1 research outputs found
Rural-Urban Differences in Escape Behavior of European Birds across a Latitudinal Gradient
Behavioral adjustment is a key factor that facilitates species’ coexistence with humans in
a rapidly urbanizing world. Because urban animals often experience reduced predation
risk compared to their rural counterparts, and because escape behavior is energetically
costly, we expect that urban environments will select for increased tolerance to humans.
Many studies have supported this expectation by demonstrating that urban birds have
reduced flight initiation distance (FID = predator-prey distance when escape by the
prey begins) than rural birds. Here, we advanced this approach and, for the first
time, assessed how 32 species of birds, found in 92 paired urban-rural populations,
along a 3,900 km latitudinal gradient across Europe, changed their predation risk
assessment and escape strategy as a function of living in urban areas. We found
that urban birds took longer than rural birds to be alerted to human approaches,
and urban birds tolerated closer human approach than rural birds. While both rural
and urban populations took longer to become aware of an approaching human as
latitude increased, this behavioral change with latitude is more intense in urban birds
(for a given unit of latitude, urban birds increased their pre-detection distance more
than rural birds). We also found that as mean alert distance was shorter, urban birds
escaped more quickly from approaching humans, but there was no such a relationship
in rural populations. Although, both rural and urban populations tended to escape
more quickly as latitude increased, urban birds delayed their escape more at low
latitudes when compared with rural birds. These results suggest that urban birds in
Europe live under lower predation risk than their rural counterparts. Furthermore, the patterns found in our study indicate that birds prioritize the reduction of on-going
monitoring costs when predation risk is low. We conclude that splitting escape variables
into constituent components may provide additional and complementary information on
the underlying causes of escape. This new approach is essential for understanding,
predicting, and managing wildlife in a rapidly urbanizing world.Peer reviewe