To the reproduction biology of the Wryneck (Jynx torquilla Linnaeus, 1758) in artificial nests in Northeastern Ukraine

In many countries, the Jynx torquilla population has declined significantly. In Ukraine, the species is considered widespread, but remains poorly studied. Activities to attract birds to parks using artificial nests were carried out during 2004‒2021 in Northeastern Ukraine. The first time the J. torquilla was populated in artificial nests dates back to 2009. During 2019‒2021 4 cases of J. torquilla nesting in artificial nests were recorded. Among the studied territories, the population of J. torquilla in artificial nests was found in the territory of the regional landscape park (RLP) «Feldman Ecopark», NPP «Gomilshansky forests» near the village. Gaidary in Kharkov and the tract «Vakalovschina» near the village Vakalovschina in Sumy regions. In the Northeastern of Ukraine, the number of J. torquilla reaches 14,3±0,32 pairs/km2 in the oak forests of the NPP «Gomilshansky forests» near the village Gaidary, 7,2±0,14 pairs/km2 in the pine forests of the park near the village Zadonetske, 16,2±0,14 pairs/km2 in the «Vakalovschina» tract, 11,1±0,24 pairs/km2 in RLP «Feldman Ecopark». J. torquilla, as a typical hollow-hole, is able to inhabit artificial nests. On average, during 2004–2021, the arrival of the first individuals in the spring was recorded: 21.04 at an average daily temperature of 18° C in the oak grove of the NPP «Gomilshansky forests», 23.04 at a temperature of 17° C in the tract «Vakalovschina», on the territory RLP «Feldman Ecopark» ‒ 02.05 at a temperature of 17° C, 2020 is 05.05 at a temperature of 20° С. It has been proven that 12 days pass from the moment of arrival of birds to the laying of the first egg. The first eggs of birds in the conditions of Northeastern Ukraine, on average, for all years of research, were registered 02.05 in the oak grove of the NPP «Gomilshansky forestsп», 04.05 in the tract «Vakalovschina». On the territory of RLP «Feldman Ecopark» in 2019, the first egg was laid at 14.05 on the material of the nest of the collared flycatcher Ficedula albicollis (Temm., 1815); in 2020 ‒ 19.05. Average clutch size 8,3±0,5 (from 7 to 9). Egg sizes: length – 20,2±0,2 mm, width ‒ 15,1±0,1 mm, volume ‒ 1.4±0.1 mmᶾ, roundness index ‒ 74.7±0.3 %. On average, incubation lasts 13±0,2 days. On the territory of the NPP «Gomilshansky forests» near the village. Gaidary, chicks hatched at 14.05; in the tract «Vakalovschina» on 16.05, on the territory of the RLP «Feldman Ecopark» in 2019 the chicks hatched on 26.05, in 2020 ‒ 01.06. The hatching success was found to be 96,9 % (n=30), where the breeding success is 91,0 %.