A preliminary assessment of some factors influencing the density and distribution of palearctic passerine migrants wintering in the Sahel zone of West Africa

P. Jones, J. Vickery, S. Holt, W. Cresswell*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

59 Citations (Scopus)

Abstract

Population densities of Palearctic migrant and African birds were estimated from 444 point counts, that estimated minimum density, at 10 sites in the Sahel zone of northern Nigeria during December–January 1993/94. In total, 15 Palearctic species were recorded during point counts averaging 5 species per site, and 76 African species averaging 24 species per site. The densities of Palearctic migrants varied from 1 bird ha-1 in semi-desert and highly degraded woodland, up to 8 birds ha-1 in dense Sahelian woodland. Common Whitethroats Sylvia communis were most abundant (up to 0.7 birds ha-1) in sites rich in Piliostigma reticulata trees; Subalpine Warblers S. cantillans were most abundant (up to 5.9 birds ha-1) in sites rich in Acacia spp. and Cassia sieberiana; Lesser Whitethroats S. curruca and Redstarts Phoenicurus phoenicurus were associated with high overall tree densities (both up to 0.6 birds ha-1); Northern Wheatears Oenanthe oenanthe occurred at densities of about 1 bird ha-1 at very low tree density falling to about 0.25 birds ha-1 over a wide range of intermediate tree densities. Farmland supported densities of Palearctic migrants up to 6 birds ha-1 where large trees or hedgerows remained. The densities of Palearctic Sylviidae were positively correlated with the combined densities of all ecologically similar African species of small insectivorous and/or frugivorous passerines: Palearctic warblers were half as common as their African counterparts.

Original languageEnglish
Pages (from-to)73-84
Number of pages12
JournalBird Study
Volume43
Issue number1
DOIs
Publication statusPublished - 1 Mar 1996

Keywords

  • Acacia
  • Cassia
  • Oenanthe
  • Phoenicurus
  • Piliostigma
  • Sylvia
  • Ziziphus

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