Romanov M., Masterov V.

RJEE Vol. 8 (1). 2023 | DOI: 10.21685/2500-0578-2023-1-1
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Receipt date 10.10.2022 | Publication date 26.03.2023




M. S. Romanov1, V. B. Masterov2
1 Institute of Mathematical Problems of Biology RAS – Branch of the Keldysh Institute of Applied Mathematics of the Russian Academy of Sciences, Puschino, Russia
2 Lomonosov Moscow State University, Moscow, Russia
1, 2


Abstract. We developed an alternative approach to assessing raptor populations by fitting accumulation curves. This technique was applied to estimate the number of nesting territories of the Steller’s Sea Eagle Haliaeetus pelagicus in the northeast of Sakhalin Island and the lower reaches of the Amur River (Russian Far East). From 2004 to 2021, 428 nesting territories were found on NE Sakhalin and 422 nesting territories on the lower Amur. We selected four asymptotic functions of accumulation curves (negative exponential, Clench, Weibull and Hill) and tested three different measures of sampling effort. The best model was the one based on the negative exponential function with an offset from the origin (known as the von Bertalanffy equation), with the number of nests visited as the measure of effort. This model suggested the existence of 461 nesting territories on NE Sakhalin and 535 nesting territories on the Lower Amur. Taking into account an average territory occupancy of 69 %, we estimated the breeding population to be 318.2 territorial pairs on NE Sakhalin and 480.4 pairs on the Lower Amur. The total population was estimated to be 1079.8 birds (including 896.2 adults and 183.6 immatures) on NE Sakhalin and 1414.1 birds (1216.1 adults and 198.0 immatures) on the Lower Amur. Our experience suggests that fitting accumulation curves is a useful tool for estimating raptor populations in long-term studies, especially when total counts are impossible and objects are unevenly distributed.


Keywords: accumulation curves, model, nesting territories, Steller’s Sea Eagle, Haliaeetus pelagicus, Sakhalin Island, Amur River


Acknowledgements. We thank L. G. Khanina for the idea of the study, V. E. Smirnov, I. E. Sizov and A. N. Pankratov for the fruitful discussion of the manuscript.


For citation: Romanov M. S., Masterov V. B. Estimating the number of the Steller’s Sea Eagle nesting territories using accumulation curves. Russian Journal of Ecosystem Ecology. 2022;8(1). (In Russ.). Available from: