Human related bird flushes are of little consequence to wintering waterbirds in a tropical coastal wetland in Ghana

Abstract

To a large extent the wintering period of Palearctic migrant waterbirds in coastal W Africa overlaps with the peak period of wetland resource use by humans. Several studies have identified this overlap as having a negative impact on birds in the form of direct and indirect competitions for food resources. But an aspect of the relationship between birds and humans that has not yet been studied in detail in W Africa is direct disturbance causing birds to flush (i.e. to take flight). In this study, we investigated the nature and pattern of bird flushes between 08h00 and 16h00 GMT at Sakumo II Lagoon, a coastal Ramsar site in Ghana located in a rapidly expanding urban area that makes it particularly vulnerable to human disturbance. The results show that fishing activities resulted in the largest number of bird flushes. Overall we recorded 0.6 flushes per hour and mean flight time was 61 seconds per flush; therefore on average the birds spent 36 seconds per hour in flight as a result of being flushed. Total time spent in flight as a result of being flushed constituted only 1% of the 96 hours of our observations between 08h00 and 16h00, but the impact of flushing over each 24-h day must be much smaller as few people are present in the evening or night. Although the severity of the impact on birds of being flushed depends on whether they are hard-pressed for foraging time, direct human disturbance appears to be of little consequence to waterbird foraging activities at Sakumo II Lagoon and may be of low significance generally to their conservation in West African coastal wetlands. © 2013, International Wader Study Group. All rights reserved.