I wonder if BOGUs are wintering farther north due to recent milder winters?
On Wed, Oct 14, 2020 at 7:12 PM <[email protected]> wrote: > I’m most pleased at the developing discussion on small gulls and other > bird population fluctuations (mainly declines ☹). > > > > One quick thought – on choice of statistics (which several raised): when > dealing with crowd sourced data (yeah, that includes CBC, well-tended > though it is), it’s always apples and oranges to some degree. If the effect > is strong enough, it will carry through across a number of approaches (as > seems to be the case here, not insignificantly!). > > > > The best evidence for this discussion would be either (1) a Zeusian, > universal, longitudinal population census worldwide, or (if Zeus isn’t > around), a really accurate sampling census, based on sightings by a giant > number of random field groups, to determine likelihood. Neither such > precise dataset is readily at hand. So we have to squint at what we have, > augmented by rich, expertized field observations, which fortunately are in > at least adequate supply. > > > > As I said at the start of my post, I didn’t have much time this morning > and grabbed what I could find quickly. Very pleased to see additional info > others have posted (e.g., from CBCs where the data parameters are known > personally, and thus trustable, as w/Dick’s), or longitudinal counts from > Niagara (a world concentration point, with systematic censuses), or even > careful notes from Gravesend Bay (though movements here can be ephemeral – > but hey, it’s still information, and I like the place!). > > > > Hope folks keep grappling with how to best sort all of this stuff out. > Citizen science at its best should actively embrace these issues – even > though I actually kind of hate the term “citizen science” as it’s sort of > condescending and ambiguous, but probably that’s just me. > > > > Best to the list, > > Rick > > > > *From:* Richard Veit <[email protected]> > *Sent:* Wednesday, October 14, 2020 5:07 PM > *To:* [email protected] > *Cc:* Willie D'Anna <[email protected]>; & [NYSBIRDS] < > [email protected]>; Emily Peyton <[email protected]> > *Subject:* Re: [nysbirds-l] Bonaparte's Gulls > > > > here is a plot of bonaparte's gulls on massachusetts cbcs 1979-2018. All > the major coastal aggregation spots i know of (Campobello Is, maine, > Newburyport, MA, Provincetown and Nantucket, MA, Jones Inlet, NY, Staten > Island, NY) have dropped from thousands to tens of thousands of birds to > handfuls. We missed it on the Staten Island CBC this year and saw hardly > any at Nantucket. I used just total birds rather than birds per party hour > in the graph because the birds are all in one place and are either seen or > not seen, regardless of how many people or groups on the cbc (more or > less)........ > > > > On Wed, Oct 14, 2020 at 10:08 AM <[email protected]> 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 > > > > -----Original Message----- > From: [email protected] > <[email protected]> On Behalf Of Willie D'Anna > Sent: Wednesday, October 14, 2020 9:34 AM > To: '& [NYSBIRDS]' <[email protected]> > 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/[email protected]/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:* > Welcome and Basics <http://www.northeastbirding.com/NYSbirdsWELCOME.htm> > Rules and Information <http://www.northeastbirding.com/NYSbirdsRULES.htm> > Subscribe, Configuration and Leave > <http://www.northeastbirding.com/NYSbirdsSubscribeConfigurationLeave.htm> > *Archives:* > The Mail Archive > <http://www.mail-archive.com/[email protected]/maillist.html> > Surfbirds <http://www.surfbirds.com/birdingmail/Group/NYSBirds-L> > ABA <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/[email protected]/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/ --
