Meyburg, B.-U. & R. D. Chancellor eds. 1996
Eagle Studies
World Working Group on Birds of Prey (WWGBP)
Berlin, London & Paris


Der Schreiadler Aquila pomarina:
Bestandssituation und derzeitiger Stand
seiner Erforschung

The Lesser Spotted Eagle Aquila pomarina:
Population Status and
Present State of Research

Bernd-U. Meyburg

ZUSAMMENFASSUNG

Der derzeitige Stand der Schreiadlerforschung wird analysiert und mit der Situation vor fünf Jahren (Meyburg 1991) verglichen. Neue Untersuchungstechniken (Bodentelemetrie, Satellitentelemetrie, fernsteuerbare Videotechnik, DNA-Sequenzierung) haben die Forschung rasch vorangetrieben, viele Ergebnisse sind jedoch noch nicht publiziert. Intensiviert wurden auch die Zählungen durchziehender Schreiadler im Herbst in Israel und an anderen Konzentrationspunkten sowie Bestandserfassungen in den Brutgebieten.

Herbstzählungen in Israel (1982-87 durchschnittlich 104.000 Individuen pro Saison, 1988-95 durchschnittlich 75.000 pro Saison) sprechen für einen Rückgang des Gesamtbestandes um über 25 % innerhalb der letzten zwei Jahrzehnte. Wie im Einzelnen dargelegt wird, können vorsichtige Hochrechnungen von Teilbeständen durchaus die Durchzugszahlen in Israel erklären.



SUMMARY

The current knowledge of the Lesser Spotted Eagle is analysed and compared with the situation five years ago (Meyburg l991). New research techniques (ground telemetry, satellite telemetry, remote control video, DNA sequencing) have rapidly advanced our knowledge of the species, but many results of recent investigations are still unpublished. Lesser Spotted Eagle counts in autumn in Israel and at other concentration points during migration have been intensified and similarly censuses taken in the breeding territories.

Autumn counts in Israel (1982-87 an average 104,000 Lesser Spotted Eagles on passage per season, 1988-95 an average 75,000 per season) indicate a decline in the overall population of over 25% within the last two decades. This is the first case where a species described in the literature as scarce and even endangered has turned out to have a rather important world population. No count of a bird species from a migration survey ever aroused such fierce resistance from some established specialists in the breeding areas. It is therefore attempted here to correlate these migration figures to populations in all the countries where the species breeds. As is shown country by country, careful projections of population density figures from areas or countries well censused to the whole area of distribution can explain the numbers counted in Israel. In many cases one can roughly estimate the overall density for large areas or countries to be ca. 1 breeding pair per 100 km² (e.g. in Slovakia and Belarus respectively the densities for the whole country are about 1.7 breeding pairs per 100 km²). The estimated total number of pairs is given for all countries in the light of the latest assessments of numbers and density in well researched areas. A total population of 20,000 pairs is presumed which attempt annually to breed and raise 14,000 young. The remaining 21,000 eagles are probably immatures, subadults and adult non-breeders. In addition there are probably around 4,000 first-year birds which spend the breeding season following their birth in Africa.