migration

City Lights Throw Migrating Birds Off Course

New research out of the University of Windsor indicates that bright city lights may cause migrating birds to zigzag rather than follow the (darker) course they might otherwise take. 

The team, headed by professor Dan Mennill, began their research by accident. Sound recording boxes had been placed around the area during a migration study, and the team noticed that the ones situated near well-lit—urban—areas picked up more bird vocalizations than the ones in dark—rural—ones. Further analysis revealed that more than three times the number of vocalizations occurred in the lit areas than in the unlit areas, indicating that three times more birds passed through the former than through the latter. Why? Perhaps because the lights made it difficult for them to see the stars by which they'd ordinarily navigate. 

Being drawn off course causes two problems for migrating birds. First, flying a less-than-direct route uses more of a bird's energy stores than flying a direct route; therefore, birds arriving at their destination are more depleted than they ought to be. Second, flying in a zigzag takes longer than flying directly, which means birds arrive later than they otherwise would—and perhaps miss a key food source or mating period. 

What can we do to help restore natural migration routes? For starters, we can turn off any unnecessary outdoor lighting at night. Mennill's team is researching other options, such as changing the intensity of street lights. Whatever they come up with, we're all for it. 

Now Starring: No American Birds

When we birders watch films and TV shows made in America, we often say, "Wha-?" We notice that the birds onscreen in a show supposed to take place here are actually foreign birds. No, it's not because of Hollywood sloppiness. It's because of the law. 

The Washington Post explains: The federal Migratory Bird Treaty Act (MBTA) of 1918 prohibits the possession of migratory birds for commercial purposes. This means it's illegal to keep domestic bird species as animal actors. Why? Steve Holmer, a senior policy advisor at the American Bird Conservancy, says that, before the MBTA, populations of some birds were severely harmed because they were used so often commercially. Snowy egrets, for example were decimated in the early 1900s because their plumes were used to decorate hats.

Are you surprised that native birds can't be used as actors? So were we, and so are many producers. Benay Karp, owner of Benay’s Bird and Animal Rentals in Woodland Hills, California, says producers often come to her looking to rent a native bird and leave with one that looks similar but actually isn't the genuine article. 

The good news is that egret numbers have rebounded, along with those of many other species. The Migratory Bird Treaty Act has been a success, and Hollywood is still abiding by it. 

The bad news is that birds are being used in film and television that aren't native to the United States. Not only is it expensive to import a non-native bird, but it also can't be pleasant for the bird. We here at Talkin' Birds are rather conservation-minded; we don't want birds from anywhere to be harmed. 

Now, how about when we hear the wrong bird in a film or TV show? Is that also because of the MBTA?

No. That really is because of Hollywood sloppiness. 

 

Migration Knows No Boundaries—and That's a Problem

Imagine you're a migrating bird. You've got to get to your winter home by molting season. You and your flock need to stop and refuel. Your senses and your memory tell you that this very spot is where you landed last year for water and a quick bite. But what's that? A parking lot? Now what are you going to do? 

A new study in the journal Science reveals that more than 90 percent of migrating birds find themselves in this situation (and worse) because of poorly coordinated conservation efforts around the world. Of the 1,451 bird species studied, 1,324—91 percent—traveled through areas that were not safeguarded from development. This means these birds may well have encountered the situation above. Further, eighteen species found themselves in unprotected breeding areas, and two species had no protection anywhere they went. 

“Migratory species cover vast distances and rely on an intact series of habitats in which they can rest and feed on their long journeys," conservation scientist Richard Fuller of the Australian Research Council's Centre of Excellence for Environmental Decisions (CEED) and the University of Queensland told the Associated Press. "If even a single link in this chain of sites is lost for a species, it could lead to major declines or even its extinction."

The United States and Great Britain signed the Migratory Bird Treaty in 1916 (with Great Britain signing for Canada) to protect birds that cross their international boundaries. Similar treaties have been made with Mexico (1936), Japan (1972), and Russia (1976). This is a good start, but habitat destruction is worst in North Africa, Central Asia, and the coastlines of East Asia. In these regions, the safeguarded areas—if any—do not overlap enough to provide a migration route for birds. One example of a bird at risk is the Bar-tailed Godwit. This well-traveled bird migrates from the Arctic to Australia and New Zealand, making stops in China, North Korea, and South Korea. Its population is dwindling because of the loss of habitat along its route.

The protection of migrating wildlife is a concern for all countries. We here at Talkin' Birds imagine it could bring about cooperation among people who don't usually cooperate. Meanwhile, if we could, we would donate all our frequent-flyer miles to the Bar-tailed Godwit.