Disturbance—the response of birds to a stimulus such as the presence of a person—is considered a conservation threat for some Australian birds. The distance at which a bird flees from perceived dan...
One way to manage disturbance to waterbirds in natural areas where humans require access is to promote the occurrence of stimuli for which birds tolerate closer approaches, and so cause fewer responses. We conducted 730 experimental approaches to 39 species of waterbird, using five stimulus types (single walker, three walkers, bicycle, car and bus) selected to mimic different human management options available for a controlled access, Ramsar-listed wetland. Across species, where differences existed (56% of 25 cases), motor vehicles always evoked shorter flight-initiation distances (FID) than humans on foot. The influence of stimulus type on FID varied across four species for which enough data were available for complete cross-stimulus analysis. All four varied FID in relation to stimuli, differing in 4 to 7 of 10 possible comparisons. Where differences occurred, the effect size was generally modest, suggesting that managing stimulus type (e.g. by requiring people to use vehicles) may have species-specific, modest benefits, at least for the waterbirds we studied. However, different stimulus types have different capacities to reduce the frequency of disturbance (i.e. by carrying more people) and vary in their capacity to travel around important habitat.
Background: Interactions between wildlife and humans are increasing. Urban animals are often less wary of humans than their non-urban counterparts, which could be explained by habituation, adaptation or local site selection. Under local site selection, individuals that are less tolerant of humans are less likely to settle in urban areas. However, there is little evidence for such temperament-based site selection, and even less is known about its underlying genetic basis. We tested whether site selection in urban and non-urban habitats by black swans (Cygnus atratus) was associated with polymorphisms in two genes linked to fear in animals, the dopamine receptor D4(DRD4) and serotonin transporter (SERT) genes.Results: Wariness in swans was highly repeatable between disturbance events (repeatability = 0.61) and non-urban swans initiated escape from humans earlier than urban swans. We found no inter-individual variation in the SERT gene, but identified five DRD4 genotypes and an association between DRD4 genotype and wariness. Individuals possessing the most common DRD4 genotype were less wary than individuals possessing rarer genotypes. As predicted by the local site selection hypothesis, genotypes associated with wary behaviour were over three times more frequent at the non-urban site. This resulted in moderate population differentiation at DRD4 (FST = 0.080), despite the sites being separated by only 30 km, a short distance for this highly-mobile species. Low population differentiation at neutrally-selected microsatellite loci and the likely occasional migration of swans between the populations reduces the likelihood of local site adaptations.Conclusion: Our results suggest that wariness in swans is partly genetically-determined and that wary swans settle in less-disturbed areas. More generally, our findings suggest that site-specific management strategies may be necessary that consider the temperament of local animals.
1 November 2014 in Journal of Environmental Management
We reviewed 272 bird atlases (standardised surveys intended to document the distribution of birds) from around the world. Atlases we located were conducted in 50 countries from six continents with most (82.4%) from Europe and North America. Atlases were mostly run by ornithological societies (67.1%), had amassed at least 27.9 million records of birds over an area roughly 31.4% of the land area of the Earth, and had involved at least 108 000 contributors. They had a modal data collection period of 4 years (some ran over several decades) and varied greatly in scale, covering local areas to entire continents (21 km2—10390000 km2); atlases that covered larger areas involved more observers and generated more records. Most atlases (88.3%) were constrained to particular seasons, and most of these focussed on the main local breeding period (81.0%). Spatial sampling units ranged from 0.02 km2 (2 ha) to 3092 km2, temporal units of sampling varied from 20 minutes to several years. Little information is avail...