The deaths of an estimated 5000 to 10,000 Lapland Longspurs in
the vicinity of a 420 foot communications tower complex in western
Kansas in January 1998 brought the issue of bird mortality at communications
towers to the attention of birders across the continent. Concern
has continued to grow due to the impending construction of many
tall towers to serve the new digital television medium, and the
proliferation of new towers across the continent in the past five
years for cellular phone service.
Night migrating birds are attracted to the lights on towers in certain
foggy or low cloud ceiling weather conditions. Mortality or injury
occurs when they strike the tower structure or the towers
relatively invisible supporting guy wires. In some cases so many
birds are attracted to the proximity of a tower that birds are killed
or injured when they collide with one another.
We have two long-term studies in Upstate New York which provide
some information on the species, temporal patterns, and numbers
of birds killed over the past three decades. One study was conducted
by Wilifred Howard at an 850 foot high TV tower in Elmira New York.
Large kills of over a 1000 birds were documented in a single night
on several occasions. Another ongoing study has been conducted for
over 35 years in the Buffalo area by Arthur Clark of the Buffalo
Museum of Science. Data from both studies indicate that mortality
occurs primarily in the fall in upstate New York, and that most
mortality occurs from mid September through the first week in October.
The number of towers in New York State has doubled since the mid
1980s, and is on track to double again by the year 2OlO. In the
last 15 months there have been more than 60 new towers built (200
feet tall or higher). With this rapid proliferation of towers there
is a need for more information. Broadcast and communications towers
are regulated by the Federal Communications Commission (FCC). Current
FCC regulations only require environmental assessment for new towers
when threatened or endangered species may be affected, or if the
tower is to be built in a wildlife preserve. Most towers going up
do not fall into one of these categories and no single tower will
have any huge impact on bird populations by itself. So the great
proliferation of towers on the continent today is largely bypassing
environmental review, and the accrued impact on our migratory bird
populations is not being considered.
While conducting additional long-term studies at specific towers
would be useful, a comparative study of mortality at many different
types of towers would be very helpful for understanding the breadth
of the problem. A concentrated effort from a coordinated group on
just a few targeted mornings (e.g., after nights of foggy weather)
could provide outstanding information - it might indicate how different
types of towers and tower lighting schemes, as well as how differing
characteristics of geographic location affect bird mortality at
towers. For example short towers in the 2-400 foot range are suspected
to kill far fewer birds than the larger towers over 500 feet high.
But what happens when these shorter towers are put on top of a hill?
Does that increase their hazard to night migrating birds? Also,
what is the relative bird hazard of towers with white strobe lights
vs. slow blinking red incandescent lights?
Such a comparative towerkill survey began in fall 1998. The initial
area of focus was in the area between Syracuse, Elmira, and Binghamton.
The survey operated with a hotline of volunteers activated on three
evenings when weather appeared likely to cause a bird kill. The
grounds under 15 towers were checked by volunteers early the next
morning. A few volunteers had permits to collect the carcasses and
these were salvaged for the vertebrate collections at Cornell University
and the Buffalo Museum of Science. Though the weather conditions
were generally not conducive for causing bird mortality last fall,
21 bird carcasses were documented.
This fall the survey has expanded to include a larger portion of
New York State. The survey will serve to make the communications
industry aware of the issue and to provide them with useful information
on bird friendly tower design and locations for siting future towers
in order that bird kills in Upstate New York are minimized. Bird
carcasses will be salvaged for science when possible. Large kills
will be sent to Ward Stone at the NYS DEC for his studies on pesticides
in bird tissues. We are also working on coordinating with wildlife
rehabilitators so that any injured birds may be saved. For more
information, or to participate in future surveys contact:
NYS Tower Survey
P0 Box 3911
Ithaca, NY 14852