23 July 2009

Barge Nesting Terns - Continuing Success at Riverlands

Least Terns nesting on two barges have been having continued success in nesting and raising young atop an artificial island in the Mississippi River at the Riverlands Migratory Bird Sanctuary.

"In this photo you see the interesting placement of the nest, on left between two logs and so close to the pair of decoys. 7 July 2009. Photo by U.S. Army Corps of Engineers - Rivers Project Office" — website caption

"Barges were pushed into place and anchored on April 30, 2009. First reported sighting of Least Terns in the area and landing on the barge was May 14, 2009. On June 19, 2009 confirmed one nest on the floating habitat with three eggs with a short visit to the barges." — project FAQ, provided by the Army Corps of Engineers, the managers of the project area
"The project consists of two floating pontoon barges anchored in Ellis Bay (no wake area), Mississippi River Mile 201.7. The two barges are lashed together for a combined 1,500 ft2 of temporary nesting habitat. These barges are topped with approximately 5” of a sand/gravel mix, to simulate a sandbar habitat. Timbers (6’x6’) are used to edge the barges, so the sand/gravel mix will stay on barges, but allow rain water to drain off. Conspecific attraction equipment (call boxes and decoys) are also used on the barges in an attempt to interest the birds in this particular site. There are a total of 20 decoys located on the barges; most of them are in pairs. The call box recordings run intermittently for 24hours. The main power source for the call boxes is a marine battery, which is connected to a solar panel to maintain a full charge. The call box will be stopped if and when the Least Tern eggs hatch."

The Illinois Department of Natural Resources and Illinois Natural History Survey have "provided technical expertise on barge placement, call box and decoy set-up, and may conduct studies if successful breeding occurs."

Regular Web Updates and Photos

Regular updates - with the Least Terns most recently watched chasing away pesky crows - are showing the saga of these endangered birds at the 2009 Endangered Interior Least Tern Nesting Barge Project website.

July 15
..."Second-2 American crows did try to attack the tern island (I am almost positive they were crows, however while I don't wish for another attack to occur, I would like confirmation if anyone else sees the same). For about 5 minutes these two crows would repeatedly fly around the barge and swoop in. While I did not see the crows actually take a chick or egg, I cannot say with confidence that they didn't either. There was so much going on between the terns attacking, the crows swooping, and I was trying to keep an eye on the chicks, that I might have missed something. ... Plans are underway to add more debris for cover out there." — Vincent Giammaria, NGRECC Intern, A.C.E.; graduate student
July 11
"20+ adults - difficult to count for sure. ... 2 chicks out in the open - front corner of the barge nearest to Ellis Island- being attended to and guarded from other approaching LETEs" — Charlene Malone
July 9
"About two years ago, corps biologists were approached by a graduate student from the University of Illinois who wanted to use con-specific attraction equipment to coax least terns into nesting. — article in the Kansas City Telegraph
July 6
As of today (July 6) the count is up to between 15-18 from what I could see...although I don't have eyes in the back of my head (nor on the sides) to watch the barge, Heron Pond, and the numerous mud-flats in the area at the same time. My best estimate is from when the entire population took flight at once over the barge airspace where I counted 15 for sure, and then lost track as numerous terns changed course direction and what not. My other best estimate came from a count of 7 on a nearby flat and 10 on the barge at the same time. So my guess is between 15-18, but there is likely more either off foraging in the distance, or just hidden from view on the barges. ... As far as nesting goes, I still think there is likely 3-4 with 1 confirmed." — Vincent Giammaria, intern with the National Great Rivers Research and Education Center

The efforts of the terns are closely chronicled, with numerous pictures of the nesting barge and the activities of the terns.

The Rivers Office had tried creating a sandy island nesting site in 2002, but the birds did not use the site.

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