Increasing breeding success of an Endangered penguin: artificial nests or culling predatory gulls?

Published source details Pichegru L. (2013) Increasing breeding success of an Endangered penguin: artificial nests or culling predatory gulls?. Bird Conservation International, 23, 296-308.
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Summary

Provide artificial nesting sites for burrow-nesting seabirds

A replicated, randomized, controlled, before-and-after study in 2009–2011 on Bird Island, Eastern Cape, South Africa (Pichegru 2013) found that introducing artificial nests and controlling predators increased survival of African penguin Spheniscus demersus chicks, but hatching success was lower in one type of artificial burrow compared to natural nests. Kelp gull Larus dominicanus control significantly reduced penguin egg predation, from 4.5 eggs/day before control to 1.9 eggs/day after control. Gull control also reduced numbers of gulls, attack rates on penguin nests and the success rate of attacks (before control: 12–77 gull attacks/h; after control: 4 gull attacks/h; see paper for more data). Fibreglass burrows had lower hatching success than both surface and pipe nests (reported as statistical model results). Chick survival increased significantly after culling in natural surface nests but remained lower compared to both types of artificial nests (reported as statistical model results). Kelp gulls were controlled in 2010 to reduce penguin nest predation. In 2009 artificial nests were introduced: 150 fiberglass nests and 50 cement pipe nests, and were compared to 70–100 randomly selected natural surface nests.

Control avian predators on islands

A replicated, randomized, controlled, before-and-after study in 2009–2011 on Bird Island, Eastern Cape, South Africa (Pichegru 2013) found that controlling predators and introducing artificial nests increased survival of African penguin Spheniscus demersus chicks, but hatching success was lower in one type of artificial burrow compared to natural nests. Kelp gull Larus dominicanus control significantly reduced penguin egg predation, from 4.5 eggs/day before control to 1.9 eggs/day after control. Gull control also reduced numbers of gulls, attack rates on penguin nests and the success rate of attacks (before control: 12–77 gull attacks/h; after control: 4 gull attacks/h; see paper for more data). Fibreglass burrows had lower hatching success than both surface and pipe nests (reported as statistical model results). Chick survival increased significantly after culling in natural surface nests but remained lower compared to both types of artificial nests (reported as statistical model results). Kelp gulls were controlled in 2010 to reduce penguin nest predation. In 2009 artificial nests were introduced: 150 fiberglass nests and 50 cement pipe nests, and were compared to 70–100 randomly selected natural surface nests.