Green Herons at Pine River Fishing Sanctuary
On July 6-7, 2024, we had our first Earth Tracks Tracking Apprenticeship weekend for the 24-25. Our learning and explorations centred around the Orangeville area.
At two of our meeting sites, both near the Mono Amaranth Townline and at Pine River, we were greeted by the sight of green herons (Butorides virescens- translated meaning “greenish and bittern-like”) calling and flying past. At Pine River especially, we were able to observe the herons multiple times as they flew up and down the river.
The green heron is described in the National Geographic Society Field Guide to the Birds as a “small chunky heron with short legs, grey-green upper parts , chestnut brown head, neck and upper breast, and a paler brown belly”. It has a green-black cap with a small crest and a white throat. The bill is two-toned with a dark upper mandible and yellow lower. The legs are usually a dull yellow, but the during the height of breeding season, the legs of the male are a bright orange colour. We were able to see the bright colouration of the legs of at least one of the birds at Pine River.
Green herons winter as far south as Mexico.
I have been fortunate to have green herons nesting at a pond where I work, so thought this blog would be an excellent opportunity for me to learn more about this smaller cousin of the more commonly seen great blue heron (Ardea herodias).
For a full summer I mistook the flight call of the green heron for the chirp of river otters (Lontra canadensis). But once I was able to put the bird and their call together I began to notice them regularly and was able to identify the rough location of their nest.
In the summer of 2023, we were fortunate to have a young green heron leave their nest and land on a floating mat of moss and other plants in a spot where we were able to observe them for several days. I invited local photographer Thom Morrisey to come and snap some pictures.
Though I watched carefully on and off for three days, I never did see a parent feed this youngster and after a few days it appeared to have left. Eventually my curiosity got the better of me and I paddled out to get a closer look. The baby was still there, just further into the vegetation. It was spooked by us and it flew back to the area of its nest. It was very camouflaged until it flew.
While we were not able to locate the nest at Pine River, the frequency of our observation of the birds over the afternoon led us to believe that there was likely a nest on the opposite side of the river. This assumption was further validated when I found w
hat appeared to be part of a green heron eggshell in the forest where we were tracking.
According to Colin Harrison’s A Field Guide To The Nests, Eggs and Nestlings of North American Birds, green herons breed by water in many habitats including on tussocks or muskrat houses, and at varying heights in trees by both salt and fresh water. From my observations, they usually nest near moderate sized ponds around an acre or two in area. They usually use the same nest site over successive seasons. Their clutch size ranges from three to six eggs which range in colour from creamy to pale blue-green.
Green herons are opportunistic feeders, preferring small fish (iBird Canada). From my observations, these birds hunt from branches and trees overhanging the water more than blue herons, who most often wade with their necks extended.
The government of Canada reports that green herons have experienced moderate decline over the past several decades most likely due to the draining of wetlands and the pressure of increased urbanization. They are not a species of special concern at this time.
Apparently this bird can sometimes develop a tolerance to living near people. Unfortunately, the pair I have regularly observed did not return to our pond this summer. I hope it was not because of us.
The opportunity to watch the green herons at Pine River was gift for all of us. It was special to spend time tracking the shore of the river and observing this interesting species.
