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Majka<BR><B>Sent:</B> Wednesday, December 19, 2007 4:38 PM<BR>< --Apple-Mail-2-759376315 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Hi Lance, On Dec 19, 2007, at 7:49 PM, Laviolette, Lance (EXP) wrote: > Hi Chris, > > The methodologies used by the Breeding Bird Surveys (BBS) and the > first Maritime Breeding Bird Atlas to estimate populations are much > different. The first atlas had nothing comparable to the point > counts of the current atlas so had to rely on people taking > educated guesses about the abundance of a species in their square > (s). It's been a long time since I took part in the first atlas > but I seem to recall that there were 5 or 6 fixed levels and the > estimate was optional. The BBS provides a count of all birds seen > or heard over a fixed duration along a route composed of 50 points. > Given the completely different methods used its not surprising that > numbers differ so radically. It will be very interesting to see the > results of this atlas's point count information as it is much > closer in methodology to that of the BBS. The methodologies are indeed quite different and both have certain strengths. The BBS approach is a good one, but as you say, if there are only ~ 30 routes in the province this requires considerable extrapolation over the area of the province. The Atlas approach was a five year snapshot in time, but there was a very considerable effort (43,093 party hours) over the entire region. > > I'm not sure how the atlas indicates that the populations of both > Belted Kingfishers and American Robins is stable or how you can > definitively state that the BBS estimates are too high. They are high in relation to the Atlas projections. I'm in no position to be able to evaluate the statistical reliability of these approaches in relation one another. The USGS site itself says, "Most of you realize that analysis of BBS data can be controversial." ;-> > The BBS trends are based on annual measurements of the same data > collection points over 40 years. The first atlas was one snapshot > in time. What are the estimates of the first atlas being compared > to, the preliminary estimates of the current atlas? In both cases the Atlas relies on BBS data. ;-> For American Robin they say, "The BBS indicates stable numbers since 1966," and for Kingfisher, "The BBS shows no significant population trend since 1966." Cheers, Chris > > All the best, > > Lance > From: naturens-owner@chebucto.ns.ca [mailto:naturens- > owner@chebucto.ns.ca] On Behalf Of Christopher Majka > Sent: Wednesday, December 19, 2007 4:38 PM > To: naturens@chebucto.ns.ca > Subject: Re: [NatureNS] Too many kingfishers in Nova Scotia?? > > Hi Lance, > > On Dec 19, 2007, at 1:35 PM, Laviolette, Lance (EXP) wrote: > >> Hi Elizabeth and others, >> >> The 'estimated' population for whatever region is being asked >> about is based on the results of Breeding Bird Surveys (BBS). >> There are about 30 in Nova Scotia I believe. 16,000 (individuals >> not pairs) is not all that large an estimate for Belted >> Kingfishers really, when you consider a species such as American >> Robin will get you an estimated population of 3,000,000 for Nova >> Scotia. Also, it looks to me as though the estimated number is >> +/- %20. > > The Atlas of Breeding Birds of the Maritimes Provinces gives a Nova > Scotia population of Belted Kingfishers of 4,100 +/- 1,600 pairs > and a Nova Scotia population of American Robins of 370,000 +/- > 130,000 pairs. If the above estimates you are referring to derive > from BBS data then they are approximately 60% to high for > kingfishers and 340% too high for robins. > >> >> As far as the long term trend goes, you can go directly to the BBS >> trend analysis page and have a look at the data. It is found at: >> http://www.mbr-pwrc.usgs.gov/bbs/trend/tf06.html >> >> Since we're talking about Belted Kingfishers, the trend in Nova >> Scotia over the last 40 years is -4.67% (p=0.01) > > The Atlas indicates that populations of both species seem to be > stable. > > Cheers, > > Chris > >> Christopher Majka Nova Scotia Museum, 1747 Summer St., Halifax, Nova Scotia, Canada B3H 3A6 c.majka@ns.sympatico.ca --Apple-Mail-2-759376315 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 <html><body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; = -webkit-line-break: after-white-space; "> Hi Lance,<div><br><div><div>On Dec 19, 2007, at 7:49 PM, Laviolette, = Lance (EXP) wrote:</div><br = class=3D"Apple-interchange-newline"><blockquote type=3D"cite"> <div = dir=3D"ltr" align=3D"left"><span class=3D"256532423-19122007"><font = face=3D"Arial" color=3D"#0000ff" size=3D"2">Hi = Chris,</font></span></div> <div dir=3D"ltr" align=3D"left"><span = class=3D"256532423-19122007"><font face=3D"Arial" color=3D"#0000ff" = size=3D"2"></font></span>=A0</div> <div dir=3D"ltr" align=3D"left"><span = class=3D"256532423-19122007"><font face=3D"Arial" color=3D"#0000ff" = size=3D"2">The methodologies used by the Breeding Bird Surveys (BBS) and = the first Maritime Breeding Bird Atlas to estimate populations are much = different. The first=A0atlas had nothing comparable to the point counts = of the current atlas so had to rely on people=A0taking educated guesses = about the=A0abundance of a species in their square(s).=A0 It's been a = long time since I took part in the first atlas but I seem to recall that = there were 5 or 6 fixed levels and the estimate was optional. The BBS = provides a count of all birds seen or heard over a fixed duration along = a route composed of 50 points. Given the completely different methods = used its not surprising that numbers differ so radically. It will be = very interesting to see the results of this atlas's point count = information as it is much closer in methodology to that of = the=A0BBS.</font></span></div></blockquote><div><br = class=3D"webkit-block-p