When
a bird is faced with a predator, its only objective is to escape. However, city
birds do not react in the same way as their countryside counterparts, despite
being from the same species. Urbanisation plays an influential role in their
survival strategies.
To study this phenomenon, Juan Diego Ibáñez-Álamo,
researcher at the University of Granada (UGR) and Anders Pape Møller from
Paris-Sud University (France) analysed the escape techniques of 1,132 birds belonging
to 15 species in different rural and urban areas.
Published in the Animal
Behaviour journal, the results show that city birds have changed their
behaviour to adapt to new threats like cats (their main predator in the city)
instead of their more traditional enemies in the countryside, such as the
sparrow hawk. "When they are captured, city birds are less aggressive,
they produce alarm calls more frequently, they remain more paralysed when
attacked by their predator and they loose more feathers than their countryside
counterparts," as explained to SINC by Juan Diego Ibáñez-Álamo. The
surprising thing is that urbanisation is directly linked with these
differences, which become more acute the earlier the former has taken place.
This suggests that escape strategies evolve alongside the expansion of cities;
a concept that is on the increase worldwide.
Read more at: http://phys.org/news/2012-11-city-birds-predators.html#jCp
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