The breeding population of the Great Grey Shrike
Abstract: Since the 1980s, the breeding range of the Great Grey Shrike in Austria has been restricted to the northern part of Lower Austria. Since 1995, this breeding population has been fully censused to obtain base-line population levels. Every breeding locality was examined 6-8 times each season....
| Main Authors: | , , |
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| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
2003
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| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.567.7521 http://www.biollett.amu.edu.pl/biollett_41_2_10.pdf |
| Summary: | Abstract: Since the 1980s, the breeding range of the Great Grey Shrike in Austria has been restricted to the northern part of Lower Austria. Since 1995, this breeding population has been fully censused to obtain base-line population levels. Every breeding locality was examined 6-8 times each season. In 1995 at least 38 occupied territories were found and 32 breeding pairs confirmed. In 1997, after the two harshest winters in the study period, only 18 occupied territories and 9 breeding pairs were confirmed. But since 1998, the breeding population has increased again. In 2002, the population reached a maximum of 50 occupied territories with 47 confirmed breeding pairs. In 2003, 46 pairs bred. The nests were built in deciduous trees at lower elevations of the Weinviertel and in coniferous trees at higher elevations. Most nest trees are in small woodlots or in forest edges. In 19982003, the portion of successful breeding pairs ranged from 57 % in 2003 (n = 46) to 80 % in 2001 (n = 40). On average, 3.4 (SD = 1.1, n = 129) fledglings per successful brood were recorded. |
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