Agricultural land-use patterns and the decline of the helmeted guineafowl Numida meleagris (Linnaeus 1766) in KwaZulu-Natal, South Africa

Land-use practices can impact on bird populations. This study set out to ex plain why the helmeted guineafowl, Numida meleagris (Linnaeus 1766; Aves: N umididae) declined in the Midlands of KwaZulu-Natal, South Africa, an agric ultural area where these birds were once abundant in savannas mixed with cu ltivation. Within the Midlands, the potential roles of land-use practices a nd pesticides were investigated. Using a grid cell approach, the distributi on of 11 land-uses was mapped for 19 farms with different levels of guineaf owl abundance. The edge distance between extensive and intensive agricultur e was significantly associated with the presence of guineafowl. The presenc e of guineafowl was associated with greater land-use diversity, showing thi s species' preference for a mosaic of land-uses. Extensive agricultural are as were used for cover and intensive ones for food, but the adjacency of th ese land-uses affected access to these resources. Larger flocks (greater th an or equal to 100 birds) were associated with pastures free of agro-chemic als, while smaller flocks (<100 birds) were associated with cereal lands wh ere chemicals were used. The use of chemicals may reduce reproductive succe ss by removing arthropods and weeds, which are critical food sources for fe male guineafowls and their keets during the breeding season. An inadequate grass cover for nesting may further reduce reproductive success. This study suggests that a combination of land-use spatial pattern and other factors, such as pesticide use, contributes to the decline in helmeted guineafowl p opulations in this intensively farmed area of South Africa. (C) 1999 Elsevi er Science B.V. All rights reserved.