Back in May of this year, I had the pleasure of photographing a magnificent Great Blue Heron at the Sequoyah National Wildlife Refuge in Oklahoma. This large wading bird was stealthily stalking the shoreline, patiently waiting to strike small bait fish with its long, spear-like beak. I was able to capture some incredible shots of it in action as it snapped up fish after fish.

Great Blue Heron's Red Eyes and Fresh Catch

Great Blue Heron’s Red Eyes and Fresh Catch

However, upon reviewing the images on my computer, I noticed something peculiar. In every single photo, the heron had distinctly red-tinted pupils! When I zoomed in closely, its eyes had a reddish hue unlike anything I’d ever seen before in a heron. The vibrancy of the red took me by surprise. At first, I thought it might be some odd lighting effect or camera artifact, but upon closer inspection, I confirmed that the color was real.

Great Blue Heron with Red Eyes and a Fish

Great Blue Heron with Red Eyes and a Fish

Intrigued by this discovery, I decided to conduct some research to find out what could be causing this unique eye coloration. However, despite my best efforts, I found no mention of red-eyed Great Blue Herons anywhere. I scoured ornithology resources and checked with other wildlife photographers, but no one had an explanation.

Great Blue Heron With A Red Pupil

Great Blue Heron With A Red Pupil

Today, I decided to give it one more try and stumbled upon a suggestion that the red coloration could be caused by an abundance of astaxanthin – a red carotenoid pigment – in the heron’s diet.

Astaxanthin is found naturally in the aquatic creatures that herons feed on, such as salmon, trout, algae, and crustaceans. The more of these red-hued foods they consume, the more astaxanthin is deposited into their feathers and tissues. It could be that this particular heron’s diet was rich in these pigment-producing foods, resulting in its vivid crimson eyes.

Note: While astaxanthin is found in the diet of some birds, such as flamingos, there is no evidence to suggest that the red color of a Great Blue Heron’s pupils is caused by an abundance of astaxanthin in their diet. Therefore, it is unlikely that astaxanthin is responsible for the red color of a Great Blue Heron’s pupils.

The workings of nature never cease to amaze me! I feel privileged to have witnessed such a rare sight and to have been able to capture it on camera. They say that the eyes are the windows to the soul, and this heron’s soulful red eyes will be etched in my memory forever. I’m just glad that I can now share the wonder of it with all of you. Let me know if you’ve ever seen something similar in your own wildlife adventures!

Image Information:

  • Date: 5/31/23
  • Time: 7:18 AM
  • Camera: Canon EOS R5
  • Lens: Canon RF 100-500 mm F4.5-7.1 L IS USM
  • ISO: 4000
  • Aperture: 8
  • Shutter: 1/2500
  • Exp. Comp.: +0.7
  • Lens (mm): 500
  • Program: Manual