December 24, 2017
Skagit River Delta, Pacific Northwest
The birds are active on the Delta flats right now, and not just the Snow geese. The other day when we stopped at our usual observation site on the dike, a couple of Great Blue herons were interacting in a way that showed off their beautiful plumage and distinctive language.
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The title photo was through the car window as we drove out, nice and close. I watched a territorial interaction a few minutes earlier from up on the dike that separates Skagit Bay from the agricultural fields of the delta. At this time of year it’s all about fighting over hunting territory, although “fighting” is not what we humans usually think of when we hear that term. Wild animals often just display their assets, demonstrating superiority, without actually coming to blows, and the lesser individual accepts it and backs off. That’s what these two were doing.
While I was standing up on the dike watching shorebirds, a heron swooped past me toward a drainage canal aka ditch. It landed next to another heron standing by the ditch and chased it across to the other side.
They were most likely both adult males:
On the Fraser River Delta in British Columbia, adult females and juveniles feed nonterritorially on beaches, estuarine marshes, and in fields in winter, while adult males defend year-round feeding territories (Butler 1991). (Birds of North America birdsna.org/...)
GBHs have an impressively expressive language, most of it nonverbal. This article (www.heronconservation.org/...) describes more than 100 different behaviors, each of which has specific meaning to other herons. What I saw on this occasion is called the “Upright and Spread Wing display”, in which one heron is threatening another that has strayed into its foraging territory. Usually this display and stalking is enough, though the situation may develop into a more physical attack.
Herons hold their bill straight up vertically also during courtship display (called the Stretch) but they don’t spread their wings out during that.
If the message isn’t made clear and resolved with this display, a physical altercation would be next. The bill is pointed horizontally, and they go at it (in what’s called Full Forward). Fortunately it didn’t come to that.
The other heron flew off, and the apparent “owner” of this ditch area folded up his wings.
GBHs are pretty solitary birds outside breeding season, and don’t ever seem happy being at close quarters with other herons. It’s nice to know they have ways of resolving differences without somebody getting hurt.
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Wet and mild in the Pacific Northwest today. Windy. Typical December weather.
What’s up in nature in your neighborhood?
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