ARRIVAL DATES OF THE GARDEN WARBLER SYLVIA BORIN IN CENTRAL NIGERIA

Abstract

These observations were made at Vom (9° 50′ N., 8° 50′ E.), which lies on the central plateau of Nigeria at an altitude of about 4,000 feet, in the Guinea Savannah vegetational zone. The small residential area of Vom is round the periphery of the cone of an extinct volcano. The gardens have varying numbers of tall trees (mainly eucalyptus species) and ornamental shrubs. In the immediate vicinity is open grassland, with small forestry reserves and deep water‐courses filled with varying amounts of dense bushy vegetation.

The stopover behaviour of the Garden Warbler Sylvia borin in Obudu, southeast Nigeria

“…Furthermore, Garden Warblers were first captured relatively earlier at our study site (11 October) compared to dates reported by previous studies in forested areas of Nigeria (18 November at Imesi-ile (7°33´N 4°33´E; Ludlow 1966) and 15 October at Ibadan (7°23'47''N 3°55´0''E; Parker 1968). This difference in arrival dates support the suggestion of Smith (1963) that after crossing the Sahara, Garden Warblers move southwards slowly while feeding on the way. The median passage date at Obudu is about 30 days after the reported date for birds passing through the Guinea savanna region of Nigeria (Ottosson et al 2005).…”

Garden WarblerSylvia borinmigration in sub‐Saharan West Africa

“…They concluded that Garden Warblers stop over in both the Sahel and Guinea-savannah regions of West Africa during autumn but only in the latter in spring, and that neither of these regions regularly hosts wintering birds. A further comment by Smith (2007) indicates that the data of Ottosson et al (2005) largely agree with those he had collected himself some 40 years earlier (Smith 1963(Smith , 1965(Smith , 1966 The earliest capture at Djoudj was on 13 October, over a month later than recorded by Smith (2007) or Ottosson et al (2005), whilst the latest, on 20 November, was over three weeks earlier (Table 1; see Fig 1 for study site locations). The later autumn arrival at Djoudj is most likely an artefact of capture effort, as little or no effort took place in September, whilst the earlier departure is probably a reflection of the more northerly location of Djoudj relative to the other sites (see Fig 1).…”

Garden Warbler Sylvia borin migration in sub‐Saharan West Africa: a comment on Ottosson et al. (2005)

“…Indeed, Garden Warblers were mist‐netted at Vom (9°42′N, 8°45′E), only 50 km from the Amurum study site (9°53′N, 8°59′E) of Ottosson et al . (2005), from 1960 to 1965 (Smith 1963, 1965, 1966). Their times of arrival and, during 1964 and 1965, their mean weights form an interesting comparison with data from 2001 to 2004 (Table 1), especially in the light of recent work on the phenology of long‐distance migrants (Jonzen et al .…”