Subject: Fw: Ken Parkes on dead birds (fwd)
Date: Sep 15 11:53:30 1994
From: Mark Holmgren - holmgren at LIFESCI.LSCF.UCSB.EDU

The following is Ken Parkes' response to a BIRDCHAT thread
forwarded to him regarding 'building kills'
From: Kenneth Parkes <parkesk at>
Thu, 15 Sep 1994 16:00:49 EDT
To: holmgren at
Subject: dead birds

Hallelujah! I have been talking up the importance of
accidental bird kills for years, as you know. But the
participants in the dialogue you sent me essentially confined
themselves to window kills (although cats were mentioned), and
stressed that this was largely an urban phenomenon based on
glass-sheathed high-rise buildings. What I have been
emphasizing all these years is the kills from TV transmission
and similar towers, many of which are far from urban areas.
Both the towers themselves and their guy wires appear to be the
killers, and we are talking about many, many thousands of
birds. As you know, we received dead birds from a team that
monitored a TV tower just outside Youngstown, Ohio, for years.
The "take" varied from year to year, probably owing to
meteorological conditions. In the worst autumn migration, we
received over 3000 dead birds, including 150 Ovenbirds killed
in one night. What people have also overlooked is that the
species most frequently killed in these collisions are night
migrants of precisely those groups about which everybody is
worried -- the neotropical migrants including wood warblers,
vireos, thrushes, Rose-breasted Grosbeaks, etc. It is my
contention that this source of mortality of neotropical
migrants may play a much larger role in their diminishing
numbers than habitat loss in the tropics. As I have pointed
out in many conversations, if an Ovenbird can't find the
woodlot where it wintered last year, it can keep looking -- and
we know that many North American migrants have adapted to
disturbed tropical habitats, so it may well survive. But when
an Ovenbird hits a tower (or a window) it is dead then and
there, whether male or female, adult or young, healthy or sick
-- it is dead. How can populations sustain a loss of 300
individuals in one night, if this sort of mortality rate
prevails at towers across the continent? Some of the symposia
have indicated that populations of Neotropical migrants do not
seem to have diminished significantly at some stations. This
could well be a function of whether or not there are killer
towers along the migration route that those particular breeding
populations follow. If you can get this message to the
multiple recipients from whom you received comments as sent to
me, I'd appreciate it. I expect to see you at the WFO meeting
later this month.

* Mark Holmgren E-Mail *
* Vertebrate Museum holmgren at *
* Department of Biology Phone (805) 893-4098 *
* University of California *
* Santa Barbara, CA 93106 Department FAX (805) 893-4724 *