André Raine (Kaua‘i Endangered Seabird Recovery Project, Hanapëpë, Kaua‘i, Hawai‘i, USA) and colleagues have published in the journal Pacific Science on the petrel and shearwater populations of Moku‘ae‘ae Rock Islet off the Hawaiian island of Kauai.

The paper’s abstract follows:

“Moku‘ae‘ae Rock Islet is located off the north shore of Kaua‘i and is protected as a Hawai‘i State Seabird Sanctuary. In the late 1970s it was also the site of a cross-fostering project for the endangered Newell’s Shearwater, Puffinus newelli. Few avifauna surveys have been undertaken on the islet, and none since 2007. In 2013 and 2015, we conducted burrow searches across the entire islet to obtain breeding population estimates for each species and to evaluate whether the Newell’s Shearwater had become established as a breeding species after the cross-fostering project. Auditory surveys were also conducted for 2 hr after sunset and 1.5 hr before sunrise, which are the peak calling periods for the Newell’s Shearwater on Kaua‘i. A total of seven seabird species was recorded on the islet, of which three, Bulwer’s Petrel, Bulweria bulwerii; Wedge-tailed Shearwater, Ardenna pacifica; and Red-tailed Tropicbird, Phaethon rubricauda, were confirmed breeding. This is the first time Bulwer’s Petrel has been confirmed breeding on Moku‘ae‘ae. Searches for Newell’s Shearwater did not produce evidence that this species breeds on the islet, suggesting that the cross-fostering project was not successful. Although the islet is small, it represents an important refuge for seabird species. However, high levels of depredation were recorded on Bulwer’s Petrel; we conclude that these were all killed by the introduced Barn Owl, Tyto alba, based on disposition of the bodies and the injuries they had sustained. Management recommendations for the islet include creation of a management plan, annual breeding bird surveys, annual rat monitoring, and Barn Owl control.”

Newell's Shearwater, photograph by Eric Vanderwerf

With thanks to André Raine.

References:

Byrd, G.V., Sincock, J.L., Telfer, T.C., Moriarty, D.I. & Brady, B.G. 1984.  A cross-fostering experiment with Newell’s race of Manx shearwater. Journal of Wildlife Management 48: 163-168.

Raine, A.F., Boone, M. & Banfield, N. 2017.  An updated avifauna of Moku‘ae‘ae Rock Islet, Kaua‘i.  Pacific Science 71: 67-76.

John Cooper, ACAP Information Officer, 10 April 2017

Over the  five-year period 2007 to 2011 70 globally Vulnerable Short-tailed Albatross Phoebastria albatrus chicks were taken from the species’ main breeding site on Japan’s Torishima and hand-fed on Mukojima in the Ogasawara Islands.  Most of the 70 chicks fledged successfully from the island.

However, the ultimate success of a seabird translocation exercise is confirmation of the establishment of a new colony.  This requires the fledglings to return to the translocation site and themselves breed successfully.  ACAP Latest News has previously reported on breeding attempts by Short-tails in the Ogasawaras, including by a translocated bird (click here).

We now learn that a bird raised on the Ogasawaras on nearby Nakodojima (click here) has been reported on Mukojima after three years at sea.  “The wild albatross with an artificially reared mother is believed to have left its nest on Nakodojima, one of the islands in the Ogasawara chain, in 2014, and migrated to the North Pacific Ocean.  The bird was then spotted on Mukojima, an island north of Nakodojima, on March 1 [2017]” (click here).

A translocated and hand-fed Short-tailed Albatross fledgling on  Mukojima

According to the report “four wild albatrosses have so far been born to artificially bred birds in the Ogasawara Islands”.  Small beginnings perhaps, but with a second-generation bird returning to the translocation site things look promising for the establishment of a new (or even two) breeding colonies in time for the Short-tailed Albatross.

See also:

http://www.staradvertiser.com/2017/03/30/news/short-tailed-albatrosses-return-to-ogasawara-islands/

https://www.postguam.com/the_globe/philippines_asia/japan-sees-major-step-in-comeback-of-albatross/article_fa81cbf0-11d6-11e7-9ac0-3be4b20e0edc.html

John Cooper, ACAP Information Officer, 07 April 2017

New Zealand’s Endangered and endemic Hutton’s Shearwater Puffinus huttoni, which breeds only in the vicinity of Kaikoura on South Island, took quite a blow after the earthquake last November (click here).

Hutton's Shearwater fledgling, courtesy of the Hutton's Shearwater Charitable Trust

Latest news is that aerial photography suggests that more than 20% of the Kowhai colony and 30% of the Shearwater Stream colony in the Seaward Kaikoura Range (the only two known) were swept away by landslips caused by the earthquake.

Supporting evidence, now the remaining chicks have been fledging, is that only a few birds have been handed in after been downed by street lights during Kaikoura’s “March's Fly Safe” month, leading the Hutton's Shearwater Charitable Trust to estimate that up to 10% of the 2016/17 cohort of chicks has been lost (click here).

Better news is that according to the Hutton's Shearwater Charitable Trust 12 ”healthy” Hutton’s Shearwaters fledged from Te Rae O Atiu, the fenced coastal translocation site that was not harmed by last year’s earthquake.

Follow the fortunes of the birds at the Hutton's Shearwater Charitable Trust’s Facebook page.

John Cooper, ACAP Information Officer, 06 April 2017

Michael Brooke (Department of Zoology, University of Cambridge, UK) and colleagues have published in the journal Animal Conservation on the fortunes of 181 island seabird populations of 69 species following successful eradication of invasive mammals.  The paper concludes "We encourage eradication practitioners and funders to consider building the cost of long-term post-eradication monitoring into project budgets in order to more accurately quantify the impacts of eradication on seabirds."

The paper’s abstract follows:

“Seabirds are among the most threatened groups of birds, and predation by invasive mammals is one of the most acute threats at their island breeding stations. Island restoration projects increasingly involve the eradication of invasive non-native mammals, with benefits for seabirds and other island fauna. To date, demonstrated benefits of invasive mammal eradication include increased seabird nesting success and enhanced adult survival. However, the recovery dynamics of seabird populations have not been documented. Drawing on data from across the world, we assemble population growth rates (λ) of 181 seabird populations of 69 species following successful eradication projects. After successful eradication, the median growth rate was 1.119 and populations with positive growth (λ > 1; n = 151) greatly outnumbered those in decline (λ < 1; n = 23, and seven showed no population change). Population growth was faster (1) at newly established colonies compared to those already established, (2) in the first few years after eradication, (3) among gulls and terns compared to other seabird groups, and (4) when several invasive mammals were eradicated together in the course of the restoration project. The first two points suggest immigration is important for colony growth, the third point reflects the relative lack of philopatry among gulls and terns while the fourth reinforces current best practise, the removal of all invasive mammals where feasible.”

Awaiting the eradication of House Mice on Gough Island: a Tristan Albatross incubates its egg, photograph by John Cooper

Reference:

Brooke, M.d.L., Bonnaud, E., Dilley, B.J., Flint, E.N., Holmes, N.D., Jones, H.P., Provost, P., Rocamora, G., Ryan, P.G., Surman, C. & Buxton, R.T. 2017 Seabird population changes following mammal eradications on islands. Animal Conservation.  doi:10.1111/acv.12344.

John Cooper, ACAP Information Officer, 05 April 2017