Monitoring of spotted eagles in Estonia in 1994–2014: Stability of the lesser spotted eagle (Aquila pomarina) and decline of the greater spotted eagle (A. clanga)

Abstract Population trends of the lesser and greater spotted eagle in Estonia were comparatively estimated using data obtained in 1994-2014 from the monitoring scheme of common raptors and from special plots for monitoring of spotted eagles. Both approaches had pros and cons, but resulted in similar population trends. The numbers of the lesser spotted eagle have had minor fluctuations over the last two decades but the overall trend is stable; the current population size is estimated as 600-700 pairs. The number of greater spotted eagle breeding territories (pure-species and mixed pairs pooled) have significantly decreased, for example by 14% per year in 2004-2010, though in recent years the numbers seem to be stabilised at a critically low level. The decline of pure-species pairs was somewhat steeper than that ofmixed pairs, their proportion decreasing from a third to a quarter of the greater spotted eagle breeding territories. Altogether 5-10 breeding territories of the greater spotted eagle may be found nowadays in Estonia.