First records of the firecrest (Regulus ignicapilla, Regulidae, Aves) from the northern slopes of the West Caucasus

This paper presents the results of a study of the distribution and abundance of the Firecrest (Regulus ignicapilla), a rare bird at the edge of its distribution range and listed in the Red Data Book of the Krasnodar Territory. Research was conducted from 2006 to 2023 in the West Caucasus. The total length of the expedition routes amounted to 8,885 km. Population counts were carried out over 2096 km of the routes. Since 2022, field detection of the species has become significantly improved through the use of audio playback recordings of the species. As a result, new breeding areas have been discovered on the northern macro slope in the vicinity of the Guzeripl ranger station in the Caucasian Strict Nature Reserve, in the Malaya Laba River valley, and in the Bolshoy Thach Nature Park, while the distribution in the Mzymta River valley has also been clarified. New wintering areas in the foothills of the Black Sea region and on the Kuban Plain are shown. These data have significantly expanded the known range of the Firecrest in the West Caucasus. New information has been obtained on the altitudinal distribution of the Firecrest, as well as its relationship with the Goldcrest (Regulus regulus). On the northern macro slope of the Main Caucasus Range, firecrests live alongside goldcrests across an altitudinal range of 880–1580 m above sea-level, while on the southern macro slope they coexist across a range of 840–1680 m above sea-level. At higher altitudes, only goldcrests occur. The new data on the distribution and population density make it possible to provide estimates of the current sizes of the populations in the Krasnodar Territory (3.9 thousand pairs), the Republic of Adygea (1.8 thousand pairs), Abkhazia (2.1 thousand pairs) and in the entire West Caucasus (7.8 thousand pairs).