Bluethroat (Luscinia svecica) in Sumy region

Bluethroat (Luscinia svecica) in Sumy region. - M.P. Knysh. - Berkut. 34 (1). 2025. - We have summarized long-term data (1969–2024) on the distribution, abundance, and ecology of the species in the region (NE Ukraine). Several color forms of Bluethroat are occurred here: 50.0% of individuals were white-spotted, 48.3% were red-spotted, and 1.7% had a completely blue plastron. In typical habitats, the population density was 20.0–69.8 pairs/km2, sometimes reached 103.4 pairs/km2. Number of the species is relatively stable, its fluctuations are mainly associated with successional changes in biotopes and various anthropogenic influences. In spring, Bluethroats arrived in Sumy region from March 31 (1983) to April 25 (1997), most often in the first half of April. They sing from the time of arrival until the beginning of July. The song is imitative, and the singing repertoire is rich. The earliest clutch was started on April 18 (2015), the latest one – on June 21 (1986). Most (82.8%) pairs began nesting in April and May, with the peak of egg laying (27.1%) in the first decade of May. Repeated clutches were observed in June (17.2%), the question of normal second clutches remains controversial. Nests (n = 71) were located mainly in natural habitats, occasionally also in abandoned village yards and vegetable gardens. The full clutches (n = 56) had from 4 to 8 eggs, on average 5.57 ± 0.08 eggs. Measurements of eggs (n = 137; 29 clutches), mm: 16.8–21.1 × 13.1–15.5, on average 18.60 ± 0.07 × 14.28 ± 0.04. In 33 nests, 168 (91.3%) of 184 eggs hatched and 148 (80.4%) chicks fledged, an average of 4.48±0.23 chicks per nest. Departure began in the second half of August, the last records in the Sumy district were on September 1 (2020) – September 24 (2022), on average 10.09 ± 2.4 days (n = 9). [Ukrainian].