Thursday 4 October 2012

Sudan, Sahel zone, Blue Nile, Gezira cultivations - By Peter Dare

Sudan, Sahel zone, Blue Nile, Gezira cultivations, 14º 30’N Annual rainfall  200-400 mm

Irrigation canal and Acacia nilotica trees, Wad Medani

Fields and canal – a typical Gezira landscape

A vast area (860,000 ha, 8,600 km²) of the arid clay plain on the Gezira, between the Blue and White Niles, has been converted since 1925 into cereal and cotton production using gravity-flow irrigation canals from a dam on the Blue Nile at Sennar.  The virtually tree-less Gezira landscape supports large populations of Palaearctic migrants on passage and in winter. Several thousand Demoiselle Crane, with a few European Crane, forage harvested grain fields as do thousands of Ruff. Irrigated fields and rain floods attract large Pratincole flocks and many waders – especially Wood, Green and Common Sandpipers, and Little Ringed Plover. European Swallow and Swift, and flocks of Yellow Wagtail variants are regular in autumn. Pallid and Marsh Harriers were widespread. Less frequent species include: Purple Heron, Squacco Heron, White Stork (autumn), Glossy Ibis (autumn & spring), Garganey (autumn), Short-toed Eagle (autumn & winter), Common Kestrel, Lesser Kestrel (autumn), White-winged Black Tern (both passages), Ringed Plover and Black-winged Stilt, Little & Temminck’s Stints (autumn & spring), Blue-cheeked Bee-eater (autumn), Sand Martin, Northern Wheatear, and White Wagtail.  Rarer species: Bittern, Little Bittern, Mallard, Griffon Vulture (north end), Steppe Eagle (spring, N end), Booted Eagle (winter), Montagu’s Harrier (spring), Peregrine (autumn), Osprey (spring), Hobby, Saker Falcon (winter, N end), Honey-Buzzard (spring), European Quail, Caspian Plover, Common Snipe, Black-tailed Godwit (autumn), Greenshank (autumn), Marsh Sandpiper (autumn), Gull-billed Tern and House Martin (autumn).

African inter-tropical migrants:  Numerous Cattle Egret, Sacred Ibis, Abdim’s Stork, and some Black-headed Heron, fed in the fields when breeding in scattered colonies in village trees during the summer rains. Carmine Bee-eaters from colonies along the Blue Nile river banks foraged daily over the fields. All these returned south in late autumn.

Amid the extensive Gezira cultivations, the large area of garden shrubberies, mature trees and lawns at the Wad Medani research station provided a veritable ‘oasis’ of cover and feeding habitats for many Palaearctic passerines as well as resident African species and inter-tropical migrants extending north during the rains. Palaearctic species wintering here were:  Turtle Dove, White Wagtail, Masked Shrike, Black-eared Wheatear, Common Redstart, Lesser Whitethroat, Olivaceous Warbler, and Chiffchaff. Regularly passing through in small numbers in autumn were Spotted Flycatcher and Thrush-Nightingale.  Less regular were: Hoopoe, Rock Thrush, Willow Warbler and Red-backed Shrike. There were single records of: Eurasian Sparrowhawk, Eurasian Cuckoo, Grey Wagtail, Rufous Bush Chat, Blue Rock Thrush, Collared/Semi-collared Flycatcher, Common Whitethroat, Garden Warbler, Golden Oriole and Cretzschmar’s Bunting. Pallid Harrier occasionally hunted through the more open gardens.

Most of these species visited my garden (illustrated) as did some waders when the lawn was flooded: Little Ringed Plover, Green Sandpiper and Wood Sandpiper (7 together in August). Many of the other Palaearctic species (listed earlier) passed over on passage or when feeding in the fields.

Resident African species at the research station, and noted elsewhere in Gezira, comprised:  Black Kite (abundant), Shikra (small Accipiter), White-browed Coucal, Pied Kingfisher, Blue-naped Mousebird, Palm Swift, White-faced Scops Owl, Grey-cheeked Woodpecker, Black-billed Wood Dove, Long-tailed Dove, Chestnut Finch-lark, White-headed Babbler, White-vented Bulbul, Black Bush Robin, three warblers, Common Drongo, Black & Red Shrike, Pied Crow, Beautiful Sunbird, House Sparrow, Grey Sparrow, Red-billed Quelea,  and 6 other weavers. Tawny Eagles and non-breeding vultures were ever-present in the sky, scanning for dead livestock - mainly Hooded, Rűppell’s Griffon and Lappet-faced with an occasional Egyptian, White-backed and White-headed Vulture. Exceptionally, a Secretary Bird was seen in the southern Gezira.

The residents were augmented during the rains by migrants from the south, some to breed but others being casual visitors. In addition to those already mentioned, these migrants to the Gezira comprised: Grey Pelican, Reed Cormorant, Darter, Green-backed Heron, Night Heron, Great White and Yellow-billed Egrets, Wood Ibis, Marabou, Woolly-necked Stork, Open-bill Stork, Gabar Goshawk, Chanting Goshawk, Red-necked Buzzard, Bateleur Eagle. Long-Crested Eagle, Harrier-Hawk, Harlequin Quail, Senegal Stone-Curlew, Blackhead, Wattled & Kittlitz’s Plovers, Pied Cuckoo, Senegal Kingfisher, Little Bee-eater, Grey Hornbill, Yellow-fronted Tinker-Bird, White-bellied Barbet, Ethiopian Swallow, Paradise Flycatcher, Abyssinian Roller, Zitting Cisticola, Green-tailed Starling, Cape Rook, Little Weaver and White-rumped Seed-eater. Most of the African species also visited or passed over the above garden.

P.J.Dare  2010

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