Study

Restoration of a multi-species seabird colony

  • Published source details Anderson J.G.T. & Devlin C.M. (1999) Restoration of a multi-species seabird colony. Biological Conservation, 90, 175-181.

Summary

Control avian predators on islands

A before-and-after, site comparison study in 1968–1998 on Petit Manan and Green Islands, Maine, USA (Anderson & Devlin 1999) reported that following control of large gulls, seven seabird species returned to breed and/or increased in abundance. Statistical significance was not assessed. Gulls were controlled from 1984. Three tern species recolonized Petit Manan. They nested in 1968–1979 (2–1,300 nests/species/year), did not nest in 1980–1984, then nested every year 1985–1998 (20–1,370 nests/species/year). Atlantic puffins Fratercula arctica colonized Petit Manan: first nest recorded in 1986, peak of 17 breeding pairs in 1998. Three other seabird species became more abundant after gull control: eider Somateria mollissima (62 nesting females in 1984 vs 1,037 in 1994; both islands), black guillemot Cepphus grylle (16 nesting pairs in 1984 vs high of 156 in 1995; both islands) and laughing gull Larus atricilla (40–150 nests/year 1968–1977 vs 210­–600 nests/year 1984–1998; Petit Manan only). The study notes increases in tern and laughing gull populations, but decreases in eider populations, over a similar timeframe on nearby islands (see original paper for data). Gull control focused on herring gulls L. argentatus and greater black-backed gulls L. marinus. Poison was added to nests (1984–1990). Gulls attempting to nest or harassing other seabirds were shot (1985 onwards). Populations declined but not to zero. Breeding seabirds were surveyed intermittently between 1968 and 1998.

Output references
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