Management and Conservation of Piping Plovers in Alberta
By Mark Heckbert
Peering intently through the spotting scope, I concentrated on the female piping plover making her way toward the first nest. Because of recording the dates these eggs were laid, I knew they should hatch any day now. The female skulked among the rocks near the nest and her male partner lifted off the nest. As they switched positions I detected a slight movement in the nest bowl. Out from under the female wriggled a single, downy, newly-hatched chick. I smiled as I realized how fortunate I was to observe such a rare event. In the case of the piping plover, every chick counts.
The piping plover (Charadrius melodus) is a small shorebird that inhabits open lakeshores, alkali flats, river sand bars and ocean beaches. While most shorebirds migrate to Arctic and subarctic breeding grounds and winter as far south as South America, the piping plover breeds and winters in temperate regions of North America.
Piping plovers breed in three distinct locations in North America: the Northern Great Plains (from Nebraska to the southern Canadian prairie provinces), the Great Lakes and the Atlantic Coast (from North Carolina to Newfoundland). In 1985 the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) classified piping plovers as "endangered" in Canada. This designation meant that the species was threatened with immediate extinction.
Historical information on piping plover population size is limited. There was a significant decline in the late 1800s and early 1900s which is generally attributed to overharvesting by early market hunters. The population rose gradually from the 1920s to 1945 and since 1945, piping plover numbers have declined. An International Census carried out in 1991 found 5,480 adults, of which 1,950 (36 per cent) were found in Canada. In Alberta, only 180 adults were counted in the 1991 census.
Is it a piping plover?
Piping plovers are about the size of a bluebird and are somewhat stocky in appearance. They are the rarest of the six "belted" plover species in North America and to the casual observer, are often confused with the killdeer (two black breastbands) or the semi-palmated plover. The top of the head, back and the wings of piping plovers are the color of dried sand. The most prominent physical markings are the black band across the forehead which runs from eye to eye, white stripe above the eye, single black breastband, bright orange legs and an orange, black-tipped bill. Both males and females are similar in appearance but as a general rule, males have a broader and more distinct breastband and headband. The adult winter plumage, similar to the plumage of juveniles, lacks the black breast and head bands.
Alkali lake habitat
In Alberta, piping plovers breed on open rocky beaches and shorelines of alkali lakes. Suitable breeding habitat is located primarily in the southeastern portion of the province in both the parkland and prairie eco-regions. Piping plovers will nest on the shores of dry lakes. However one of the most critical criteria for high quality breeding habitat is beaches free of vegetation.
High quality nesting beaches are usually composed of a sand or silt base covered with hard-packed pebbles and gravels. Frequently larger boulders are found on these beaches. The dominant light brown color and black and white accent markings on piping plovers enable them to camouflage themselves well in the gravel habitat. Young chicks, often barely the size of a cottonball after hatching, rely heavily on crouching and remaining still among the rocks to avoid detection by predators.
Springs and ground water seeps along shorelines are favorite feeding sites as the moist, warm environment attracts insects. Alkali lakes which provide nesting and feeding sites in close proximity to each other, are the preferred habitat.
Raising their young
Piping plovers return to Alberta in late April and early May and remain on the breeding grounds until late July or early August. Upon arrival in the spring, males set up and defend territories on the nesting beaches and perform various aerial displays in the hopes of attracting a mate. Once paired, mated piping plovers remain together for the duration of that nesting attempt. If the pair is not successful in hatching young on the first try, adults may switch mates for successive nesting attempts.
The female usually lays four light brown, black-flecked eggs in early May. One egg is laid every second day. The nest is a mere scrape in the gravel or sand which the male hollows out and then lines with tiny pebbles. Both sexes share in the incubation of the eggs and this lasts an average of 28 days.
The eggs hatch within several hours of each other and the nestlings remain in the nest for only a few hours. After drying off, the precocial chicks soon begin to forage on their own, mimicking the feeding actions of their parents. They pick at small aquatic and terrestrial invertebrates such as small beetles, flies, worms and crustaceans. Both adults and young are rarely seen in the water but rather spend most of their time feeding on the damp sand or mud within several metres of the water's edge.
