Comet Darners are historically very rare in Ontario, typically being found only to our south. In fact, when the current Ontario Odonata Atlas species maps were done up in the early 2000s the map for Comet Darner had only 2 records on it! However, in the last several years we have seen an increasing number of records, still all from southern Ontario where migrants are more expected. It is hard to know for sure whether the increase in records is real or just an artifact of the greatly increased search effort by the growing number of dragonfly enthusiasts in Ontario. Realistically, it is probably a combination of those two factors.
The Brantford record is especially intriguing because Bill also found Comet Darner at this location last year, which may suggest that the species successfully overwintered at the site - something that hasn't been demonstrated yet for Ontario. We did a quick search of the shoreline for exuviae but were unsuccessful in finding any. Of course, with the abundance of other migrant species at the site, maybe it is just the perfect spot for migrant species to drop in to...
This species is similar to the familiar Common Green Darner, but the red abdomen is really distinct. Another easy field mark is the patterning of the postfrons (think of it as the top of the 'nose') - on Common Green Darner there is a "bulls-eye" pattern, while Comet Darner is plain:
|Top view of head and postfrons of Comet Darner|
|Top view of head and postfrons of Common Green Darner|