92Wildlife Conservation Plan for Seabirds

92 Wildlife Conservation Plan for Seabirds

Invasive and introduced species have also been a problem in the past, however, wild pigs, cats and goats have been successfully eradicated from Lord Howe Island (Parks Australia 2010). Rat predation accounts for a small proportion of breeding failures each year (Bester et al. 2007). Eradication of rodents on Lord Howe Island was implemented in June and July 2019 with the final biosecurity check for the success planned for August 2021 (Lord Howe Island Board). The introduced Masked Owl may switch to preying on petrels with the removal of rats, potentially causing problematic declines (Bester et al. 2007), and the plans for its eradication (Milledge et al. 2010) are proceeding following significant population reduction during the rodent eradication baiting phase.

The native Lord Howe Woodhen (Hypotaenidia sylvestris) is known to prey on eggs and young chicks and is known to be a significant source of nesting mortality (Bester et al. 2007). Wedge-tailed Shearwaters are also problematic, known to evict smaller petrels from burrows, they have been seen to kill chicks in the small population on Phillip Island (Pridel et al. 2010).

This species is at risk from flooding due to heavy rains and the flooding of burrows represented the main cause of breeding failure on Lord Howe Island in the 2000 and 2001 breeding seasons (Bester et al. 2007). Although flooding is unlikely to kill adult birds, it kills eggs and chicks through chilling and can weaken burrows, causing them to collapse (Bester et al. 2007).

The Providence Petrel is at risk from drowning due to entrapment in fishing gear, however, this is not thought to be a significant source of mortality (Bester et al. 2007). Hunting is known to have severely affected the Norfolk Island population in the past, causing its extirpation (Medway 2002), and it is thought to be unlikely to return. Plastic ingestion may also represent a minor threat, with plastic found in the stomachs of over 10 per cent of the birds sampled (Bester et al. 2010), however, this is not known to have any adverse consequences to the population.

 Quantify the breeding population on Lord Howe and Phillip Islands

 Implement best practice quarantine measures at breeding colonies to reduce the risk of any invasive species (re)establishing on islands

 Re-establish the Norfolk Island colony

Wildlife Conservation Plan for Seabirds 93

Mottled Petrel (Pterodroma inexpectata)

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TABLE Species information for the Mottled Petrel (Pterodroma inexpectata)

The Mottled Petrel (Pterodroma inexpectata) is a medium sized gadfly-petrel, similar in size and structure to Soft-plumaged Petrel (P. mollis). The species is virtually unmistakeable because of the combination of frosty grey upperparts with dark M-mark across the upperwings. Underparts are white with a large grey belly patch and mainly white underwing marked with a broad black diagonal bar across the secondary coverts. The species is an endemic breeding seabird to New Zealand. It breeds on islands off Fiordland, the Solander Islands, Foveaux Strait islands, islands around Stewart Island (including Titi Islands, Codfish, Big South Cape Islands, and islets in Port Pegasus) and the Snares Islands (Marchant and Higgins 1990, Heather and Robertson 1997). It once bred throughout the North and South Islands, and possibly the Chatham, Bounty, Antipodes and Auckland Islands (Marchant and Higgins 1990, Heather and Robertson 1997). The species forages widely in Australian waters and the Southern Ocean. It migrates to the north Pacific Oceans far as the northern Gulf of Alaska and the southern half of the Bering Sea (Ainley and Manolis 1979, Marchant and Higgins 1990, Heather and Robertson 1997, Ogi et al. 1999).