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Index of Subjects --Apple-Mail-2--1044580369 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=ISO-8859-1; format=flowed Jim: the final numbers that you relayed initially sounded too high,=20 but an exactly 8% decline over exactly 40 years does indeed predict=20 that only 3.6% of the original population numbers should be left: the=20= 4% current population estimate relative to 40 years ago, 1969, would be=20= correct. A figure of 4% obviously indicates a 25-fold drop in numbers since=20 ~1969. Is this likely to mean that only 1 in 25 of the original=20 night-time roosts are still occupied in 2009 while 24/25 are now=20 vacant, because the swifts like to aggregate together, or is it simply=20= that all roosts are still occupied but with much reduced numbers (1/25=20= of the original numbers -- lonely times at night)? Or have a lot of=20 the roosts simply disappeared -- habitat destruction? What`s known about the losses, or at least what are the best current=20 guesses as to the cause(s)? Steve (Halifax) ************************************************ On 28-May-09, at 5:17 PM, James W. Wolford wrote: > Yes, indeed, negative data are always worth recording and=20 > documenting, despite the anxiety it produces in us hoping for some=20 > sign of an upward trend after Hurricane Wilma in late fall of 2005,=20 > which may have exacerbated the decline in North America and especially=20= > Canada over the past 40 years. =A0Check out the two-page article in = the=20 > latest and current issue of Bird Studies Canada's news magazine, which=20= > states that Canada's Chimney Swifts have been declining at the severe=20= > rate of 8+ % per year! for 4 decades and that their numbers represent=20= > only about 4% of their former abundance! > > So thanks, Linda and Ross, for your continuing efforts in monitoring. > > Jim in Wolfville > > > --------------------------- > > Begin forwarded message: >> From: Ross & Linda Hall <ross.hall@ns.sympatico.ca> >> Date: May 28, 2009 9:36:38 AM ADT >> To: Jim Wolford <jimwolford@eastlink.ca> >> Subject: Truro Chimney Swifts >> >> Jim >> I guess negative results are worth recording. >> =A0 >> Linda=A0& I checked the Agricultural College May 16 and 27.=A0 There = were=20 >> no swifts.=A0 Reported earlier there were 17 swifts on May 14. >> May 20 we watched the large chimney at the Colchester Hospital, also=20= >> checked the old YMCA chimney and one at the Stanfields factory but=20 >> saw no swift use. >> One sees the occasional swift flying about. >> =A0 >> Good to hear that other areas are having good swift numbers or the=20 >> Truro results alone would be very disturbing. >> It is strange that the the NSAC chimney has such low or no numbers=20 >> compared to several years ago. >> =A0 >> Regards >> Ross --Apple-Mail-2--1044580369 Content-Transfer-Encoding: quoted-printable Content-Type: text/enriched; charset=ISO-8859-1 Jim: the final numbers that you relayed initially sounded too high, but an exactly 8% decline over exactly 40 years does indeed predict that only 3.6% of the original population numbers should be left: the 4% current population estimate relative to 40 years ago, 1969, would be correct. =20 A figure of 4% obviously indicates a 25-fold drop in numbers since ~1969. Is this likely to mean that only 1 in 25 of the original night-time roosts are still occupied in 2009 while 24/25 are now vacant, because the swifts like to aggregate together, or is it simply that all roosts are still occupied but with much reduced numbers (1/25 of the original numbers -- lonely times at night)? Or have a lot of the roosts simply disappeared -- habitat destruction? =20 What`s known about the losses, or at least what are the best current guesses as to the cause(s)? Steve (Halifax) ************************************************ On 28-May-09, at 5:17 PM, James W. Wolford wrote: <excerpt> Yes, indeed, negative data are always worth recording and documenting, despite the anxiety it produces in us hoping for some sign of an upward trend after Hurricane Wilma in late fall of 2005, which may have exacerbated the decline in North America and especially Canada over the past 40 years. =A0Check out the two-page article in the latest and current issue of Bird Studies Canada's news magazine, which states that Canada's Chimney Swifts have been declining at the severe rate of 8+ % per year! for 4 decades and that their numbers represent only about 4% of their former abundance! So thanks, Linda and Ross, for your continuing efforts in monitoring. Jim in Wolfville --------------------------- Begin forwarded message: <excerpt><bold>From: </bold>Ross & Linda Hall <<<color><param>0000,0000,EEEE</param>ross.hall@ns.sympatico.ca</color>> <bold>Date: </bold>May 28, 2009 9:36:38 AM ADT <bold>To: </bold>Jim Wolford <<<color><param>0000,0000,EEEE</param>jimwolford@eastlink.ca</color>> <bold>Subject: Truro Chimney Swifts</bold> Jim I guess negative results are worth recording. =A0 Linda=A0& I checked the Agricultural College May 16 and 27.=A0 There = were no swifts.=A0 Reported earlier there were 17 swifts on May 14. May 20 we watched the large chimney at the Colchester Hospital, also checked the old YMCA chimney and one at the Stanfields factory but saw no swift use. One sees the occasional swift flying about. =A0 Good to hear that other areas are having good swift numbers or the Truro results alone would be very disturbing. It is strange that the the NSAC chimney has such low or no numbers compared to several years ago. =A0 Regards Ross </excerpt></excerpt> --Apple-Mail-2--1044580369--
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