By Sue Leaf
Tucked away in a small cove of South Lindstrom Lake, a pair of Green Herons were making a fuss. They sat high in a dead tree. Their forms were dark, but I knew their bodies would be a deep green with a rich rusty-colored neck. The birds were hunched, like little pack-toting voyageurs. There was no mistaking their bright orange legs.
I often see Green Herons flying overhead, and before I can run through a list of possibilities, I hear a “Squawk!” uttered on the wing. Clearly, a Green Heron.
Green Herons are the second-smallest of all herons and egrets in North America. Only the Least Bittern is smaller. Unlike their Great Blue Heron cousins, they tend to be solitary nesters. A pair will co-operatively build a nest of sticks high in a tree, 5-30 feet up. Resembling a crow’s nest, it is more loosely built. T. S. Roberts reports that standing underneath, one can often see the pale green eggs laying within. Because the nests are secluded and the birds widely dispersed, it is hard to get a handle on their population size, but researchers know it is declining. In fact, the Breeding Bird Survey reports a 1.3% decline in the period 1966-2019, landing Green Herons on the list of Common Birds in Steep Decline.
The Chisago Lakes with its myriad wetlands is a good place for Green Herons. Their nest sites are selected near water, and they forage on the shoreline (less often in the water) for small fish of all kinds, insects, snails and even rodents. They are “sit-and-wait predators” following a prey with their eyes, then lunging suddenly to snap it up, or spear it, with its sizable beak. The little herons have been known to use tools—they will drop a feather or small stick on the water. When a fish comes up to investigate, wham!
The Green Heron has been expanding its range northward in Minnesota. In The Birds of Minnesota published in 1932, Roberts knew of no Green Heron records north of Pine or Sherburne Counties. A 1919 sighting of a nest along the St. Croix River in Pine County was the farthest northern nest. By 1987, birder Bob Janssen documented a continued northern expansion with nests recorded in southern St. Louis County. Even so, Tony Hertzel and Bob Janssen identified 27 counties—less than half—had documented nests in 1998, mostly in the south and central part of the state.
Using data from the Minnesota Breeding Bird Atlas, a state-wide land suitability model for Green Herons predicted the most suitable habitat would be in east-central Minnesota north to the southern edges of the extensive forests of the north. That lands the little heron on our doorstep, ours to protect from habitat destruction and loss due to development. And ours to enjoy when you hear a “Squawk!” overhead.
All photos provided by Gary Noren.
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