Mass migration: the reason birds are flocking to cities
Back to basics -
The very fact that many species of birds migrate is common knowledge. In fact, it’s one of the first phenomena we learn about in biology class.
As kids, we learn that every year flocks of birds move from their breeding (summer) homes to their nonbreeding (winter homes), in search of food and shelter.
Did you know? -
It is less well known, perhaps, that as they move from A to B, many species of birds make pit stops along the way.
Dropping feathers - Often they molt (the process by which they shed and regrow some of their feathers), which is the equivalent of changing the tires on your car.
Big city life -
Perhaps unexpectedly, many of the pit stops that birds make during their migration are in urban locations.
Piqued interest -
Scientists are very interested in why birds are attracted to cities. To quote Morales, “It’s pretty amazing that this small green area can support a bird for 40 days.”
Leading theory -
According to Barbara Frei of Environment and Climate Change Canada, a department of the government of Canada, it may have a lot to do with light.
Wealth of evidence -
Indeed, there is ample evidence dating back more than 100 years to suggest that birds are naturally drawn to sources of light.
One of the earliest recordings of this phenomenon was made by the turn of the century Irish anatomist and ornithologist Charles Patten.
Nowadays, millions, perhaps even billions, of birds die every year as a result of crashing into lit-up buildings.
What does it all mean? -
The fact that cities are so treacherous to migratory birds has left scientists wondering what we can do to make them safer.
The obvious solution -
The main suggestion made so far is to try and reduce the amount of light emitted in urban areas. Of course, much of the light in cities is unnecessary.
Simple remedy -
According to Frank La Sorte at Cornell University, the simple act of turning off more lights at night could save the lives of thousands of birds.
Can trees help? - There is also research to suggest that migratory birds fare better in cities that have adequate tree cover.
Strong habitat -
Well-watered and mature trees can provide a habitat for hundreds of insect species, and are therefore great for birds that are insectivores.
It goes without saying -
Planting a few trees in an urban area should never be considered compensation for the destruction of natural bird habits.
All in all -
That said, it does seem that birds are and will continue to be attracted to cities, and that there are things we can do to make our cities more accommodating to them.
Food for thought -
So when you’re getting ready for bed tonight, remember to turn off your lights. You might just save the life of a bird!