Cory’s Shearwater, photograph by Paulo Catry

Beneharo Rodríguez (Canary Islands’ Ornithology and Natural History Group, Buenavista del Norte, Canary Islands, Spain) and colleagues have published open access in the journal Biological Invasions on effects of Introduced predators (cats and rats) and nest competitors (such as feral pigeons Columbia livia and Cory’s Shearwaters Calonectris borealis) on Bulwer’s Petrels Bulweria bulwerii in the Canary Islands.

Co-author Airam Rodríguez writes to ACAP Latest News "The bulk of Bulwer's Petrel breeding pairs is currently restricted to geographically small secure breeding sites (mostly marine rocks) due to predation by introduced mammal predators, collisions with electricity transmission wires, road casualties, habitat destruction, and attraction to artificial night lights. We highlight an overlooked threat to these petrel sanctuaries: pigeon competition for nesting sites that can cause more than 7.3% of breeding failure. In addition, we have also compiled a non-exhaustive list of evidence of interactions between feral pigeons and other seabirds (15 species!) across the world."

The paper’s abstract follows:

“Petrels are particularly sensitive to predation by introduced species.  Many populations have reduced their breeding ranges, currently mainly occupying predator-free sites.  Breeding range reduction leads to interspecific competition for nesting sites, which can be detrimental to petrels.  Here, we evaluate how the presence of introduced mammals (cats Felis catus and rats Rattus spp.) and potential competitors for nest sites (Cory’s shearwaters Calonectris borealis and feral rock pigeons Columba livia) shape the distribution, breeding density, and breeding performance of Bulwer’s petrel Bulweria bulwerii on Tenerife, the largest and most densely human populated of the Canary Islands.  We estimated nest density, assessed the role of nest location and physical characteristics of nests on breeding success, and determined causes of breeding failure by introduced predators and competitors.  Nest density was higher in predator-free colonies on marine rocks.  Cat presence was the best predictor of nest density, but it was not correlated with either presence or abundance of competitors.  Breeding success varied between years and colonies but was not related to nest characteristics.  Pigeon competition for nests was the most frequent cause of breeding failure (7.3%), followed by rat predation (6.3%). We also compared petrel and pigeon nest cavities and found considerable overlap in the physical size of nest sites.  Our study provides insights into an overlooked impact of the invasive rock pigeon: nest competition with small seabirds.  We encourage more research on the effects of pigeons on nest density, as well as disease and pathogen transmission, and vegetation changes within seabird colonies.”

With thanks to Airam Rodríguez.

Reference:

Rodríguez, B., Rodríguez, A., Siverio, F., Martínez, J.M., Sacramento, E. & Acosta, Y. 2002.  Introduced predators and nest competitors shape distribution and breeding performance of seabirds: feral pigeons as a new threat.  Biological Invasions doi.org/10.1007/s10530-022-02746-1.

John Cooper, ACAP Information Officer, 02 March 2022

Combating climate change: a translocated Laysan Albatross chick is hand-reared by Pacific Rim Conservation in the James Campbell National Wildlife Refuge, a site safe from sea-level rise; artwork by ABUN artist, Ilana Nimz

Since the beginning of the year ACAP has been collaborating with Artists and Biologists Unite for Nature (ABUN) over January and February on its 39th Project (“World Albatross Day 2022 - Climate Change”) to produce artworks that will help increase awareness of the conservation plight facing the world’s albatrosses.  This the third such collaboration with ABUN.

ABUN #39 was due to have ended yesterday after two months, but it has been extended by Kitty Harvill, ABUN’s co-founder, to the end of March 2022.  This will allow contributing artists to submit more artworks depicting two of the three species of albatrosses that breed in the North Pacific: the Black-footed Phoebastria nigripes and the Laysan P. immutabilis.  These two species have been chosen to feature this year’s theme of Climate Change for World Albatross Day on 19 June (click here).

At risk from storms: Black-footed Albatrosses breeding close to the shore, watercolour and gouache by Flávia Barreto; after a photograph by Eric Vanderwerf

In the first two months of the collaboration a total off 55 artworks has been received, 18 depicting Black-footed Albatrosses, and 37 Laysan Albatrosses.  ACAP looks forward to seeing what the ABUN artists will produce in the next four weeks.

With grateful thanks to Kitty Harvill, Co-founder of ABUN and to all the contributing artists for supporting the conservation of albatrosses with their art.

