Management of a declining common tern colony

Published source details Morris R.D., Kirkham I.R. & Chardine J.W. (1980) Management of a declining common tern colony. Journal of Wildlife Management, 44, 241-245.
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This study is summarised as evidence for the following.

	Action	Category
	Reduce inter-specific competition for nest sites of ground nesting seabirds by removing competitor species Action Link
	Control avian predators on islands Action Link
	Remove vegetation to create nesting areas Action Link

Reduce inter-specific competition for nest sites of ground nesting seabirds by removing competitor species

A before-and-after study over 13 years at an offshore common tern Sterna hirundo colony in Lake Erie, Canada (Morris et al. 1980) found that the number of breeding pairs steadily increased between 1977 and 1989 following various management interventions but this increase could not be linked clearly to any of them. Interventions were: the erection of signs informing people to avoid disturbing nesting birds (1981), the replacement of nesting substrate following flooding (1988), preventing gulls from nesting and destroying gull nests (1977 onwards) and shooting particular ring-billed gulls Larus delawarensis that were heavily predating tern eggs (three gulls shot in 1987). This study is also discussed in ‘Control avian predators on islands’ and ‘Manually remove vegetation from wetlands’.
Control avian predators on islands

A before-and-after study on an island in Lake Onatario, Canada (Morris et al. 1980) found that the fledging success of common terns Sterna hirundo was significantly higher in May and June 1976 (0.44 chicks/egg laid for 66 eggs) when ring-billed gull Larus delawarensis nests were destroyed and vegetation manually removed from the site, than in May and June 1975, when no gull removal was used (0.18 chicks/egg laid for 217 eggs). Fledging success was still higher if late-laid eggs (laid after 4^th June 1976) were included in the analysis, although all of these died. Despite the increases, only three pairs of terns returned to the site in 1977.
Remove vegetation to create nesting areas

A before-and-after study on an island in Lake Onatario, Canada (Morris et al. 1980), found that the fledging success of common terns Sterna hirundo was significantly higher when ring-billed gull Larus delawarensis nests were destroyed and vegetation manually removed from the site, compared to before management. This study is discussed in detail in ‘Control avian predators on islands’.