At 07:16 AM 12/11/2006, Joe Subich, W4TV wrote:
> > Also, no differentiation between 1,000' high midwestern TV
> > towers, and 100' high cell towers. Might be interesting to
> > see if we're getting piles of bird carcases around cell
> > towers.
>They don't even get "piles of bird carcasses" around 1000' high
>midwestern TV towers. I spent 15 years around a 1200' TV tower
>- with strobes - us outside Columbus Ohio through he 80's and
>most of the 90's. That tower was responsible for the death of
>fewer than 2-3 dozen a year. We would see a couple per month in
>the spring and fall with none in the winter and a rare carcass
>during the summer months.
There IS a discussion in the literature about this. Given that the
bird strikes occur at night, local scavengers might haul away some
fraction of the carcasses.
Some researchers (in what I think is a very amateur radio like
improvisation, although not done under the aegis of a ham license)
took a marine X-band radar and turned it on its side, creating a
"vertical fan" beam in an attempt to quantify this sort of thing.
I suspect that there really IS a huge uncertainty in the estimates,
especially given all the confounding factors that come into play
(weather, migration paths, tower characteristics, bird species,
seasons and time of day).
>For DF&WS's "estimates" to be even in the ballpark, every one of
>the estimated 10,000 towers more that 800 feet tall in the US
>would have to claim 1000 birds a year ... In my opinion that
>number is simply not credible and is probably off by a factor
>of at least 10.
Perhaps, but, unfortunately for us, 4 million or 40 million, if it
provides an excuse for a local jurisdiction to require an analysis
that costs $10K, that's a pretty hefty burden for someone who puts up
a tower once every 10 years. (For a cell company installing
thousands, it's not such a big deal.. the overall installation is
bigger and more expensive than a ham tower)
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