %) chicks were hatched and 8 (27,6 %) ones were raised. [Russian].
Key words: Marsh Warbler, Acrocephalus palustris, Sumy region, ecology, breeding, migration, nest, clutch, breeding success, parasitism.
Address: Dr. N.P. Knysh, Sumy Pedagogical Institute, Romenskaya str. 87, 244002 Sumy, Ukraine.