Bonte Kraaien Corvus cornix in Noordenveld. Hoe lang nog?
Drentse vogels , Volume 21 - Issue 1 p. 74- 77
Monthly counts of Hooded Crows in North-Western Drenthe since 1989 overall showed low numbers dwindling to 5 or less since 2005 (Table 1). This decline is consistent with the long-term trend in the province of Drenthe, where an estimated 4500-4800 in 1978-83 declined to 300 in 1990. This decrease has persisted to the present day. In the study area Hooded Crows show a tendency to winter at particular patches and rarely occur in more that one location in any one winter (Table 1). The reason for this sedentary' behaviour, interrupted by sudden shifts, is not known. The decrease of the crows, which probably originate from Scandinavia, might be due to improved wintering conditions closer to the breeding grounds. However, breeding numbers in Sweden have decreased almost two-fold during the past 30 years.
|552211.jpg Cover Image , 12kb|