Roadside scavengers: Researchers investigate the roadkill we never see

Roadkill scavenging

A new study published in the Journal of Urban Ecology (Oxford University Press), by lead author and KESS 2 student Amy Williams Schwartz of Cardiff University, indicates that the number of wild animals killed by motor vehicles may be much higher than is generally reported or understood.

KESS 2 project researchers, working in collaboration with Eco-explore Community Interest Company and supported by European Social Funds through the Welsh Government, used baited camera traps in twelve sites around Cardiff with the aim of identifying roadkill scavengers. Although scientists have previously studied roadkill in numerous ways, this is the first time camera traps have been used to document scavenging activity.

Wildlife deaths on British roads number in the millions every year, so the resulting carcasses represent a substantial source of food for scavengers. By removing roadkill in urban areas, scavengers perform a valuable ecosystem service, but the rapid removal of these carcasses by scavengers could be leading scientists to underestimate the impacts of roads on wildlife.

Amy Williams Schwartz said “Removal of animals by scavengers is believed to be the most important factor causing underestimations of roadkill numbers, particularly of small animals such as garden birds and rodents. Our study demonstrates the frequency and speed at which scavengers can remove roadkill, and the extent to which we could underestimate the true number of casualties, but also suggests that many urban scavengers such as crows, gulls, and foxes could be providing an under-appreciated and largely unnoticed carcass removal service in our cities.”

In order to evaluate the scale and context of urban roadkill scavenging, researchers examined which species scavenge on roadkill in urban areas, the likelihood of roadkill being removed by scavengers, and whether factors such as habitat type and time of day influenced the rate of removal.

Findings show that corvids are the most common scavengers of roadkill and the researchers observed a peak in scavenging activity shortly after sunrise, which reflects a typical peak in bird activity at this time. These results suggest there could be potentially up to six times as many incidents of wildlife roadkill as current estimates show.

To find out more and read the paper in full, visit:
Roadkill scavenging behaviour in an urban environment, Journal of Urban Ecology (2018)

This study was also covered by the following online media websites: (14 May 2018):

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