Thanks for this post. Out of curiosity, I did some quick looking into how possible it is for a roadrunner to show up in Ontario, and unfortunately it looks very, very unlikely -- and completely unprecedented, actually.
Firstly, if I were to guess as-to what was actually seen, I'd say its more likely that if it isn't a Ring-necked Pheasant, it's most likely some form of escapee domestic pheasant -- there are plenty of kinds of those around that looks different. Another possibility would be to look at other similarly-sized birds, and consider "what if" something went wrong with that bird's wings so it kept itself grounded.
Roadrunners are really interesting and unique birds, and unfortunately one of the things that makes them unique is that they have never been (officially, at least) observed outside of their natural boundaries. All kinds of birds show up as vagrants in all kinds of crazy places due to the fact that most birds, well, fly. They get caught up in weather systems, take a wrong turn at Albuquerque, etc. But roadrunners are not only non-migratory, but they only have been noted to fly when escaping a predator. So, if an oddball "migratory" roadrunner were to exist, it'd be doing it by foot.
A quick check on eBird, no recognized records of Greater Roadrunners exist anywhere closer to Ontario than 200 miles southwest of St. Louis. No records at all anywhere in Canada. Also, no records at all anywhere but the US/Mexico. Lesser Roadrunners have never been seen north of Mexico, no recognized records in the US.
A possibility is an escaped domestic roadrunner, but there's good reason to doubt this too. Specifically, it is highly illegal in the US to own a roadrunner of any kind as a pet, so if this was the case then it would have been smuggled into the country, or purchased on a black market of some sort for great amounts of money... only to then escape.
An interesting fact I did not know before looking into this: roadrunners are technically cuckoos. Maybe it was an oversized cuckoo?
In any case, it was fun to take a look into how possible it is for a roadrunner to show up here. Too bad it seems so unlikely.
