This thread seems to be setting in early, this year. Usually it's
much closer to Dayton time. heh.
quoth KK8ZZ:
The mechanisms involved in migration by various species remain poorly
understood, whether magnetic fields or celestial navigation (night) or light
polarization, landmarks, magnetic fields, regional low frequency sounds or
other means (day), most migratory methods seem to lead massive flocks of
individual or mixed species along "ancestral" migration routes. When we put
up a tall tower, they fly into it.
-0-
To which I will append....how is it that nobody addresses the multi-megawatt
ERP's at SHF frequencies? It's well known that there are regular bird
deaths
from exposure to TV emissions on the Empire State Building. Or, at least
there used to be, the summer I was a transmitter tech.
I must say that Bob's indication that the estimated losses are 40-50Million
annually, makes more sense, as compared with the reported NFWS 4-50M. The
latter
must be a typo.
On the other hand, I think there's a lot of extrapolation going on.
If one Kansas, 1000' TV tower with megawatt ERP killed 10,000 birds in
one night....and there are 77,000 towers....oh, my God, think of the
carnage!
I repeat my personal observation, echoed by cell phone techs who are
hams: I have not seen piles of birds around cell sites. It's not
happening. The magnitude of the problem, and the nature of the problem
is not yet understood. It may be restricted to certain avian flyways,
certain high towers, and certain power levels.
n2ea
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|