BIRD OF THE WEEK: September 16, 2016
SCIENTIFIC NAME: Hydrobates markhami
HABITAT: Nests in burrows on islands off coasts of Peru and Chile, and in coastal desert of Chile.
The dark, fork-tailed Markham's Storm-petrel can only be sighted over the cool waters of the Humboldt Current off South America's Pacific coast. Its genus name, Hydrobates, means “water walker,” which describes the way it patters along the sea surface when foraging. It's named for Captain Albert Hastings Markham, who collected the first specimen off Peru.
Threats to this seabird include mining and the construction of roads, which destroy nesting habitat; and light pollution, which disorients newly fledged birds and leads to fatal collisions with buildings and other manmade structures.
The IUCN considers Markham's Storm-petrel to be a data deficient species because of the dearth of knowledge about its nesting sites and breeding population estimates. Recent findings may soon lead to a change in this status, however.
Like others of its kind, including Hawaiian Petrel and Black-capped Petrel, Markham's Storm-petrel spends most of its life at sea. This species feeds both close to shore and offshore, with anchovies, squid, shrimp, and krill its favored prey. However, the bird's diet varies from year to year, especially during El Niño and La Niña events, when changes in water temperature alter food availability.
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The storm-petrels feed by swooping down to the ocean surface, pattering their feet on the water with wings raised in a V as they grab their prey. Markham's Storm-petrel also feeds during brief landings on the water. Interestingly, juvenile birds tend to forage further offshore, while adults are found in greater numbers closer to land.
Until 2013, scientists knew of only one breeding colony of Markham's Storm-petrel, on Peru's Paracas Peninsula. In the years since, Chilean birders and researchers have discovered other nesting colonies in the arid Atacama Desert of Chile.
Like other storm-petrels, Markham's Storm-petrels dig nesting burrows. Extensive deposits of saltpeter—potassium nitrate, which exists naturally in the soil in a white, powdery form—along the South American coast and in the Atacama Desert make ideal nesting areas for them. The holes and crevices found below this saltpeter crust offers potential breeding habitat for huge colonies, and the crust itself is so hard that few predators can break it to access the birds' nests.
This species is socially monogamous, meaning it stays with one partner for the duration of the nesting season. The female lays a single egg in deep in the burrow, and both parents tend the egg and the nestling in shifts.
Funding from ABC's William Belton grant program is helping Chilean ornithologists continue research on the Markham's Storm-petrel. Surveys are under way to determine numbers of nesting birds and identify potential threats at newly discovered sites.
ABC's Seabird Program continues work to protect all seabirds. We support legislation to implement the Agreement on the Conservation of Albatrosses and Petrels in the United States, and have launched an interactive web-based tool to help fisheries avoid accidentally catching seabirds: fisheryandseabird.info.
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