On a recent trip to Canada I was lucky enough to bird the Leslie Street Spit in Toronto for an afternoon - a great place, even in July!
I saw two Empidonax sp. which looked and called the same and managed to get photographs of one of them. I think it might be a Willow Flycatcher based on the long primary projection, poorly defined eye-ring and the call which was of the "whit" variety (described in more detail at the folowing link).
Any opinions would be much appreciated. The photographs can be seen here: