09 July 2015

Plovers and Terns Thrive on Flood-created Sandbars

Sandbar habitat from the "great flood" have been providing a safe haven in 2015 for terns and plovers as an increased amount of water is being released from Gavins Point dam.

"Water levels in 2015 have caused no issues for these birds," said Douglas Latka, a biologist with the U.S. Army Corps of Engineers office in Omaha. Both the Least Tern and Piping Plover have been using sandbar habitat with an elevated height well above the measured flow levels in the Missouri River below the dam.

A notable increase in the extent of water released from the dam at Gavins Point occurred in early July. The higher water level has not been detrimental to the terns and plovers, as the fledglings utilize sandbar habitat that is not inundated by river water.

Habitat conditions along the Missouri National Recreation River this nesting season and in the previous few years, make management much easier, said Latka.

Sandbars used as nesting sites this year are a result of the "great flood" of 2011 when an extensive amount of sediment was deposited, increasing the availability of sandbars with an elevation notably above the river flow, Latka said. Nesting plover and terns have not needed to utilize less than optimum habitat, such as sites that might have been prone to being flooded by higher water releases.

Details on nesting activities for 2015 indicate there were fifteen nesting localities for the Least Tern, and of the 181 nests, at least 41 were successful, and 77 chicks were observed by the research team managed by the Corps. Of the 184 Piping Plover, 105 nests were observed to be successful, with 257 chicks observed.

"These are the boom years," for both species, Latka proclaimed, since ample high-quality habitat has been available. Annual vegetative management efforts have also helped to clear areas where plants might have otherwise encroached to an extent that the site would not be conducive for these ground nesting birds.

After nearly three decades of studies, "we understand the variables between habitat management and water flows during the breeding success," said Latka, This helps ensure that any actions minimize any unwanted "take" of birds.

The Corps has been monitoring populations of both species along the Missouri River since 1986.

Increased releases of water from Gavins Point dam this season have occurred to accommodate a barge which is transporting building materials for a fertilizer plant at Sioux City, Latka said. A second reason has been to achieve a flood level target for Kansas City, which has had a significant influence on river flows this year.