Saturday, July 7, 2012

Great Blue Herons at Rock Cut State Park - weird behavior?

Great Blue Herons wondering when the cooler temps will get here?
A pair of Great Blue Herons looking straight up in the air, Rock Cut State ark, Rockford, IL; 7/6/2012.
Yesterday, I decided to brave the 103 degree temperature and take the 4 1/2 mile hike around Pierce Lake at Rock Cut State Park.  Objective? To see what foolish people (other than myself) and wildlife would be out in mid afternoon on a day like this. Usually if I walk at a steady pace without stopping (pre-birding days) the hike would take no more than 90 minutes; however, since I have started taking wildlife photography, which then logically led me to take more interest in birds, which then turned me into a more active birder, the hike now takes me 3-4 hours. Yesterday's hike took me 3 hours.
So what are these Grt Bl Herons doing? Praying for rain? Pleading to the Nature Gods for temperature relief?
At the beginning of my hike at 3 PM, I noticed these two Great Blues standing near the shore looking straight up in the air like a Cormorant. When I saw their silhouettes, as they were back lit, my first reaction was, "Those are really large Cormorants," or "What are Anhingas doing here?" Of course, i knew they were herons, but in the few years of birding (only a 2-3 year novice), I have never seen Great Blue Herons do this.
Initially, what caused me to look their way was that I was following the flight of a Belted Kingfisher, which landed in a tree above where the herons were wading. So I thought that they were watching the Kingfisher. but even after the Kingfisher flew off, they continued this behavior. 
What's up there that's so interesting? Perhaps this a way of cooling off?
I would estimate that these herons were looking up for between 5-10 minutes, before I hiked a little too close for their comfort and they flew across the lake. I saw at least another half dozen Great Blues and one Green during the rest of my hike, and no other Herons were looking up in the air as this pair.

So if any readers have come across this behavior, let me know, and if you know why they were doing this, also clue me in. Thanks ahead of time.

Thanks to Barbara from the Illinois Ornithological Society (Link below) for her explanation of this behavior. See her comment below:

"That posture is a typical threat display. My guess would be that one heron was intruding on the feeding territory of the other and they had a "Mexican standoff" type of interaction going. Great Blue Herons aren't going to suffer from this kind of heat the way we do. Their range extends well into the steamiest parts of the tropics and they are in the water much of the time. Their plumage is not very thick. In fact, it always surprises me that we can almost always find them around here in the middle of winter."
Barbara Williams
IOS Membership Secretary
Winnebago Co.

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