More than just a Ham radio blog.
is an informative, cynical and sometimes humorous look at what is happening in the world of amateur radio.

Saturday, 18 July 2009

Radar saves bats and birds

I like bats. Maybe watching Adam West prancing about in his tongue in cheek interpretation of the Dark Knight had something to do with it. I remember running around the playground with my duffel coat fastened by one toggle and fashioned in to a cloak. Possibly it was finding one stunned and distressed, after an encounter with a cat, that clung gently to my finger and let me get a good close look at it while it came around. Probably it was simply a boyhood fascination with whatever other people found repulsive, snakes, spiders, lizards, and bats.

I do not like wind farms. Obscene scars on the landscape that cause more environmental damage than any of the tree huggers will admit. Massive swathes of beautiful countryside are torn up to put in access roads so they can be built and maintained with little or no thought as to how the wildlife will cope. Delicate and rare species of plant trampled and wiped out by construction vehicles. People worry about plastic bags not decaying but the construction materials used in the blades of wind turbines could mean they will still be with us in 10,000 years. Even off shore farms destroy massive areas of seabed and with it sea life. When the wind is on shore they lead to horrific levels of noise and sleepless nights for those living near.

Bat and bird populations can be significantly effected by collisions with turbine blades. A six-week study at two wind farms in the US recorded more than 4,500 bat deaths. "This is a major problem in the States, especially during the bats' migratory period," said Paul Racey of the University of Aberdeen, which undertook the study. The Department for Environment, Food and Rural Affairs recently commissioned a three-year study to gather data on the effect wind farms are having on bats in the UK.

There may be a solution to this problem however; Peñascal wind farm in southern Texas is currently using radar to prevent migrating birds from flying into it. Researchers discovered that a stationary beam reduced bat activity near the turbines by almost 40%. Scientists don't know why bats avoid radar signals. One explanation is that radar energy warms the bats' wings "like a kitchen microwave" said Racey. Another theory suggests the bats' ears heat up, causing them to "hear" the radar signal as a clicking sound.

Racey has a number of ideas for improving the effectiveness of the method in an attempt to reduce collisions by 80-90%, they include a rotating beam and altering the pulse timings.

I am glad to see that an attempt is being made to save these fascinating creatures and that radio might have a hand in their salvation, but I would rather these eyesores were condemned to the bowels of hell.
One thing that makes me wonder if this idea might be bunkum however; I have a bat colony living close by and I can watch them circling my antennas hunting insects at dusk. I have never seen any signs of them avoiding my property while I have been transmitting even on the higher frequencies such as 23cms.

Visit the Bat Conservation Trust

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