Andrew Keaveney's note re the recently sighted hybrid Lesser x Ross's Goose in Ottawa is an alert not only for that individual but for all small white geese. When I looked at the picture posted of that bird, my first thought was that it was almost certainly a hybrid. I have seen 5 hybrid geese in Eastern Ontario since 2013, including two yesterday. They were mostly adults. But I've only seen 2 Ross's Geese. While that is just my personal experience it does send a message that one must exercise caution when trying to identify these smaller birds.
My observation: At first glance they appear to be Ross's based on size but they are a bit larger if side by side comparison with Ross's is possible and I have had that good fortune on two occasions. I have also photographed them so I have been able to check in detail after the fact. The head profile is more like a Lesser Snow Goose than that of a Ross's which is clearly seen if you get a good look at the bird, but the bill is noticeably smaller than a Snow Goose yet larger than Ross's. Of course the bird is also smaller than a Lesser Snow Goose which is the subspecies seen in Southern Ontario. The important point is that birders need to know that this third alternative even exists and most don't. While Ross's sightings in the east have increased over the years and will likely continue to do so, the number of hybrids being seen in the east will at least keep pace with the pure Ross's we see in migration. The population of Lesser Snow Geese in the eastern Arctic has increased in the last few years to the point where we are now seeing pure flocks of thousands in spring migration after the main migration of Greater Snow Geese. While I don't know how the Ross's population is doing there (this is a western species for the most part), the opportunity for hybridization is increasing so this challenge will not diminish over time. A final note. The Ottawa bird was a juvenile hybrid between a Ross's Goose and a white Lesser Snow Goose. One of the birds I saw yesterday was a hybrid involving a dark morph Lesser Snow Goose. Dark morphs are a significant percentage of the Lesser Snow Goose population compared with Greater Snow Geese so observers in Eastern Ontario should also be checking for small mostly dark juvenile hybrids mixed in with Snow Goose flocks. Brian Morin Cornwall _______________________________________________ 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
