Tolerance of Human Disturbance by Urban Magpie-larks

Abstract

To successfully colonise cities, birds must be highly tolerant of human traffic. We examined this tolerance in a native urban coloniser, the Magpie-lark Grallina cyanoleuca, in suburban Melbourne, Victoria. We compared flushing behaviour and the Flight Initiation Distance (FID) of urban and rural individuals, and of urban individuals encountered near to and farther away from roads and pathways carrying vehicular and pedestrian traffic. Mean FID to a researcher was 12 ± 1 m in Melbourne, compared with 35 ± 3 m in rural Victoria. Rural birds also flushed more by flying (100% versus 57.6%) and fled farther than urban individuals. Mean FID to a researcher was 1.9 times larger farther from (13 ± 2 m) than near to (7 ± 0.6 m) urban roads, but time allocations to vigilance (24.1%) and foraging (65.5–69.4%) and the percentage of birds that flushed (86% and 75%) were similar in the two locations. People caused more of the flushing of Magpie-larks near to (55%) than farther from (20%) urban roads and pedestrian pathways. We speculate that the disparities in flushing behaviour (urban/rural and near to/farther from urban roads) probably resulted mainly from habituation, a learning process that could be critical in facilitating urban colonisation and use of habitat near busy urban traffic corridors by members of temperamentally inherently ‘bold’ species.