Least Terns and Piping Plovers

Since 1991, Nebraska Public Power District has constructed and monitored habitat along the Platte River corridor for the interior least tern and piping plover, two birds on the federal threatened and endangered list.  An interim measure on the Federal Energy Regulatory Commission (FERC) license for NPPD’s Sutherland Project directed NPPD to construct riverine islands suitable for nesting islands in the central Platte River.  However, NPPD’s biologists observed that most of the least terns and piping plovers in the central Platte nested on piles of sand left over from the commercial gravel mining operations (sandpits) common in the area.  Under our own initiative NPPD undertook management of sandpits with known nesting to see if reproductive output could be improved.

Least terns and piping plovers both nest on barren sand and will abandon a site if vegetation occupies more than about 25% of the site.  Since 1991 NPPD has constructed and manages three nesting sites on Platte River islands.  NPPD also manages three nesting sites at sandpits – one near Lexington and two near Elm Creek.

From figures recently released by the District, it’s clear that the birds prefer to nest at the managed sandpits. “Managed” refers to a nesting habitat that has had work done “to optimize the potential for terns and plovers to produce nests and chicks,” said John Shadle, NPPD’s water resource advisor. Work at the sandpits and islands includes controlling vegetation and shaping beach surfaces, erecting fences to minimize predation and posting signs to keep people a safe distance from nesting areas.

Piping plovers arrive in Nebraska in mid-April and begin nesting in early May, then typically migrate back to their winter ground in mid to late July.  Piping plovers most commonly lay 4 eggs in a scrape in the sand lined with pebbles.

Least terns arrive in Nebraska in late May and begin nesting soon after with peak nesting being the first weak in June.  Least terns most commonly lay three eggs in a simple scrape in the sand.  Least terns can typically be found in Nebraska until late August.

To evaluate success, NPPD monitors the number of nests and number of fledglings for each species.  A fledgling is a young bird that has learned how to fly, typically by about 21 days of age.  As of the end of the 2005 nesting season, NPPD nesting sites have had 522 least tern nests and produced slightly more than 580 fledged least terns.  In addition the sites had 174 piping plover nests and produced 270 fledged piping plovers.  Over 90% of all fledged young for both least terns and piping plovers have come from the three sandpits.  From 1991 to 2003, the only documented production of fledged least terns and piping plovers in the central Platte River came from NPPD managed sites.