Posts Tagged Trauma
So says a current television commercial trying to convince drivers to slow down. A recent study indicates that this will save not only human lives but avian ones as well. It seems that birds are able to calculate the average speed that cars travel along certain stretches of road and adjust their flight initiation distance accordingly (http://www.sciencenews.org/view/generic/id/352603/description/Birds_know_road_speed_limits).
On stretches of road with a speed limit of 20 kilometres per hour, birds waited to fly until the car was about 10 metres away. That distance increased to roughly 25 metres on roads with a 90 km/h limit and around 75 metres at a 110 km/h limit. Consequently a speeding car will reach the bird earlier than it expects, making it more likely to be struck. Yet another reason to slow down and stick to the speed limit.
Over the years I have seen many avian road trauma victims. Recently I have begun peering into the eyes of these injured birds. Intriguingly a number of them have long standing retinal damage presumably reducing their visual acuity and field of vision. I wonder if many of the birds that are struck on roads become victims because their eyesight is compromised. To study this properly I would need to compare the injured birds with a sample of healthy wild caught birds. Something for the future.
Dr. F. Bunny
Legagneux, P., and S. Ducatez. 2013. European birds adjust their flight initiation distance to road speed limits. Biology Letters. Published online August 21, 2013. doi: 10/1098/rsbl.2013.0417.
WASHINGTON — Wind energy facilities in 10 states have killed at least 85 golden and bald eagles since 1997, says a new government study.
Just in the last five years, wind farms have killed at least 67 eagles, but the figure could be much higher, the study says.
The research represents one of the first tallies of eagle deaths attributed to the nation’s growing wind energy industry, which has been a pillar of President Barack Obama’s plans to reduce the pollution blamed for global warming. Wind power releases no air pollution.
But at a minimum, the scientists wrote, wind farms in 10 states have killed at least 85 eagles since 1997, with most deaths occurring between 2008 and 2012, as the industry was greatly expanding. Most deaths — 79 — were golden eagles that struck wind turbines. One of the eagles counted in the study was electrocuted by a power line.
The vice president of the American Bird Conservancy, Mike Parr, said the tally was “an alarming and concerning finding.”
A trade group, the American Wind Energy Association, said in a statement that the figure was much lower than other causes of eagle deaths. The group said it was working with the government and conservation groups to find ways to reduce eagle casualties.
Still, the scientists said their figure is likely to be “substantially” underestimated, since companies report eagle deaths voluntarily and only a fraction of those included in their total were discovered during searches for dead birds by wind-energy companies. The study also excluded the deadliest place in the country for eagles, a cluster of wind farms in a northern California area known as Altamont Pass. Wind farms built there decades ago kill more than 60 per year.
“It is not an isolated event that is restricted to one place in California, it is pretty widespread,” said Brian Millsap, the national raptor coordinator for the U.S. Fish and Wildlife Service, and one of the study’s authors.
The study excluded 17 eagle deaths for which there was not enough evidence. And, in a footnote, it says more golden and bald eagles have since been killed at wind energy facilities in three additional states — Idaho, Montana, and Nevada.
It’s unclear what toll the deaths could be having on local eagle populations. And while the golden eagle population is stable in the West, any additional mortality to a long-lived species such as an eagle can be a “tipping point,” Millsap said.
The research affirms an AP investigation in May, which revealed dozens of eagle deaths from wind energy facilities and described how the Obama administration was failing to fine or prosecute wind energy companies, even though each death is a violation of federal law.
Documents obtained by the AP under the U.S. Freedom of Information Act show that in two cases in Iowa federal investigators determined that a bald eagle had been killed by blunt force trauma with a wind turbine blade. But neither case led to prosecution.
In one of the cases, a bald eagle was found with a missing wing and a leg in a corn field near a turbine at EDP Renewables North America LLC’s Pioneer Prairie facility in Iowa. But the report says, “due to the sensitive nature of wind farm investigations and the fact that this investigation documented first violation for EDPR in Midwest, no charges will be pursued at this time.” The report lists four other golden eagle deaths at a wind farm operated by the company in Oregon. The company did not return emailed questions about the incidents from the AP.
The Fish and Wildlife Service, which employs the six researchers, has said it is investigating 18 bird-death cases involving wind-power facilities, and seven have been referred to the Justice Department. The authors noted the study’s findings do not necessarily reflect the views of the agency, although some of their data was obtained from staff.
Meanwhile, the wind energy industry has pushed for, and the White House is currently evaluating, giving companies permission to kill a set number of eagles for 30 years. The change extends by 25 years the permit length in place now, but it was not subjected to a full environmental review because the administration classified it as an administrative change.
