Friday, August 8, 2008

Digiscoping in an Earthquake - 22 July 2008

Well, not exactly. But, trying to digiscope from a bridge with passing car and truck traffic is no less troublesome. On 22 July 2008 Greg Norwood (USFWS) from the Large Lakes Research Lab on Grosse Ile invited me to come down to the free bridge and photograph the Common Tern colony. So, I hauled my Nikon D300 and digiscoping gear and headed off toward the middle of the bridge.

It was warm and sunny and the terns were a bit upset with our presence. As Greg climbed to a higher level on the bridge to make nest counts, I stood on the catwalk, digiscoped and attempted to capture flying birds w/ the D300.
Digiscoping was difficult. The birds were quite cooperative, but traffic on the bridge made digiscoping next to impossible. Vibrations rattled the scope and optics so much that I felt like I was about to lose my lenses. So I had to focus, hold the shutter on the Coolpix P5000 half-way, and wait (sometimes for several minutes) for the traffic to clear just enough so that I could take several frames.

Flight shots were no easier. With birds flying at me with their angry clicking sounds, I was unable to focus fast enough to get sharp captures. After a few minutes, though, they settled down to feeding, flying, and squabbling amongst themselves for roosting positions. In all, I took over 2200 frames, and was delighted to have gotten almost 300 sharp keepers. Its taken me 'till now to process all the images and send them off to Greg, who hopefully can use them for good use.
Just a note about the colony. Greg has been studying the vegetation there and its effects on the colony robustness. Several different attempts and methods have been employed to protect the colony from predation by Black-crowned Night Herons, racoons, and mink*. The gravel/cobble/cement substrate under the bridge is less than ideal for nesting, and of the 60 or so nests found, most were failed. Eggs were found on cement platforms next to stacks of steel rebar and old chains, or in cracks between large cobble stones with no other material.

Still, there were some successful fledging of young. I managed several nice flight shots of juvenile terns and others in various forms of development.

It was a wonderful day for photographing the colony. Thanks Greg for the opportunity to witness a tiny spectacle!

* - This morning I received word that a mink den was found near the colony, so it may explain the predation problem....

Thanks for looking!

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