Bird of the Month: Snowy Plover
Written by Andy McCormick
Andy McCormick, Volunteer and Former Board President of Eastside Audubon
Snowy Plover
Scientific Name: Charadrius nivosus
Length: 6.25”
Wingspan: 17”
Weight: 1.4 oz (40g)
AOU Alpha Code: SNPL
The well-camouflaged Snowy Plover blends into its sandy surroundings, but Washington’s small population needs ongoing protection.
CRYPTIC PLUMAGE FOR PROTECTION
While walking along the beach it is quite easy to miss seeing a Snowy Plover even in areas where they breed. Their backs are the color of the dry sand close to dunes and dry washes where they often sit motionless. Snowies are distinguished from other small plovers by their long, dark bill, gray legs, and the thin white collar that encircles their neck.
These plovers are classified in the genus Charadrius, from the Greek kharadrios, a bird found in river valleys or ravines, and, in Washington, in beach dunes (Holloway). The species name nivosus is from the Latin for snowy, or full of snow (Latdict). Video of Snowy Plovers can be seen at the Macaulay Library.
BREEDING IN THE SAND
A small population of about 50 Snowy Plovers breeds in southwest Washington at the northern limit of the species’ breeding range. The nest is a scrape in the sand near a small grass tuft, a piece of driftwood, or some rocks and shells. The three pale, buff-colored eggs are deposited directly onto the sand. Incubation by both parents lasts about a month and young will leave the nest a few hours after hatching feeding on their own. They can fly in another month (Kaufman).
Snowy Plovers have evolved a polyandrous breeding pattern. Sometimes a female will leave the nest a few days after laying eggs and seek another partner to establish a second brood. The male is left to tend to the first brood. After this first group of young fledge, the male may then also seek another mate to establish a second brood. With all this breeding activity one might think Snowy Plovers are producing enough young to maintain a stable population. However, these Pacific Coast plovers are declining. The nests are quite exposed and threatened.
ENDANGERED IN WASHINGTON
The North American population of Snowy Plovers totals about 18,000 individuals. These birds were designated Threatened by the U.S. Fish and Wildlife Service in March 1993, and the population in Washington has been designated Endangered by the Washington Department of Fish and Wildlife. The Washington population is now dependent on immigrants from Oregon to maintain its numbers.
Human activity leading to habitat loss or degradation in both breeding and wintering habitats is the primary threat to Snowy Plovers (Alderfer). However, increased predation from several sources adds to the threat. Common Ravens have expanded their range and feed on eggs and chicks. Coyotes and introduced nonnative red foxes are the chief mammalian predators. Storm surges and high tides will flood nests and drown chicks. People, vehicles, and pets will often crush or disturb nests and the plovers themselves. (Page, et al).
CONSERVATION AND MANAGEMENT
The Pacific Coast population of Snowy Plovers is treated as a single biological unit under the Endangered Species Act and has a recovery goal of 3,000 birds. Combined breeding season counts in Washington, Oregon, and California have resulted in total Snowy Plovers ranging from about 1,520 in the 1990s down to 976 on the 2000 count. By 2008 numbers were back up to a bit below 1,400. The recovery plan includes three primary conservation actions: closing upper beach areas during nesting by roping off or fencing known breeding areas, predator management, and habitat restoration (Page, et al).
Photo credit Becky Matsubara.
References available upon request from amccormick@eastsideaudubon.org.