| Titre : | Breeding population developments of gulls (Laridae) at the German North Sea coast in the second half of the 20th century |
| Auteurs : | Stefan Garthe, Auteur ; Bernd-Olaf Flore, Auteur ; Bernd Haelterlein, Auteur ; Ommo Hueppop, Auteur ; Ulrike Kubetzki, Auteur ; Peter Suedbeck, Auteur |
| Type de document : | Article |
| Dans : | Vogelwelt (Die) (121(1) 2000) |
| Article en page(s) : | 1-13 |
| Résumé : | Based on published literature and unpublished data for the second half of the 20th century, the population development of all gull species breeding at the German North Sea coast is described and analysed. Breeding populations of all gull species have increased considerably. Herring Gull has reached its pre-World War II population level in the early 1980s. In the other species, the formerly small populations increased strongly: Black-headed Gulls since the 1960s/70s, Kittiwakes since the 1970s/80s and Lesser Black-backed Gulls and Common Gulls since the 1980s/90s. Mediterranean Gulls (since 1982) and Great Black-backed Gulls (since 1985) have established themselves as new, regular breeding species. Little Gulls have bred only irregularly since 1965. Due to variability in strength and time of the increases, shifts in the relative numerical composition of the breeding populations have become apparent. This is most obvious for Lesser Black-backed Gulls and Herring Gulls. Thus, Lesser Black-backed have become more numerous than Herring Gulls in an increasing number of colonies although there are clear differences between colonies. A population model demonstrates that the German North Sea population of Lesser Black-backed Gulls could only increase as strongly as it did by considerable immigration from abroad (e.g. from The Netherlands). |



