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<b>On Behalf Of &l Hi Dave, others I too read this front page headlined piece 'Loon population in peril' but had a deeper problem with it -- it didn't seem to make sense as written. If the breeding success rate for a stable population (neither expanding nor shrinking) has been correctly estimated at 0.48 chick per pair per year, and yet the current success rate is higher, ~0.59 (from memory, can't find the paper to check), that means that the population actually is expanding modestly, so what's the problem (not explained)? If anyone here is familiar with the actual study perhaps they could comment and expand upon the C-H article to clarify the story. Presumably this was a reporter from a journalism background who can't do numbers, and failed to understand an important part of the original survey and so did not report it. Is it that the breeding success rate used to be (say) 2.0 (meaning an aggressively expanding population) and that this rate has been steadily declining, such that extrapolation from data over several recent years suggests that in (say) 3 years from now the rate will drop below 0.48? That would be worth reporting, though extrapolation is always dangerous. For instance, a real decline in the rate might reflect the downward slope of a cyclical process which has yet to turn back up again, though I'm not suggesting grounds for optimism, given stories about lead sinker poisoning and effects of mercury. Steve (Halifax) Quoting David & Alison Webster <dwebster@glinx.com>: > Hi Rick & All, July 22, 2013 > For birds that potentially have about 22 breeding years, 0.48 > chicks per year.pair for steady state made me wonder if this > reflects attrition or failed pairing due to a shortage of nesting > sites (Lakes). If so then 0.48 is a meaningless statistic. > > Some years ago, early morning antics at Sunken Lake suggested > that the residents were declaring ownership of the lake in no > uncertain terms (sequence pasted below). > Yt, Dave Webster, Kentville > > START OF PASTE\\\\\\\\\\\\\\\\\\\ > Hi Dusan & All, Aug 19, 2003 > We saw similar strange antics in 2001, at about this time of year, > and I described them in a post of Aug 6, 2001 (pasted below with also > strange typos intact). A week or so later we saw a similar display. > Failing other ideas I thought it might be the loon equivalent "This > is my lake, buzz off". > DW > > \\\\\\\\\\\\\\\\\\\START OF PASTE > > Dear All, Aug 6, 2001 > On Saturday at Sunken Lake, Kings Co., we were surprised to > see two sets of young loons (1 small loon and 2 slightly larger > imm. loons) and at least three matures, having understood that > there is normally only one loon nest per small lake. > On Sunday morning, at about 8:00 a.m., we saw the > repercussions (perhaps) in the form of a showdown between two > adult loons, most of it obligingly staged within 200 yards of our > cottage. One loon (L1) flailed into view at the head of a cloud > of spray, that was raised by both wings hitting the water > vigorously, and within seconds a second loon (L2) followed. When > L2 got to within ~5 body lengths of L1, the chase began in the > form of a zig-zag, i.e. when L2 narrowed the gap too rapidly and > was almost withing striking distance, L1 would turn abruptly on > one wing, L2 would shoot harmlessly past and be ~8 body behind by > the time it got turned around again. At least once, L1 did a 180 > and started chasing L2. A third adult loon was nearby while this > was going on, and make low un-loon-like worried 'whoo' sounds at > intervals. There was only one strike and there was so much water > flying I could not be sure that there was contact. > The chase lasted at least ten minutes (watch not nearby) and > ended when the lead loon dived. Several minutes later the tail > loon dived and within the next 1/2 hour a loon took off, circled > the lake and then crossed it to fly to the NW. Several minutes > later a second adult loon did the same. > Are immature loons able to fly by now ? > Yours truly, Dave Webster, Kentville > > \\\\\\\\\\\\\\\\\\\ first END OF PASTE > > Dusan Soudek wrote: > >> Hi, >> a friend reports the following loon behaviours from Keji last weekend. >> Can anyone explain what went on here? >> Dusan Soudek >> ............. >> Interesting experience at Site 24: More than 20 loons were flocking >> together rushing back and >> forth across Minards Bay honking, squawking and running and flapping >> across the water. They >> would submerge as a group and then pop-up elsewhere and repeat the loud >> activity again and >> again. This went on for hours. Sometimes they would break into two >> similar size groups but >> all tended to travel to the same location. About 7pm they were all >> gathered down near our >> site and started their recognizable forlorn loon call but all of them at >> the same time! >> Amazing! Unfortunately a large thunder shower cut them short. >> > > END OF PASTE\\\\\\\\\\\\\\\\\\\\\\ > ----- Original Message ----- > From: Rick Ballard > To: NatureNS > Sent: Monday, July 22, 2013 7:27 PM > Subject: [NatureNS] Loon Flotilla > > > After reading the Chronicle Herald article "Loon population in > peril", I thought I would post this photo of a Loon Flotilla, taken > this weekend at Indian Harbour Lake, Guysborough Co. The photo shows > a group of 6 mature loons. Also seen the same day, probably not in > the group photo, were the resident pair with their half grown chick. > So possibly there were 9 loons on the lake at once. The lake > generally has a single resident pair, and is about 5km long by less > than 1km wide. > > > -- > Rick Ballard > Dartmouth,Nova Scotia, Canada
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