Posted by David Sparks on July 31, 2009 at 5:38 PM
In Lia's post about puzzling behavior in Skimmers, I stated that I had read that nestlings lack the asymmetrical bill of adults. In June and July, Least Terns and Black Skimmers were nesting in a protected area at one of the local National Seashore parks and I had a chance to verify this statement.
This chick was not close to the boundary of the protected area and the image has been cropped to about 50% of full frame. Note: 1) that the upper and lower mandibles are about the same length, and 2) the small yellow "twig" jutting out between the mandibles. This is the tail of a large (for the chick) fish that took the chick about 30 minutes to swallow.
Photo taken July 14, 2009 at the Ft. McRae National Park with a D300, my new 500mm f/4 VR lens + 1.7x tc and tripod.
ISO 800, f/8, 1/400 sec
Posted by David Sparks on July 31, 2009 at 5:40 PM
A photo of an adult is shown for comparison. Taken the same day but the adult was outside the protected area and I was able to get closer. Full frame image.
D300, 500mm f/4 VR + 1.7x tc, tripod
ISO 800, f/8, 1/160 sec
Posted by David Sparks on July 31, 2009 at 5:42 PM
This is a photo of the fish the chick had swallowed. Cropped to about 55% of full frame.
A nice photo series, David. BNA reports, "At hatching, the 2 mandibles are equal in length, but by fledging at 4 wk, the lower mandible is already nearly 1 cm longer than the upper." When I first saw Black Skimmers (Texas, 1998), I was fascinated and did some research. The asymmetric bill is only one of a number of specialized adaptations to their foraging style. Marvelous birds.
Posted by Mia McPherson on August 1, 2009 at 3:30 PM
David
I have always found the bills of Skimmers fascinating as welll as the mechanics of the act of skimming. These images are a wonderful example of how the bill changes from juvenile to adult. Also great behavior in the chick with the fish!
Discussion
5 repliesThis chick was not close to the boundary of the protected area and the image has been cropped to about 50% of full frame. Note: 1) that the upper and lower mandibles are about the same length, and 2) the small yellow "twig" jutting out between the mandibles. This is the tail of a large (for the chick) fish that took the chick about 30 minutes to swallow.
Photo taken July 14, 2009 at the Ft. McRae National Park with a D300, my new 500mm f/4 VR lens + 1.7x tc and tripod.
ISO 800, f/8, 1/400 sec
D300, 500mm f/4 VR + 1.7x tc, tripod
ISO 800, f/8, 1/160 sec
I have always found the bills of Skimmers fascinating as welll as the mechanics of the act of skimming. These images are a wonderful example of how the bill changes from juvenile to adult. Also great behavior in the chick with the fish!