The Smithsonian Tropical Research Center reports that an incredible 2 million migratory raptors were counted over Panama City Nov. 2.
The center said that this was more than twice the previous record counted by individuals taking the bird census. This figure is also a record-setter in the annual tallies kept by the Audubon Society of Panama since 2004, it said.
The birds are on a thousand kilometer journey from North to South America, said the institute. Some 3 million birds in total are expected to be traveling south.
“The official count from Sunday’s massive raptor migration is 2,105,060 birds, most of them Turkey vultures and Swainson’s hawks,” said George Angehr, a Smithsonian ornithologist and authority on Panama’s bird life. “A large percentage of the world population of Swainson’s hawks probably passed through on their way from the Great Plains to Argentina.” He was quoted by the institute.
This one-day total may also be the single largest recorded in the Americas, the institute said.
Bad weather in Central America may create a bottleneck, limiting migration when it is rainy or cloudy, said Angehr. “When you get good flying conditions after several days of rain, they take advantage,” he said. “There must have been at least 100 miles of raptors. There was a river of birds passing all day.”
Raptors conserve energy during migration by riding columns of warm air that only form over land. Because the Isthmus of Panama is so narrow, birds are forced together and are easily seen. While the majority of the raptors are vultures and Swainson’s hawks, expert birders may spot some 20 species, said the institute.
“These birds migrate by day and at night they need the forests that we have around the city — the humid forests and also the mangrove forests,” Rosabel Miró, the executive director of the Audubon in Panama, told news station TVN-2. She added this reinforces the need for legislation to protect the mangroves of the Bay of Panama. She also was quoted by the institute.
The count, sponsored by Fundación Natura, is carried out from Oct. 1 to Nov. 18 on Ancon Hill, the landmark at the Pacific gateway to the Panama Canal.