Breeding Biology and Ecology of Different European and Asiatic Populations of the Great Reed Warbler Acrocephalus arundinaceus

Abstract

A comparison between various populations of the Great Reed Warbler Acrocephalus arundinaceus was made using published and unpublished data. The comparison showed that most differences are consistent with a division into subspecies. The majority of birds from the nominate subspecies go through a complete moult in late autumn in north Africa, and then continue migration to winter quarters south of the equator. The majority of the eastern subspecies moult completely just after the breeding season. In contrast the orientalis birds spent extremely short periods on migration and long periods in the winter quarters. Orientalis also show more habitat tolerance (breeding in bushes, small trees, and no water), higher breeding density, less nestling starvation, and more Cuckoo Cuculus canorus brood-parasitism.However, some of these features may be due to the fact that some of orientalis populations live in extremely changed (man-made) habitats. On the other hand, clutch-size, total nest-losses, eggs hatchability, fledglings production, and nestling diet composition showed interpopulation variation independent of the subspecies division.

Breeding ecology of the Eastern Great Reed WarblerAcrocephalus arundinaceus orientalisat Lake Kasumigaura, central Japan

“…The breeding density of the Kasumigaura population was high compared with other populations, although it fell within typical ranges (10-25/ha) of other Japanese populations (Urano 1985, Ezaki 1990, Yamagishi et al 1994, Dyrcz 1995. Breeding statistics from our study areas across the whole breeding season are almost identical to other populations in Japan (Nibe 1915, Saitou 1976, Urano 1985, Ezaki 1990).…”

“…The Japanese race defend small compact territories in reed-bed, which provide mainly nesting sites, and they use neighbouring paddies and/or lotus fields as a foraging sites (Ezaki 1992). On the other hand, the European race defends a territory almost seven times that of populations described here, and often forage within their territories (Dyrcz 1995, Ezaki & Urano 1995. Higher productivity of reed-beds (net primary production in Lake Kasumigaura: 1894 g dry weight/m 2 per year; Nohara et al 1986) may enable the Japanese Great Reed Warblers to contract their territory size, as the Kasumigaura reed-beds support richer invertebrate fauna than Polish ones (Dyrcz & Flinks 2000).…”

“…In both our study sites the breeding density was extremely high compared with European populations (Dyrcz 1995, Ezaki & Urano 1995. The Japanese race defend small compact territories in reed-bed, which provide mainly nesting sites, and they use neighbouring paddies and/or lotus fields as a foraging sites (Ezaki 1992).…”

“…These studies revealed some ecological differences among populations, especially between two distant regions of the Eurasian Continent (Ezaki & Urano 1995, Dyrcz 1995. We studied the breeding ecology of the Great Reed Warbler around Lake Kasumigaura, central Japan in order to obtain comparable breeding data with Dyrcz (1981) from Polish sites.…”

Breeding ecology and behaviour of the Great Reed Warbler, Acrocephalus arundinaceus, in Poyrazlar Lake, Turkey

“…On the other hand, the first individuals in Japan were observed on 25-30 April and the laying period started on 19-25 May (Dyrcz and Nagata, 2002). In spite of being a European country, Poland showed more similarity with Japan in terms of first laying and hatching dates (Dyrcz, 1995;Ezaki and Urano, 1995). As soon as the birds arrived in the area of study at Poyrazlar Lake (Turkey), the breeding period started.…”