Dennis,

I'm a bit skeptical of such statistical extrapolations. Rich Stallcup
estimated some similar figure as house cat mortality. If we added up all
the estimates for each supposed cause of death we might find twice as
many were supposedly killed than we thought to exist. Perhaps such
mortality is concentrated in such well lighted and exceptionally tall
built areas, which represent a very small fraction of the total area
traversed by the mass of migrating birds?

Gene Hunn (hunn at u.washington.edu)


On Tue, 6 Sep 1994, Dennis Paulson wrote:

> >Hi Dennis,
> >
> >Has anyone looked at the tremendous toll of birds in cities because of the
> >increased used of glass for patios, balconies etc? on houses and apt bldgs?
> >Got a feeling this is another huge toll that has crept up on us.
> >M. Price
> >michael_price at mindlink.bc.ca
>
> Yes, there's getting to be a body of literature about window kills. I
> believe the most recent estimate is something like 1-10
> birds/year/building, leading to a staggering estimate of 100 million to 1
> billion birds per year killed by window strikes in the U.S. alone; I
> imagine a few birds hit windows in Canada too. It's a huge toll, and it
> probably occurs more in the countryside--where there are a lot more
> birds--than in the cities. One estimate of bird populations in the U.S. is
> 20 billion, so this represents a more-than-trivial source of mortality. The
> reference is in Journal of Field Ornithology 64: 302-309, 1993.
>
> Dennis Paulson
>
>
>