500 million birds are staying put in parts of Israel that used to serve as a pit stop along their migration route south. Frequent droughts and desertification in Africa have made food scarcer for the birds.
"In the last few decades Israel has become more than just a short stopover because many more birds and a greater number of species can no longer cross the desert," Shay Agmon, an avian coordinator for the Hula Wetland Park in Israel, told Reuters.
Since the 1950s the number of cranes—one of the most abundant species to pass through the Hula wetlands—staying put until the end of winter has risen from 1,000 to 45,000.
"It's harder for the birds to cross a much larger desert and they just cannot do it. There is not enough fuel, there are not enough 'gas stations' on the way, so Israel has [become] their biggest 'gas station,' their biggest restaurant," Agmon told Reuters.
The influx of birds is pressuring farmers as well. Migratory birds are fanning out into the fields and consuming farmers' crops. Experts caution that changes in migratory patterns could alter global food cycles as birds eat insects and protect crops. Workers at the reserve have attempted to lure the birds into the wetlands with feeding sites.
As the climate warms, environmental pressures will push more birds' wintering grounds north.
"They will stay here for longer and eventually the whole pattern of migration will change," Agmon said.