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/ --
