Results of Bird of Prey Monitoring 2015

Report of bird of prey monitoring data 2015 revealed some expected and some unexpected trends. Among other species more attention was paid to our birds of the year - buzzards.

This year abundance and distribution of breeding raptors was surveyed in 15 monitoring sites with total area of 1305 sq km and wintering birds abundance in 22 sites with total area of 1275 sq km. All together 701 potential nesting locations were checked during the monitoring of breeding success.

During the monitoring of wintering birds 6 species were registered, in addition to that, abundance of Great Grey Shrike, who has similar ecology, was also registered. The most numerous and uniformly distributed species were Common Buzzard and Great Grey Shrike, followed by Rough-legged Hawk, Hen Harrier and White-tailed Eagle, who were distributed mostly in West-Estonia.

Pygmy Owl / Photo: Remo Savisaar

The relative abundance of Pygmy Owl from 1994 to 2014

During the breeding surveys more than 500 nesting territories of 18 raptor species were registered, while outside the monitoring areas nesting of Eagle Owl, Red Kite, Greater Spotted Eagle and Merlin were also registered this year. The largest abundance decline during the last decade concerns Hen Harrier, who is by now almost extinct as a breeding species in Estonia. The abundance of Goshawk, Ural Owl and Tawny Owl has decreased almost 50% during the latest years, albeit being stabilised by now. In the beginning of the 20th century the number of Pygmy Owl was increasing for a certain period, but during the last 10 years it has been decreasing. The number of Common Buzzard, Lesser Spotted Eagle, Montagu’s Harrier and Hobby has been continually changeless. The abundance of Long-Eared Owl has fluctuated heavily, but it has stabilised by now or even exceeding the average value this year. Honey Buzzard and Tengmalm’s Owl  have been recovered from the small decline of the latest years. The biggest increase during the latest decades has been in the abundance of Marsh Harrier, but the growth has stopped recently.

The relative abundance of Lesser spotted eagle from 1994 to 2014

The relative abundance of Ural Owl from 1994 to 2014

223 nests of the checked potential ones occurred to be populated by birds. Surprisingly many Honey Buzzards started their nesting in this year’s cold early summer, but the breeding success was not exceeding the average value. Productivity of Sparrow Hawk and Marsh Harrier was about average, while Goshawk was more successful than usual.

Buzzard, Common Kestrel and Long-eared Owl, who all are feeding mainly on small rodents, have been on average level this year.


Source:  Estonian Ornithological Society