The real reason why birds migrate

Hungry, not picky, forced birds to travel thousands of miles between breeding and non-breeding areas each year, a new study confirms.

" It's not like you like eating insects, fruits, honey or candy bars or cupcakes, the problem is how to make sure there's food from day to day, " said W. Alice, the research leader. Boyle from the University of Arizona (USA), said.

In order to understand the real pressure of forcing birds to leave their homeland, Season Boyle examined 379 New World fly birds with relatives, comparing sizes, eating preferences, habitat and behavior. Their residence, whether or not they feed in the herd. This is one of the largest bird groups in the Americas.

The team built a " super-genealogical tree " that shows the exact evolutionary relationship between different species. The computer then determines whether a particular species migrates according to "family tradition" or their habitat changes to force them to fly seasonally.

Boyle and colleagues found that lack of food is a leading factor related to a species' migration behavior.

In addition to migration, another strategy used by birds to cope with an empty stomach is to feed on the flock, because the more children it is, the easier it is to find a source of food when alone.

A bird catches flies. (Photo: LiveScience)

T. An