Anthropogenic impacts on the composition and population density of migratory and resident birds of selected wetlands sectors in northern Nigeria

Abstract

In recent times, there has been decrease in the number of migratory and resident birds in Hadejia-Nguru Wetlands in Nigeria. This, no doubt, is a subject of concern to conservationist and the country at large. The effect of anthropogenic activities on the composition and population density of migratory and resident birds in Hadejia-Nguru Wetlands, Nigeria, were undertaken for a period of two months. Point-count method was used in data collection in two sectors of the wetlands: Ox-Bow Lake and Marma Channel. Visual observation and interaction with the locals around the wetlands were used to assess the level of anthropogenic influences and scored on a scale of 0-5. Forty-five species of migratory and resident birds were recorded of which 25 were resident while 14 and 6 were migratory and Afro-migrant respectively. A total of 32,442 and 2,218 individual birds were recorded in Ox-Bow Lake and Marma Channel respectively. Garganey (Anas querquedula) was the highest recorded species during the survey and it was preponderant in Ox-Bow Lake. Garganey was also more densely populated (903.76 birds/hectares). Canonical correspondence analysis showed that washing/bathing and open defecation negatively affected the composition of Anas querquedula and Anas acuta. The study revealed Hadejia-Nguru Wetlands to be under threat. Therefore, appropriate enforcement of laws guiding migratory birds in Nigeria is hereby recommended.

Keywords: Anthropogenic activities; bird population density; migratory birds; Garganey (Anas querquedula); Hadejia-Nguru Wetlands; Nigeria