Heron Sunning Postures aka Flasher Pose

Great Blue Heron Sunning along the St. Johns River

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The first time I saw a bird standing with its wings spread, wing tips drooped down, and its belly feathers puffed out I was sure it was looking for a mate! I remember thinking it was so unusual that I looked around me to see if anyone else was there to witness this rare event. I knew nothing of heron mating displays but those files were henceforth given file names like ‘Great White Heron-Flasher Pose!’ Seeing this magnificent subject of fine art paintings in such an indelicate stance was a revelation to a newbie bird watcher.

Accustomed to seeing Anhingas and Cormorants standing on marine pilings with their wings spread in the sun drying their feathers, it was just unexpected to see the posture in a great heron. Spread-wing postures seem to serve different purposes in different species and it is seen in pelicans, storks, herons, vultures, hawks and even small songbirds which puff out their belly feathers with wings extended.

For example, Turkey Vultures employ the posture for both thermoregulation and drying. Their body temperature is maintained at a lower level at night than during the day. Morning wing-spread behavior is a means of absorbing solar energy and passively raising their temperature to proper daytime levels.

Anhingas have rather low metabolic rates along with high rates of heat loss from their bodies. Wet or dry, they display spread-wing postures when there is bright sunlight and cool ambient temperatures. Generally they orient themselves with their backs to the sun to offset the heat loss. Since their plumage is wettable but not water-repellent this dries the feathers and is also thought to realign the feathers and to force parasites into motion for easier removal.  Cormorants, on the other hand, use spread-wing postures only for drying their wings and not for thermoregulation. Only the outer portion of the Cormorant feathers is wettable, so they maintain an insulating layer of air next to the skin when swimming underwater.

The observed Flasher Pose in the herons is one of their maintenance behaviors. I have never seen this pose in a heron that it was not facing the sun. The sunning or wing drying stance does not appear to be strictly  for thermoregulation or drying in the herons. In fact many times when I’ve seen herons do this they exhibit cooling behaviours such as rapid breathing with the mouth open and vibration of the throat at the same time as they are wing-spread facing the sun. So it seems logical that the bird keeps itself cool while setting up a hostile temperature for the parasites or other pests. Once on the move the bugs are more accessible and easier to remove during preening.

Even with detailed observations recorded in volumes of ornithological research down the ages, it seems many observations are couched in words like seems or apparently or thought to be. We will always be looking for reasons in the realm of instinctual behaviour. It could very well be that herons sun themselves because it feels good. How do you measure mood in a bird?

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 Great Blue Heron Sunning along the Indian River in Merritt Island

Oh Baby!!

Night Heron  “Flasher Pose”  🙂

 This was the Great White Heron I first saw in the wing-spread sunning stance. It looks beautiful no matter what pose it assumes.

Great White Heron in a private mangrove setting sunning. You can see how puffed out the belly feathers are into almose a column like shape.

 Closer up front view of the sunning posture reported to aid the bird in ridding itself of parasites. The solar heat put the parasites in motion for easier removal during preening. The Great White Herons are often seen with ticks in the feathers.

 I was so impressed with the new found pose that I moved all around for various angles even though at the time I felt I was intruding on private seclusion.

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Thanks,

Judy

Source Credits:

Heron Conservation – with behaviors terminology pdf

Stanford Essays

~ by Judy on April 7, 2013.