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Survey of Bird Mortality at Communications Towers in Upstate New York

(Originally published in New York Birders, Vol. 28, No. 4, October 1999)

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 tower’s 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:

Bill Evans
NYS Tower Survey
P0 Box 3911
Ithaca, NY 14852

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