By John McFerrin
For a migratory bird, life is no picnic. Many of them travel thousands of miles. Even if they can escape natural predators and overcome exhaustion, they still have to avoid power lines, wind turbines, oil and gas ponds, etc. along the way.
Occasionally, however, there are bits of good news:
Painting wind turbine blades
According to a study published in the journal Ecology and Evolution, bird mortality from collisions with wind turbines was reduced by about 70% by painting one of the three turbine blades black. The explanation for this result is found in an optics phenomenon called “motion smear.” This is a technical term in optics, having to do with how a bird, human, whatever perceives the world. In the context of this study, it means, more or less, that birds can more easily detect spinning wind turbine blades and recognize them as an obstacle to be avoided if one of the blades is black.
The possibility that painting blades could affect bird-blade mortality was suggested at least as early as 2002 when some laboratory researchers tested blades of different colors against different backgrounds. The more recent study tested this idea in the field with intriguing results.
The study is limited by its small size. Data was collected on six wind turbines in Norway, one with a painted blade and five without the painted blade. The result was that the painted turbine had 71% fewer bird deaths. The facility had been keeping records of bird deaths for about ten years so it had a good idea of how many bird deaths it was experiencing.
The species most prevalent in the study are not common in North America if they exist at all. Researchers suggest more study to determine if these observations are generally applicable or are somehow limited to Norwegian birds at one site.
Incidentally, this is the kind of relatively inexpensive measure that the Migratory Bird Treaty Act (as it existed before the Trump administration roiled things, see stories in the April, 2020, and February, 2021, issues of The Highlands Voice) could promote. The Fish and Wildlife Service, which administers the Act, only rarely prosecutes. Instead, it nudges and suggests, working with companies to avoid bird deaths.
If the idea of painting one turbine black does prove effective in other studies, it is the kind of thing that Fish and Wildlife Service would start suggesting that companies implement.
Turning down the lights in Philadelphia
When birds migrate, many species use the stars to navigate. On cloudy nights, they can get confused by city lights. They end up slamming into buildings with disastrous results.
Now Philadelphia is doing something about this. At the urging of several groups, it has begun a voluntary program to dim or turn out many internal and external lights during times of heavy migration. The program runs from April 1 through May 31 and from August 15 to November 15. Property managers and tenants are asked to voluntarily switch off lights between midnight and 6 a.m., especially in a building’s upper levels, lobbies and atriums.
The program is voluntary. Even so, the Building Owners and Managers Association of Philadelphia, which represents over 475 members who own or manage commercial properties or provide services to buildings, said the response has been “extremely robust.”
Common yellowthroats, white-throated sparrows, gray catbirds and ovenbirds are the most common victims in Philadelphia.