Western Snowy Plover


Characteristics of the Snowy Plover:
Were Does It Live?:
What Does It Eat (Feeding)?:
What Eats It (Predation)?:
Nesting Behavior:
Management and Conservation Status:
References:

Introduction:
  The western snowy plover is listed by the U.S. Fish and Wildlife Service as a threatened species.  This species has become threatened as a result of increasing human and environmental impacts on its nesting habitat.  This impacts have forced the snowy plover to move or migrate to different nesting sites in order to reduce these stresses on breeding behavior.
    For instance, many snowy plovers have migrated to the Great Salt Lake during their breeding season to avoid pressures caused by habitat degradation.  On U.S. coasts this habitat degradation is caused primarily by expanding beach front development.  Recreation has also been responsible for a significant decline in the size of breeding populations.  The use of beach grass (Ammophila arenaria) to stabilize dunes along the Pacific Coast has also greatly affected these birds.  This stabilization has reduced the extent of open nesting habitat.  Other impacts include frequent mechanical raking of beaches to remove garbage, seaweed, and other debris which has made beaches in southern California unsuitable for nesting and harms food resources for the snowy plover.  These and other human pressures have caused this species to migrate inland to available breeding habitats such as the Great Salt Lake playa margins. 
   However, while this migration has allowed the snowy plover to avoid pressures along the Pacific Coast, this movement has caused them to encounter other impacts.  The snowy plovers breeding habitat around the Great Salt Lake has been reduced significantly due to long term oscillations and high water years.  In addition, breeding habitat along stream side and lake shorelines has  been invaded by the introduced salt cedar (Tamarix gallica), significantly reducing remaining  nesting habitat.  The access of off road vehicles in certain areas has also cause significant disturbance to nesting areas on the Great Salt Lake shorelines.  These impacts around the Great Salt Lake causing the snowy plover to again move to other more isolated breeding habitats. 

Characteristics of the Snowy Plover:
    The snowy plover (Charadrius alexandrinus) is a small bird ranging from about 15-17 cm long, and weighing between 34-58 g.  This small bird is identified by its breast band always restricted to lateral patches.  The snowy plover also has pale brown upper parts and dark gray to blackish legs, very important in identification.  The western snowy plover is presently on the USFWS Threatened Species List and is cause for concern to wildlife managers in the western United States.
 
 





Were Does It Live?:
    In North America, there are two recognized subspecies the western snowy plover (Charadrius alexandrius nivosus) and Cuban snowy plover (Charadrius alexandrinus tenuirostris).  The western snowy plover nests west of the Rocky Mountains and the Cuban snowy plover resides on the Gulf Coast from western Florida to Texas.  We are obviously concerned with the western snowy plover, which is found inhabiting coastal beaches and interior alkaline lakes, like the Great Salt Lake.  Both coastal and interior populations winter on beaches along the Gulf of California, Gulf of Mexico, and Pacific Ocean.  The interior populations are migratory and use areas, such as the Great Salt Lake to nest at during the summer, and then winter in these southern coastal areas.
 
 





What Does It Eat? (Feeding):
    The western snowy plover mainly feeds on terrestrial and aquatic invertebrates, for instance brine flies, brine fly larvae and brine shrimp.  These birds use several different techniques to capture and consume food items.  In some instances, when dense prey items, such as brine flies are present, they lower their head and charge through prey aggregations snapping their bill and swallowing them quickly.  At other times they pause, look, and then seize prey from the surface of the beach or tidal flats.  They are also found probing for food in sand and mud.

What Eats It? (Predation):
    These small aquatic birds have many different types of predators in the different regions that they inhabit.  Many different birds are predators to this smaller land shore dwelling bird.  For instance, many raptors like the peregrine falcons and other falcons and the northern harrier and other hawks may prey on plovers.  Eggs or nestlings are also fed on by the California gull, the cattle egret and other large birds.  And If this aerial attack were not enough, beach nesting plovers may also be threatened by the red fox, kit fox, striped skunks, raccoons, badgers, and other  carnivorus mammals which may inhabit the playa ecosystem. 

Nesting Behavior:
    These birds create a nest on a scrape or natural depression, with pebbles, shell fragments, fish bones, mud chips, vegetation fragments, or invertebrate skeletons.  Their nesting behavior has been found to be greatly impacted by the use of off road vehicles near their nesting habitat.  However, the primary threat facing plovers today at the Great Salt Lake is nest predation by the red fox (Vulpes vulpes).  A management plan may be needed to relieve this pressure on the western snowy plover.

Management and Conservation Status:
    As mentioned before, the population breeding along the Pacific Coast of the U.S. and Baja California is listed by U.S. Fish and Wildlife as a Threatened species. In Washington and Alabama it has been designated an Endangered species by those states.  These designations have given rise to many measures being taken to protect this animal's habitat.  Some states have posted informative signs and roped of areas to reduce disturbance of nesting birds.  In some states such as Oregon, beaches have been closed.  These and other techniques have lead to improved hatching success.  However, there is still research being done to improve snowy plover nesting and hatching success.  For instance, experiments with solar powered electric fences, chick shelters, and artificially elevated nesting substrates at the Great Salt Plain, Oklahoma, show promise for increasing reproductive success.  All measures to protect snowy plovers have been too recent to determine their effect on population size. 

References:

G.W. Page, J.S. and J.C. Warriner, P.W.C. Paton.  1995.  Snowy Plover. The Birds of North America. No. 154.

Paton, Peter W.C. Breeding Ecology of Snowy Plovers Utah Coop. Fish and Wildlife Research Unit, Dept. of Fisheriesand Wildlife, Utah State University, Logan, UT.  (November 18, 1999).

America's National Wildlife Refugees Where Wildlife Comes Naturally. (June 11, 1997)   http://refuges.fws.gov/NWRSFiles/WildlifeMgmt/SpeciesAccounts/Birds/WestSnowyPlover /WestSnowyPloverIndex.html  (November 20, 1999).


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