During two visits to Provideniya - the administrative center of Providensky District, Chukotka Autonomous Okrug, Russia, to get clearance on the ship from the Russian authorities I observed several Eurasian tree sparrows (40 on the 17 September 2015 and 8 on the 9 September 2016, full checklist available at http://ebird.org/ebird/view/checklist/S25473286 and http://ebird.org/ebird/view/checklist/S32223163, respectively). Although I could not take any picture, I observed the birds at a very close range (few meters only) and for long minutes so I am certain about the identification.
Provideniya is located at 64°25’ N / 173°13’ W and therefore is about 1300 km northeast of the known range of the species (Brazil 2009, del Hoyo & Collar 2016 and Summers-Smith 2017). This place is rather rarely visited and birding trip reports nearly inexistent. Beside the two observations reported herein, I could not find any other record of this species that far North accept the one from Roy and Lorraine Ingleston on the 21 June 2010, also at Provideniya (number of birds unspecified, see the checklist at http://ebird.org/ebird/view/checklist/S6682432).
As the three observations mentioned here were made during the summer, I do not know if this population is present the whole year around in Provideniya or if it migrates further south during the winter. If so, maybe this population is mixing in winter with resident birds on the known range and is therefore undetected.
According to the range of the 11 different subspecies recognized in the HBW Alive for Eurasian Tree Sparrow (Passer montanus) the Provideniya’s population belongs most likely to the nominate montanus.
In the mid 1980s Flint et al. (1984:296-297) do not mention the species in Chukotka or Kamchatka. According to Summers-Smith (2009) the species ws already present in the Kamchatka Peninsula in the late 2000s. Therefore, in about 25 years Eurasian Tree Sparrows have expanded their range northeastwards. The observations mentioned here (from 2010, 2015 and 2016) show that the species continues to expand to the North.
I thank José Luis Copete who reviewed this note.
Brazil, M. (2009) Field Guide to the Birds of East Asia: Eastern China, Taiwan, Korea, Japan and Eastern Russia. Christopher Helm, London.
Flint, V.E., Boehme, R.L., Kostin, Y.V. & Kuznetzov, A.A. (1984) A Field Guide to the Birds of the USSR. Princeton University Press, Princeton, New Jersey.
del Hoyo, J. & Collar, N. J. (2016) HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions, Barcelona.
Summers-Smith, D. (2009) Eurasian Tree Sparrow (Passer montanus). In: del Hoyo, J., Elliott, A. & Christie, D.A. (eds.). Handbook of the Birds of the World. Volume 14. Lynx Edicions, Barcelona.
Summers-Smith, D. (2017) - Eurasian Tree Sparrow (Passer montanus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona (retrieved from http://www.hbw.com/node/60946 on 10 July 2017).