Nasty Reputation of Crows Not Entirely Justified, Nine-Country Study Finds

In literature, crows and ravens are a bad omen and are associated with witches. Most people believe they steal, eat other birds' eggs, and reduce the populations of other birds. But a new study, which has brought together over 326 interactions between corvids and their prey, demonstrates that their notoriety is not entirely merited. Corvids - the bird group that includes crows, ravens, and magpies - are the subject of several population control schemes, in both game and conservation environments. These controls are based on the belief that destroying them is good for other birds. They are also considered to be effective predators capable of reducing the populations of their prey. However, a study published online on December 15, 2015 in the journal Ibis analyzed the impact of six species of corvid on a total of 67 species of bird susceptible to being their prey, among which are game birds and passerine birds. The project, which compiled the information of 42 scientific studies and analyzed a total of 326 interactions between corvids and their prey, shows that they have a much smaller effect on other bird species than was previously thought. As Dr. Beatriz Arroyo, a co-author of the study and a researcher at the Institute of Research in Game Resources (IREC), a joint centre of the University of Castilla-La Mancha, the Castilla-La Mancha Community Council , and the CSIC (Spanish National Research Council), tells the Servicio de Información y Noticias Científicas (SINC), "In 81% of cases studied, corvids did not present a discernible impact on their potential prey.
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