When I go visiting relatives in Cornwall, I usually go to Cooper's Marsh in Lancaster (just 10 min east of Cornwall) and the Upper Nicholson's Locks near Kemptville.
There's usually a mix of everything at Cooper's, but there's usually at least 6 very visible Green Herons, we also had lots of swamp sparrows, flying and perching snipe, marsh wrens, Baltimore Orioles etc.
At upper Nicholson's, there's an active Osprey nest right beside the road, with lots of nesting birds right by the road.
