Piping Plover
)
Populations of the Piping Plover
(Charadrius melodus) have declined across much of North America in recent years, and the
species is now considered to be
endangered or threatened in all areas of its breeding and wintering range within the United States and Canada. The species is currently designated as being
endangered under the Alberta Wildlife Act.
In Alberta, and elsewhere on the Great Plains, the Piping Plover inhabits shorelines and islands of large alkaline lakes. Nesting typically occurs on gravel substrates in areas with relatively wide,
sparsely-vegetated beaches.
)
Suitable nesting areas are usually localized on lakes, so Piping Plovers typically have a clumped distribution, with several birds nesting close to one another. The availability of suitable nesting substrates for Piping Plovers is intimately linked to seasonal and annual variations in water level on nesting lakes. Periodic
high-water events may restrict beach width and temporarily limit the availability of nesting
habitat, but eventual recession of water levels exposes unvegetated shorelines and gravel deposits which provide breeding habitat for several years thereafter. Prolonged periods of low water allow vegetation to encroach onto nesting beaches, which reduces habitat suitability until high water returns. Annual variations in water levels are typical in prairie
ecosystems, and habitat availability for plovers on a given lake will differ between years. Thus, an absence of birds at a site in a particular year does not necessarily mean the habitat is permanently unsuitable, provided that the natural hydrology of a basin is maintained. The large saline basins occupied by Piping Plovers on the Canadian prairies are generally unsuitable for cultivation, and have not been drained or modified to the same extent as small, fresh wetlands in this region. However, hydrological changes resulting from human activities may threaten the suitability of habitat on several traditional nesting lakes in Alberta. Thus, the possibility of slow,
long-term declines in habitat availability is a concern for Piping Plovers in this province.
Piping Plovers arrive on the breeding grounds in Alberta in late April. Males establish territories that average about 3 hectares in size and most first nests are initiated in early May, but eggs have been reported as early as 30 April in this province. Renesting occurs if loss of the first nest occurs before
mid-June, with the latest clutch initiation for Alberta being in early July. The Piping Plover is a ground nester, and
well-concealed eggs are laid in a shallow scrape lined with small pebbles. Clutches of four eggs are the norm, although
three-egg clutches are common, and five-egg clutches have been reported. Males and females share in incubation of the eggs, which spans 26 to 28 days. The young leave the nest within several hours of hatching, and are capable of sustained flight at about 28 days of age. Reproductive success is highly variable between lakes, and between years across the breeding range of the Piping Plover.
Most birds leave the Canadian prairies for wintering grounds along the Gulf Coast of the
United States, Mexico and the Caribbean by the end of the first week in August. Birds have been known to disperse up to 1,500
kilometres from one breeding season to the next. A single bird may
attain an age of 14 years.