I had trouble identifying this bird in P.E.I., so called on my 'go-to-guy' and King City neighbour, Gerry Binsfeld, who identified it as a Common Yellowthroat. It appears to be an immature female, hence the pale yellow on only the throat.
Here's a Ruby-throated 'hummer' at my sister's house in Prince Edward Island.
Young Cliff Swallows look out over the Gulf of St. Lawrence
Please comment if you wish.