A good year for snowy plovers

11/07/2013

Western snowy plovers had a banner year in Point Reyes National Seashore in 2013, with 15 fledglings recorded by the end of the summer, the largest number counted since 2007. Wildlife ecologist Dave Press said changes to wire fencing, including the decision to not place cages around some nests—shallow “scrapes” in the sand that the birds line with shells—might have contributed to the success. The federally threatened wader named for its milky white belly has had a struggling presence at Point Reyes in recent decades and has been the subject of a restoration project in partnership with Point Blue Conservation Science since 1995. Biologists suspect the depredation of habitat, namely the expansion of invasive dune grass, may have diminished the appeal of nesting in the seashore. Predators like foxes and skunks hide in tall grasses and accounted for the loss of several nests this year; the circular cages used to protect nests, known as exclosures, can also inadvertently serve to attract those predators. Mr. Press said strong and sustained winds may also have buried some nests this year, though other sources of failure remain a mystery. This year’s mix of “more liberal” fencing and exclosures worked well, however: of 21 nests built between Kehoe Trail and the North Beach parking lot, 11 resulted in hatched eggs. Of 30 chicks, half lived long enough to fly away. Just where the plovers go is also unknown; Mr. Press said some overwinter at Point Reyes (there were 100 or so at Limantour last winter), while some migrate to warmer climates. The Fish and Wildlife Service has given the seashore a goal of 64 breeding birds, a steep climb from this year’s 18. A tagging project that will start in 2015 could help Mr. Press and his team understand just what limits the plover population—and how much control over it they have.