I dont think this is correct. the "increase" in Maine is up from a few hundred birds in the entire state to a couple of thousand (on all counts), and that was only in one year. Similarly, most of the "increase" in North Carolina is due to a single data point. Counts of many tens of thousands have been recorded on the Great Lakes, on the USA/Canadian border in the Campobello Island, in Massachusetts and in North Carolina, mostly in the 1970s and 1980s, but with a few counts of this magnitude into the 1990s. There have been no records of any concentrations othis magnitude (tens of thousands) anywhere as far as we can tell, and I do not see how relatively small increases in Maine and North Carolina can account for these birds. i dont know what the basis of a "big increase" in Canada is, but that seems to conflict with the opinions of everyone in the USA who was followed these Bonapartes flocks for 20-40 years.
On Sat, Oct 17, 2020 at 4:56 PM David Nicosia <daven102...@gmail.com> wrote: > In Canada, they list Bonaparte's Gulls as having a "large increase". > > In Shai's graph of CBC you can see a definite decline of wintering BOGUs > from the 70s, 80s and 90s to the 2010s in the RI and LI areas. > https://www.flickr.com/photos/96951581@N02/50482248298/ > > I ran sea surface temperature departures from normal for the last 10 years > and you can see that the area centered around Nova Scotia/Maine has warmed > 1-2C in this time period. To see if maybe the BOGUs are wintering farther > north on the east coast, I looked at CBC data from Maine and indeed there > is a significant increase in BOGUs for their CBCs which matches the > declines that Shai showed. I couldn't get the Nova Scotia data to work for > some reason. I also looked farther south and in NC, for instance, there > also has been significant increases in CBC data for BOGUs too. So the > decline at least around LI and maybe even around Niagara Fall's probably is > related to the warming climate. Birds are shifting their wintering ranges > farther north. In the Great Lakes area, if the waters remain open farther > north some birds just don't make it down. The same is for the northeast > coast. In NC, I don't have much of an answer other than the sea surface > temperatures haven't warmed as much there. > > > > > > > > > On Wed, Oct 14, 2020 at 10:14 AM <rc...@nyc.rr.com> wrote: > >> Willie, that is very interesting. I had a quick look at CBC results - for >> NJ rather than NY, so as to avoid including any "Niagara Falls >> concentration effect," and the recent trend does appear to be a decline >> (with a few ‘exception’ years mixed in). In this graph "120" is 2019, and >> numbers extend back to turn of century. I know "birds per party hour" is a >> rough measure (I was a CBC compiler for > 25 years, potential party-hour >> reporting vagaries acknowledged), but the numbers do suggest either a >> decline in population or a shift in wintering behavior. >> >> Sorry, this was a quick take, now back to the ol’ day job… >> >> Rick >> >> P.S. Hope the attached graph comes through - if now (and you're >> interested) I can send on the side. >> >> -----Original Message----- >> From: bounce-125036389-3714...@list.cornell.edu < >> bounce-125036389-3714...@list.cornell.edu> On Behalf Of Willie D'Anna >> Sent: Wednesday, October 14, 2020 9:34 AM >> To: '& [NYSBIRDS]' <nysbird...@list.cornell.edu> >> Subject: RE:[nysbirds-l] Bonaparte's Gulls >> >> I have enjoyed the recent posts about Bonaparte's Gulls. Some of the >> highest concentrations of Bonaparte's Gulls in the world occur along the >> Niagara River, with estimates of 50,000 to 100,000 on some days. It is a >> spectacle to witness this blizzard of gulls on the Niagara but it seems >> that numbers have declined, particularly in the last ten to 20 years. It is >> unfortunate that the only evidence that I can offer for this are my own >> subjective observations. Counts of gulls on the Niagara have been done >> sporadically and it is only in recent years that organized counts have been >> conducted on a yearly basis, with three counts per season (late >> fall/winter), by the Canadian Wildlife Service. >> >> Numbers of Bonies, as they are affectionately called here, month to month >> along the