All, I know some of you might sigh and think, ''here we go again'', but - fear not - I am not the voice of doom this time!
Intrigued by the spat of recent and less recent Bewick's Swan records from Ontario, I thought I would do a bit of poking around, just to see if the origin of these birds can be ascertained, or at least given some sort of probability. I contacted Glen Howe, an Ontario waterfowler with a large, varied collection who also has deep contacts with other waterfowler's across the continent. Glen's assessment of Bewick's Swan in captivity, both regionally and throughout North America was ''rare as hen's teeth,'' as the species is expensive and complex to import and is a very poor breeder in a captive setting. He felt that likely two or three breeders total might still have some in their collections. This assessment is also borne out in IWWA [International Wild Waterfowl Association] data, found in the form of two surveys of members collections. You can see that the 2010 survey found only 6 birds reported anywhere. http://www.wildwaterfowl.org/captive-waterfowl-survey.html For sure, these surveys need to be taken with due consideration, as the numbers of almost all species is very low and likely represents only a fraction of the true number [due to non reporting] but they can be used as a general indicator. I'm sure many would say that the origin of any Ontario Bewick's Swan wasn't suspect in the 1st place and that's a fair enough point - especially since there are numerous records from the Pacific coast, as well as a documented record from 2007 / Regina SK, of a family group of four - two adults and two imms....pretty compelling. I know the 2013 Ridgetown Bewick's was accepted by the OBRC and I would assume they used many of the same sources of information that I have in coming to that decision, although I still think its fine to be a bit circumspect with any species that might come from a collection. On top of that, this species, while seemingly regular along the Pacific, has almost no records from the Atlantic [perhaps as expected, as source would likely be Eurasian] but with almost no records between either coast as well, apart from states adjacent to the Pacific, then declining rapidly eastward. [source ebird - and, yes, I fully understand the limitations of this data!! I have not done an exhaustive search so treat the above as cursory] Another take-way from the IWWA surveys is [proportionally] species like Smew, Baikal Teal, Tufted Duck and Falcated Duck are common captive species. This jives with my experience speaking with Ross Snider and some of his colleagues here in Ontario. I really don't want to get into another debate about probability and statistics on any of the these species, I'll just say origin for some records should be assessed based on what we know about captive populations. I think the general consensus on birds like Falcated Duck and Baikal Teal is default escapee's, which sounds suitably prudent to me. Finally, one thing that both Glen and Ross have mentioned in the past is the high cost of keeping exotic waterfowl. This cost goes up when the value of the birds declines and this pattern mirrors the pattern of the general business cycle and stock market. So, in periods of market declines, some waterfowlers may ''dump'' some of their collections when prices crash and costs soar. I'm not sure it could be borne out statistically but might be something to keep in mind while birding during the next 'great recession'.....;] Cheers, James Holdsworth, Biological Consulting Services 14 Marian St, RR#1 Woodstock, [email protected] 'If one does not fail at times, then one has not challenged himself.'' - Ferdinand Porsche _______________________________________________ ONTBIRDS is presented by the Ontario Field Ornithologists - the provincial birding organization. Send bird reports to [email protected] For information about ONTBIRDS including how to unsubscribe visit http://www.ofo.ca/site/page/view/information.ontbirdssetup Posting guidelines can be found at http://www.ofo.ca/site/page/view/information.ontbirdsguide