Wind farms are clusters of turbines as tall as 30-story buildings, with spinning rotors as wide as a passenger jet’s wingspan. Though the blades appear to move slowly, they can reach speeds of up to 170 mph at the tips, creating tornado-like vortexes.
Wind farms in two states, California and Wyoming, were responsible for 58 deaths, followed by facilities in Oregon, New Mexico, Colorado, Washington, Utah, Texas, Maryland and Iowa.
In all, 32 facilities were implicated. One in Wyoming was responsible for a dozen golden eagle deaths, the most at a single facility.
The research was published in the Journal of Raptor Research.
In a world of climate change we are all (well, maybe not the coal and oil companies) looking for alternative ways to generate energy that do not produce greenhouse gases. It seems ironic that the nuclear industry has seen this as a potential opportunity to appear green and a viable alternative to coal power. Apart from the fact that plutonium is still deadly for 250,000 years and countries like Germany appear to be winding their nuclear programs down in the wake of the Fukushima disaster, nuclear is no more sustainable than coal or oil. Uranium will run out just like all the fossil fuels, so why go down a potentially lethal path for the sake of a few years of power? Forget the nuclear nonsense and head straight to the technologies that will keep my computer alive and active long after I’ve nourished a few thousand worms.
Which brings me to wind farms and turbines. As usual, a lot of nonsense is being spouted by both sides. One memorable newspaper article described opposition to turbines because they would negatively affect the migrating orange-bellied parrot, with a lovely full colour photo of the parrot accompanying the article (http://www.theage.com.au/articles/2006/04/05/1143916574751.html). Interestingly these turbines were destined for a site east of Melbourne, in an area not visited by OBPs, who prefer the saltmarshes west of Melbourne for their overwintering grounds.
Nevertheless turbines do kill birds and bats, 100,000 to 440,000 birds each year according to the US Fish and Wildlife Service (http://www.nature.com/news/the-trouble-with-turbines-an-ill-wind-1.10849), generally through direct collisions. This is, however, considerably fewer than are killed by cars (60-80 million), building strikes (100,000 to 1 billion), power lines (up to 175 million) and our old friend, the pussy cat (365 million to 1 billion). Very rubbery figures to be sure, but significant nonetheless.
Bats, however, die in a more interesting way. The movement of the propellers generates a significant area of low pressure behind the turbine (five to 10 kilopascals less than the surrounding air). As nature abhors inequality, when the unsuspecting bat flies into this low pressure region the relatively higher pressure inside its body attempts to equalise with the lower pressure outside its body. It does this by expanding outwards, which leads to ruptured blood vessels and lungs filled with blood (http://www.scientificamerican.com/article.cfm?id=wind-turbines-kill-bats). I can certainly attest to this, having necropsied affected bats. There are no external signs of damage but their chests are certainly full of blood, caused by this barotrauma.
What to do? Do we sacrifice some birds and bats on the altar of climate change, because none of us want to return to pre-electricity days but we also don’t want our planet to heat up? You can’t make an omelette without breaking eggs, and all that. Rather than scrap a potentially important source of sustainable power one suggestion is to be smarter about placing wind turbines away from bird and bat flight paths in the first place. While this is sensible in principle we don’t know enough about their pathways to make this work reliably.
What shows more promise is redesigning the turbines themselves. On a recent ski trip to Copper Mountain in Colorado I saw some wind turbines on the very top of the mountain. But these turbines were different to the traditional horizontal axis turbines we are all familiar with. They were vertical axis turbines. Instead of having a big propeller spinning on a pole, they had vertically orientated blades which spun around the central pole. I had never seen this design before, but it could be the answer. According to a report these vertical turbines are less dangerous than the horizontal ones because they don’t use propeller-like blades to capture the wind, but rotating open-framed cylinders (http://www.msnbc.msn.com/id/44627832/ns/technology_and_science-innovation/t/upright-turbines-breathe-new-life-wind-farms/). The downside is that they don’t generate as much electricity as the traditional turbines. However, according to the article, “putting windmills upright and spacing them more tightly together can generate more electricity on less land, and kill fewer birds or bats than traditional horizontal rotating wind turbines.” These vertical turbines are also only 30 feet high, which is below the migratory level for birds and bats.
It is amazing how resourceful we can be when we have to. It’s just a shame that resourcefulness only materializes when we are faced with a catastrophe. But that is how we operate, I guess. Why waste time on things that might happen, like Y2K, when there are so many things that are happening to worry about? It does make preventative medicine particularly hard to sell, however.
Dr. F. Bunny