More than 100,000 communication towers are estimated as occurring within the United States. These structures range in height from 200 to more than 800 feet. There is an estimated annual growth of 7-10 percent.
Each of these towers are registered with the Federal Communications Commission, making it possible to evaluate their occurrence and extent. The best site to view tower type and location is the towerkill.com website, which provides a map for each state in the continental U.S., and a tally of the types of towers present in 1998, 2004 and 2001.
The following summary for four states in the northern Great Plains, readily shows the increase in towers, based upon a comparison of 1998 to 2010, as summarized from the towerkill.com information.
Kansas |
1998 |
2010 |
200-299 feet |
342 |
535 |
300-499 feet |
599 |
1002 |
500-799 feet |
60 |
71 |
800+ feet |
14 |
40 |
1015 |
1648 |
|
Nebraska |
||
200-299 feet |
212 |
330 |
300-499 feet |
344 |
560 |
500-799 feet |
35 |
44 |
800+ feet |
31 |
34 |
622 |
968 |
|
South Dakota |
||
200-299 feet |
149 |
209 |
300-499 feet |
142 |
241 |
500-799 feet |
18 |
26 |
800+ feet |
19 |
21 |
328 |
497 |
|
North Dakota |
||
200-299 feet |
200 |
260 |
300-499 feet |
179 |
342 |
500-799 feet |
17 |
27 |
800+ feet |
19 |
19 |
415 |
648 |
|
Overall |
||
200-299 feet |
903 |
1334 |
300-499 feet |
1264 |
2145 |
500-799 feet |
130 |
168 |
800+ feet |
83 |
114 |
Total |
2380 |
3761 |
Increasing numbers are readily apparent for other states and regions.
Examples of Bird Mortality
There are several prominent examples of bird mortality at communication towers. Some examples include:
1948: a large kill at a radio tower near Baltimore, Maryland
1955 and for 29 subsequent years: a minimum of 42,384 records, representing 189 species at a television tower at the Tall Timbers Research Station in northern Florida
1957 and for the subsequent 38 years: nearly 121,560 records for 123 species
1963: more than 12,000 birds retrieved from the base of a tall television tower in Eau Clair, Wisconsin
1972: reports of single night kills exceeding 1000 birds at television towers in Tennessee and Florida
1982 and subsequent years: variable numbers from 4,782 in 1982 to 6 in 1992 at three tall television towers in Buffalo, New York;
1983: 320 casualties, representing 40 species, during September 12-16, at the KCNA-TV Tower in Boone County, Nebraska; the specimens are now in the collection at Wayne State College.
2003-2005: multiple tower study, with 203 birds noted in spring 2005 at 24 towers, and 173 during the autumn at the same towers
2005: On September 7-8 and also on September 13-14, an estimated 400 birds killed each night at the 1,100 foot WMTV tower near Madison, Wisconsin.
2005: more than 500 killed in a three-night period during October at an 1,100 foot height tower near West Monroe, New York.
Further information on additional known tower kills is readily available at numerous online sources.
Based upon the extensive number of known towers of varying heights, and the relative few reports, it is obvious that little information is available on the probable, and wide-spread occurrence of mortality. The recent studies in Michigan are an exception, and further indicate how dangerous towers can be for migratory birds of many sorts. Similar results would result from similar efforts wherever towers occur.