The strange reason migrating birds are flocking to cities

[Michie]

Some species of migrating birds are increasingly attracted to life in the big city – but these unnatural environments can be deadly.



Ana Morales stepped through the shrubbery, scanning the airwaves with a radio receiver. The device had picked up a signal from a transmitter that she and colleagues had previously attached to a Swainson's thrush, a small brown and white speckled bird native to the Americas. The same signal had popped up on Morales' handheld receiver a few days earlier, emanating from exactly the same bush in a park on the edge of Montreal in Canada.

This was a worry. It seemed so unlikely that the transmitter remained attached to a live bird – more likely, it had fallen off and was hanging on a branch. Just to make sure, Morales, a graduate student at McGill University, gave the berry-laden shrub a gentle shake – and then a flutter of feathers among the branches and shadows caught her eye. To her surprise, the thrush, very much alive and healthy, was hopping about the bush in protest at having been disturbed. This little bird had hung around for longer than she expected.

Swainson's thrushes migrate from northern areas to Central and northern South America every autumn. But some make a "pit stop" in and around cities such as Montreal. For a study published last month, Morales and her colleagues had been researching how Swainson's thrushes balance the need to migrate quickly – so as to maximise its benefits – with the need to refuel, such as by stopping over in places like Montreal. They caught and radio tagged a total of nearly 80 of the birds.

Continued below.
The strange reason migrating birds are flocking to cities

 

[chevyontheriver]

Some species of migrating birds are increasingly attracted to life in the big city – but these unnatural environments can be deadly.



Ana Morales stepped through the shrubbery, scanning the airwaves with a radio receiver. The device had picked up a signal from a transmitter that she and colleagues had previously attached to a Swainson's thrush, a small brown and white speckled bird native to the Americas. The same signal had popped up on Morales' handheld receiver a few days earlier, emanating from exactly the same bush in a park on the edge of Montreal in Canada.

This was a worry. It seemed so unlikely that the transmitter remained attached to a live bird – more likely, it had fallen off and was hanging on a branch. Just to make sure, Morales, a graduate student at McGill University, gave the berry-laden shrub a gentle shake – and then a flutter of feathers among the branches and shadows caught her eye. To her surprise, the thrush, very much alive and healthy, was hopping about the bush in protest at having been disturbed. This little bird had hung around for longer than she expected.

Swainson's thrushes migrate from northern areas to Central and northern South America every autumn. But some make a "pit stop" in and around cities such as Montreal. For a study published last month, Morales and her colleagues had been researching how Swainson's thrushes balance the need to migrate quickly – so as to maximise its benefits – with the need to refuel, such as by stopping over in places like Montreal. They caught and radio tagged a total of nearly 80 of the birds.

Continued below.
The strange reason migrating birds are flocking to cities

I saw probably a million Blue and Snow Geese migrating north today along the Missouri river. Maybe more. Uncountable V's in the air, fields full of resting or feeding birds, and great balls of flying birds going crazy. They fly up the Missouri and then off into Canada. I've seen them migrating south along the Red River of the North before but this is a first in this direction. They were North of Kansas City and south of Omaha. I am looking forward to the Sandhill Cranes in a month or so. These majestic birds park for over a week on the Platte River before going farther north. Hundreds of thousands of them.