The adults brood the chicks frequently and communicate continuously with the young, especially when predators or another disturbance is near. The young piping plovers are skilled at the art of camouflage and use a combination of running and crouching among the rocks to escape from danger. The young must hide effectively as they cannot fly for several weeks. Several days before they fledge, the young chicks begin to frequently flap their wings and jump as they prepare for the first short flights. Most young are fledged between 21 and 30 days.
As early as two weeks after hatching, adult females may migrate, leaving the male to raise the young. Males will accompany the fledglings on a nonstop migration to the Gulf of Mexico. Piping plovers normally migrate in small groups of less than 10 individuals. On the winter range, piping plovers disperse to beaches and tidal mudflats along the Gulf of Mexico, Atlantic Coast and the Gulf Intercoastal Waterway.
High nest losses to predators such as crows, gulls, coyotes, skunks and foxes appear to be a major limiting factor for Alberta piping plovers. Disturbance to nesting habitat from cattle trampling may result in a decline in the quality of the gravel beaches as the footprints from cattle "pock-mark" the nesting area. This reduces the amount of gravel on the surface and it may discourage nest-building activities. Deep footprints may trap young chicks which can't climb out of the holes.
Disturbance from all-terrain vehicles, shoreline development and human activities on nesting beaches threaten piping plovers in Alberta. Nesting pairs are more successful in raising young on undisturbed beaches than on beaches that are used for recreation.
Nesting piping plovers on the Atlantic coast face a much greater threat from human disturbance because of increased recreational use of beaches. High nest loss to predators and from coastal storms which flood nests, continue to limit the Atlantic population. The greatest threat to piping plovers on their winter range is development of beach areas for human recreational purposes. And industrial waste is a constant threat to the fragile marine ecosystem upon which piping plovers depend for food.
Preservation in Alberta
Management efforts in Alberta throughout the 1980s by biologists with Natural Resources Service, (Fish and Wildlife Management) and the Canadian Wildlife Service focussed on obtaining basic information about where piping plovers nested, which threats appeared to be limiting populations and on approximately how many piping plovers were in Alberta.
Conservation initiatives in Alberta in the 1990s have expanded and efforts have begun to secure major nesting areas which are threatened by cattle and human disturbance. Through co-operative efforts with landowners and funding from the North American Waterfowl Management Plan (NAWMP), several major nesting and brood rearing habitats have been fenced in order to limit or prevent cattle access to fragile shorelines. By providing alternate and better quality water sources for cattle, the needs of cattle producers and piping plovers are being met.
Predator exclosures have been used successfully in several locations in Alberta in the 1990s. The exclosures are a wire cage, which when placed over the nest, prevents both avian and mammalian predators from reaching the nest while still allowing the adults and young piping plovers to pass freely to and from the nest. These exclosures have increased both nest and fledging success.
Continued conservation measures such as awareness signs, public education, widespread surveys and research by government and non-government agencies contribute to our awareness about the piping plover and lead to further protective measures. The Western Hemisphere Shorebird Reserve Network (WHSRN), an international venture designed to provide recognition for critical shorebird staging areas, is striving to create a series of secure wetlands for migrating shorebirds. Piping plovers in Alberta will benefit from this initiative as several major wetlands that are either nesting sites or migration stopovers are currently recognized or are candidates for WHSRN sites.
With continued conservation measures, co-operative land use and an informed public, the future appears to be positive for a low but stable provincial population of piping plovers. Because piping plovers nest on only a few lakes in Alberta, any kind of disaster, whether natural or industrial, could cause irreversible damage to the provincial population.
If you see piping plovers:
- Move away from the beach. Their nests and young are practically invisible and are easily stepped on.
- Please obey any signs which advise about activities that should not occur in piping plover nesting areas. Pets should not be allowed to roam on nesting beaches.
If you know about the plight of the piping plover, share your knowledge. In one way or another we can all play a role in preserving endangered wildlife.
(Mark Heckberg is a wildlife biologist with Environmental Protection, Natural Resources Service, Northwest Boreal Region. Sources for this article included:"Piping Plover", one of a series of "Alberta's Threatened Wildlife" pamphlets published by Alberta Environmental Protection, Natural Resources Service and from "Piping Plover", one of a series of pamphlets published by the Canadian Wildlife Service.)