The conventional wisdom is of course that DDT builds up at higher concentrations in birds at the top of the food chain. This includes the raptors and wading birds, which suffered major declines after DDT was introduced in the 1940's. Recovery only began after DDT was banned in 1972 in the U.S. and in Canada in 1973, and requiring more years while DDT and its derivatives dissipated from the environment. As an example, records of Reelfoot National Wildlife Refuge list 14 Bald Eagle nests for Reelfoot Lake in each of 1954 and 1955 (I estimate that roughly half that many nests were occupied throughout the nesting seasons, based on Albert Ganier's report during that era). After only one known STATEWIDE successful eagle nest in 1961 (at Lake Isom, 5 miles south of Reelfoot Lake), there were no known fledged Bald Eagles in Tennessee until 1983, when one young Bald Eagle fledged near Dover, Tennessee. The release of hacked Bald Eagles (287 in Tennessee during 1980 - 2003) and a few other rare raptors has sped up the recovery of these species. Troy Ettel has reported that 76 young Bald Eagles have been recorded in 43 Bald Eagle nests in Tennessee during 2002 (compared to 60 young fledging from 36 nests in 1999). Late eagle nesting reports have usually been received well past this date. The once huge heronries of Reelfoot Lake also virtually disappeared during these periods. Wading birds have obviously made comebacks since the late 1970's. In 1996, Dr. Fred Alsop provided the following two further examples (and more), as related to the Great Blue Heron and Great Egret of Tennessee: Great Blue Heron - "The breeding colonies in West Tennessee decreased steadily since the early part of this century, but their decline has been most dramatic from the 1950's to the mid-1970's. At Reelfoot Lake in 1938 there were over 1000 active nests of 5 species of herons at "Cranetown" of which over 300 belonged to the Great Blue Heron. 1959 was the last big year for the colony with about 200 nests. By 1962 there were only 3 nests, and the following year there was none." Great Egret - "Much reduced since the late 1930's and early 1940's in Tennessee. At Reelfoot Lake in the late 1930's the bird was very common; an estimate of 3500 on the lake was thought to be "conservative" and there were over 650 nests. By the early 1960's this colony and others had "crashed" and many were defunct. For more than a decade Great Egrets were not found nesting in Tennessee. They reestablished small breeding colonies in the late 1970's and these colonies continue to slowly grow." Since songbirds are not at the top of the food chain, it would not be surprising that they would be relatively unaffected by DDT. However, the evidence is very convincing that DDT had a major negative impact on birds at the top of the food chain, at least in the United States. We can be thankful that there are now better alternatives than DDT for fighting mosquitoes and the West Nile Virus, which will be a challenge at best. Bob Hatcher Brentwood, Tennessee =================NOTES TO SUBSCRIBER===================== The TN-Bird Net requires you to sign your messages with first and last name, city (town) and state abbreviation. ----------------------------------------------------- To post to this mailing list, simply send email to: tn-bird@xxxxxxxxxxxxxx ----------------------------------------------------- To unsubscribe, send email to: tn-bird-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Topographical Maps located at http://topozone.com/find.asp * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Visit the Tennessee Ornithological Society web site at http://www.tnbirds.org * * * * * * * * * * * * * * * * * * * * * * * * * * * * * TN-Bird Net Owner: Wallace Coffey, Bristol, TN jwcoffey@xxxxxxxxxx (423) 764-3958 =========================================================