Niagara, are highly interesting. Twenty to fifty years ago, >> numbers would begin to build on the Niagara in late July with most of these >> birds consisting of one-year-olds. By mid August, there would be a >> significant influx of adults, only just finished with their breeding >> activities in Canada. Hundreds of individuals could be seen at the source >> of the river (Buffalo/Fort Erie) and below the falls or in the >> Lewiston/Queenston area. At times there would be well over a thousand, >> particularly when there was a good southwesterly blow that would push more >> of them to the eastern end of Lake Erie. These numbers more or less >> continued, perhaps with a slight decrease, into October, although whenever >> there was a southwesterly blow numbers would spike considerably. The big >> numbers would arrive in late October/early November and reach their highest >> levels later in November. Numbers would then slowly decrease into January >> when at some point, ice formation would cause most of them to depart. >> During some milder winters, several hundred would remain through the >> season. In a typical winter, only a handful would remain. Starting in >> February, numbers would slowly start to increase and by late March they >> would be abundant again. Numbers would dwindle during April and they would >> be completely gone by about the third week of May, save for a variable >> number of non-breeding birds. June and July have been the nadir of the >> Bonies occurrence on the Niagara, although there were usually some >> immatures around, particularly on Lake Erie. >> >> To me, the most dramatic change with the Bonies here has been the numbers >> during spring. Whereas their spring numbers used to be very comparable to >> those during late fall, there have been some springs recently where peak >> numbers were barely into the hundreds, as opposed to the multi-thousands we >> were accustomed to. August through October numbers are also much lower >> these days, with counts of over 100 usually only occurring now when there >> is a bog blow off of Lake Erie. Peak numbers now seem to occur later than >> in the past, in December rather than November. >> >> One change that birders have enjoyed is that numbers of wintering birds >> are seen more consistently now, likely due to our warming climate. >> >> The Bonies are one reason that the Niagara River has been designated an >> important bird area (IBA). It is obvious that the Niagara River has played >> an important part in the life cycle of a significant proportion of the >> species numbers since the 1960s. Whether or not that will continue remains >> to be seen. >> >> Good birding! >> Willie >> >> >> >> >> >> -- >> >> NYSbirds-L List Info: >> http://www.NortheastBirding.com/NYSbirdsWELCOME.htm >> http://www.NortheastBirding.com/NYSbirdsRULES.htm >> http://www.NortheastBirding.com/NYSbirdsSubscribeConfigurationLeave.htm >> >> ARCHIVES: >> 1) http://www.mail-archive.com/nysbirds-l@cornell.edu/maillist.html >> 2) http://www.surfbirds.com/birdingmail/Group/NYSBirds-L >> 3) http://birding.aba.org/maillist/NY01 >> >> Please submit your observations to eBird: >> http://ebird.org/content/ebird/ >> >> -- >> >> >> -- >> >> NYSbirds-L List Info: >> http://www.NortheastBirding.com/NYSbirdsWELCOME.htm >> http://www.NortheastBirding.com/NYSbirdsRULES.htm >> http://www.NortheastBirding.com/NYSbirdsSubscribeConfigurationLeave.htm >> >> ARCHIVES: >> 1) http://www.mail-archive.com/nysbirds-l@cornell.edu/maillist.html >> 2) http://www.surfbirds.com/birdingmail/Group/NYSBirds-L >> 3) http://birding.aba.org/maillist/NY01 >> >> Please submit your observations to eBird: >> http://ebird.org/content/ebird/ >> >> -- > > -- Richard R. Veit Professor, Biology CSI/CUNY 2800 Victory Boulevard Staten Island, NY 10314 718-982-4144 fax 718-982-3852 -- NYSbirds-L List Info: http://www.NortheastBirding.com/NYSbirdsWELCOME.htm http://www.NortheastBirding.com/NYSbirdsRULES.htm http://www.NortheastBirding.com/NYSbirdsSubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/nysbirds-l@cornell.edu/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/NYSBirds-L 3) http://birding.aba.org/maillist/NY01 Please submit your observations to eBird: http://ebird.org/content/ebird/ --
