First Records of the Firecrest (Regulus ignicapilla, Regulidae, Aves) from the Northern Slopes of the Western 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 listed in the Red Data Book of Krasnodar krai. Research was carried out from 2006 to 2023 in the Western Caucasus. The length of the surveyed routes totaled 8885 km. The population census was conducted over 2096 km of the routes. Since 2022, field detection of the species has become significantly improved through the use of conspecific playback. As a result, new breeding grounds have been detected on the northern macroslope in the vicinity of the Guzeripl ranger station in the Caucasus Nature Reserve, in the Malaya Laba River valley, and in the Bolshoi Tkhach Nature Park, while the distribution in the Mzymta River valley has also been clarified. New overwintering grounds in the piedmont zone of the Black Sea region and on the pre-Kuban Plain are shown. These data have significantly expanded the known range of the firecrest in the Western 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 macroslope of the Main Caucasian Range, firecrests co-occur with goldcrests across elevations of 880–1580 m above sea level; while on the southern macroslope, at 840–1680 m asl. At higher altitudes, only goldcrests are found. The new data on the distribution and population density make it possible to provide estimates of the current abundance of the populations in Krasnodar krai (3900 pairs), the Adygean Republic (1800 pairs), and Abkhazia (2100 pairs), and in the entire Western Caucasus (7800 pairs).