In a message dated 3/28/03 2:01:27 PM Central Standard Time, jwcoffey@xxxxxxxxxx writes: > North American species apparently in decline according to Breeding Bird > Survey (BBS) data. > I was hoping someone could answer to the following question. BBS are fixed routes run over many years (The above report was just a 10 year period) how do they adjust or justify the numbers when there is a tremendous generational change in habitat along most routes that I know. Some formally rural routes are now settled. Some agricultural routes which once sported wide fence rows now are farmed to the fence lines. Generally, farm practices in regions change, such as extensive flooded rice fields where there had been cotton or soybeans. Tree farms where there had been mixed hardwoods. Once fallow fields are grown up in trees. If the exact habitat is not present over these periods then the exact birds surely are not present. I do not deny a decline in many species but of those listed I have seen habitat changes shift the concentrations from one location to another. Therefore a species can increase or decrease on a route but the species numbers stay the same in the area. If you are looking for Red-headed Woodpeckers in an area where the prime older woods have been clear cut and it is now new growth, you are not going to find them, but 2 miles away in another woods that has matured or been selectively cut you will find plenty. It's habitat, habitat, habitat. Just as others, I have seen marked increases in some of the species listed in my area in the 20 plus years I've been birding. I'm sure they have a mechanism that adjusts for this habitat change but I would like to know how it works. Good Birding!!! Jeff R. Wilson OL' COOT / TLBA Bartlett Tenn. =================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 =========================================================