The Nature
Observer’s Journal
The Nature
Observer’s Journal
Decurved, Reflected and Refracted:
Images of White Ibis at Work
Chuck Tague
It was a little before noon and I was alone in Centennial Park in Holly Hill, Florida. Maybe not alone but there were no other people. I sat in the picnic shelter and watched the eagles’ nest. Bald Eagles in Florida breed on a different schedule than those in the north. The male brought in a fish but there was none of the usual excitement. The eaglets must have been well fed. The parents just hung around -- what eagles do best.
A group of wading birds on the edge of the small lake decided I wasn’t a threat and foraged along the water’s edge in front of me. There were two adult White Ibises, two ibises in their first winter and a Little Blue Heron. The young ibises were conspicuous with their brown wings, back and tail and a scaly gray head and neck. Obviously the waders were used to people in the park. Possibly they instinctively knew that eagles, a real threat, avoided people.
Caution -- Waders Crossing
White Ibises are the most gregarious of North America’s waders and I was surprised to see only four. I guessed they were a breeding pair with last year’s offspring. The lethargic eagles soon bored me; I turned my attention to the feeding behavior of the young ibises.
Ibis are mostly tactile feeders -- they hunt fish and aquatic invertebrates with their touch-sensitive beak. Long and decurved to probe in mud, under debris or among vegetation, the tip of an Ibis’ beak is well innervated (contains many nerve endings).
Their head projects at a peculiar angle so their bright-blue eyes can see down their beak as they feed. The advantage of the eye color is a mystery to me; possibly, like the cormorant’s blue eyes, it helps the ibis see through glare on the water’s surface.
The two young birds were more curious than hungry. They picked up strips of floating paper, pieces of wood and other inedible items. Each piece was carefully twirled and bounced between the sensitive beak tips before it was rejected. One ibis placed a piece of paper near the bank, then retrieved it when it floated away.
I moved carefully to the bank for better photos. I was pleased that I got so close to the birds without disturbing them. As usual, I was kidding myself. When I returned to the picnic shelter the four ibises climbed onto the bank, exactly where I set up my tripod, and probed in the grass. They continued feeding until they’d moved even closer to me.
View more images of the ibises in the Nature Observer Gallery.
Tuesday, February 21, 2012