Endemic to U.S.A., Brown-capped Rosy Finch (Leucosticte australis) is found only in the Rocky Mountains from southern Wyoming to northern New Mexico (Clement 2018). A high-altitude, tundra breeder, it will conduct some altitudinal movements to avoid severe weather in the non-breeding season (Clement 2018). Its adaptation to these conditions do mean that it may be vulnerable to the effects of climate change (Conrad 2015), including the spread of montane forest to higher elevations, which will lead to the disappearance of the species’s favoured tundra habitat (Rosenberg et al. 2016).
Partners in Flight recently placed this species on the Red Watch List (along with Black Rosy Finch, Leucosticte atrata; see separate forum topic for this species here), as it is considered to have undergone large declines since 1970 (Rosenberg et al. 2016). The threat of climate change also means that such declines may also continue into the future. Given that the species is currently listed as Least Concern (see BirdLife International 2018), it appears likely that this species warrants a re-assessment. Therefore, we have re-assessed the species here against all criteria.
Criterion A – Partners in Flight (Rosenberg et al. 2016) have placed the decline between 1970 and 2014 at 95%. This would then equate to a decline of 51.1% over 3 generations (10.5 years), and with Partners in Flight suggesting that the key threat to this species is climate change, then this threat is likely to continue into the future. This rate of decline meets the threshold (>50%) for Endangered, and so the species could be listed as such under criteria A2ac+3c+4ac.
Criterion B – The species’s Extent of Occurrence in the breeding season is 117,000km2, and 188,000km2 in the non-breeding season. Therefore, these values far exceed the threshold (<20,000 km2) for Vulnerable under criterion B1. Its Area of Occupancy has not been calculated per IUCN guidelines (i.e. based on 2×2 km grid occupancy), but given the size of the Extent of Occurrence, it is unlikely to approach the threshold for Vulnerable under criterion B2 (2,000km2). Therefore, the species does not warrant listing under this criterion.
Criterion C – Rosenberg et al. (2016) give a population size estimate of 45,000 mature individuals. Therefore, the species would not approach the threshold population size for Vulnerable under this criterion (10,000 mature individuals). Thus, it does not warrant listing under this criterion.
Criterion D – The population size and range of this species are too large to warrant listing under criterion D.
Criterion E – To the best of our knowledge there has been no quantitative analysis of extinction risk conducted for this species. Therefore, it cannot be assessed against this criterion.
Therefore, it is proposed that Brown-capped Rosy-finch be uplisted to Endangered under criteria A2ac+3c+4ac. Comments are welcome but please note that this topic is not designed to be a general discussion about the ecology of the species, rather a discussion of the species’ Red List status. Therefore, please make sure your comments are about the proposed listing.
BirdLife International. 2018. Species factsheet: Leucosticte australis. Downloaded from http://www.birdlife.org on 11/05/2018.
Clement, P. 2018. Brown-capped Rosy-finch (Leucosticte australis). 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 https://www.hbw.com/node/61376 on 11 January 2018).
Conrad, E. C. 2015. Using species distribution models to quantify climate change impacts on the Rosy-finch superspecies: an alpine obligate. University of Utah.
Rosenberg, K. V., Kennedy, J. A., Dettmers, R., Ford, R. P., Reynolds, D., Alexander, J. D., Beardmore, C. J., Blancher, P. J., Bogart, R. E., Butcher, G. S., Camfield, A. F., Couturier, A., Demarest, D. W., Easton, W. E., Giocomo, J. J., Keller, R. H., Mini, A. E., Panjabi, A. O., Pashley, D. N., Rich, T. D., Ruth, J. M., Stabins, H., Stanton, J. and Will., T. 2016. Partners in Flight Landbird Conservation Plan: 2016 Revision for Canada and Continental United States. Partners in Flight Science Committee.