John Cooper, ACAP Information Officer, 01 March 2022

Wisdom's 2011 chick, marked with band number N333, survived the March 2011 tsunami on Midway Atoll and was sighted the first time on a nest of its own in December 2021, photograph by Dan Rapp

Wisdom, a female Laysan Albatross Phoebastria immutabilis who regularly breeds on the USA’s Midway Atoll National Wildlife Refuge in the North Pacific, is the world’s oldest known banded wild bird.  With an estimated minimum age of 70, she has now reached her eighth decade (click here).  This season she briefly visited Midway but has taken a year off from breeding (click here).

However, this season her chick from 2011, identified by the leg band number red N333, has been sighted raising a chick of its own.  Wisdom was at least 59 years old when N333 hatched.  First sighted breeding in December last year, N333 (believed to be a male due to its larger bill size) is currently busy taking turns with its mate as they feed and care for Wisdom’s “grandchick”.

Survivor of the 2011 tsunami, Wisdom's 2011 chick checks out its egg in January 2022; photograph by Dan Rapp

“Sighting N333 on a nest was a long shot because the nest is not located in a study plot and is approximately 176 yards [160 m] from Wisdom’s nest site near a path to North Beach.  What makes this discovery particularly extraordinary is because N333 as a young chick miraculously survived the March 11, 2011 tsunami triggered by a magnitude 9.1 earthquake off the northeastern coast of Japan.  A massive ocean swell surged across the Pacific that day eventually inundating with water and debris most of Eastern Island and parts of Sand Island killing an estimated 110,000 albatross chicks that were too young to fly plus two thousand adults.”

“When Wisdom returned to Midway Atoll to feed her chick on March 20, 2011, it was a welcomed sigh of relief amidst the devastation. N333 also survived due in part to the location of Wisdom’s nest site.  The out-planting of native species created a protective dune barrier that guards against rising sea swells from flooding the northern side of Sand Island. Wisdom’s nest site is located just inland of this sand dune line.”

Wisdom returns to feed her 2011 chick; photograph by U.S. Geological Survey

N333 was the first of Wisdom’s chicks banded and was previously sighted by Wildlife Biologist Jon Plissner each spring from 2018 through 2021 close to its parents’ nest.

News from the Friends of Midway Atoll National Wildlife Refuge (click here).

Note:  The ACAP Information Officer became a grandfather for the first time at the ripe old age of 74 last September, so the above story particularly resonates with him.

John Cooper, ACAP Information Officer, 28 February 2022

 
A pair of non-breeding Buller’s Albatrosses preen on Solander Island, the female (left) devoting all her attention to a rather contented-looking male, May 2013

NOTE: This post continues an occasional series that features photographs of the 31 ACAP-listed species, along with information from and about their photographers.  Here, Jean-Claude Stahl writes on the globally Near Threatened Buller’s Albatross Thalassarche bulleri that he has studied and photographed over many years.

 
Jean-Claude Stahl (right) and Dominique Filippi (Sextant Technology) at a sealers’ shelter on Solander Island; photograph by Michael Hall

Realistically, I have the French military service to thank for my involvement in albatross research.  My choice back in 1977 was between mud crawling on mock battlefields, or a civilian option to study King Penguins Aptenodytes patagonicus on the sub-Antarctic Crozet Islands.  I chose the latter after a nanosecond hesitation, unaware then that the penguin option would have its fair share of mud crawling.  Begging for more, I returned to the Crozets for two more seasons, with research undertaken on a community of 16 petrel species on East Island with Pierre Jouventin, Jean-Louis Mougin and Henri Weimerskirch.  We also undertook the first surveys of Penguin and Apostle Islands where we discovered new breeding localities of Indian Yellow-nosed Albatrosses T. carteri.

While roaming the penguin beaches on the main Possession Island (Île de la Possession), I got the attention of a rather exotic (to French eyes) visiting bird curator from the Museum of New Zealand, Sandy Bartle.  He invited me to his home country and museum; I went there “for a year” in 1986 and I still live in New Zealand.  I soon got involved in seabird research, briefly on the Auckland Islands with Graham Elliott and Kath Walker and more in-depth on Southern Buller’s Albatrosses T. b. bulleri with programme leader Paul Sagar of the National Institute of Water and Atmospheric Research (NIWA), with whom I have enjoyed working for many years.  The research programme was prompted by worries about interactions with fisheries when little was then known about the bird’s at-sea distribution.

A two and half month-old Buller’s Albatross chick

Buller’s Albatross (known as Buller’s Mollymawk in New Zealand) is one of the smallest albatrosses.  The Southern nominate subspecies breeds only on the Snares Islands/Tine Heke (8700 pairs, 2002) and Solander Islands/Hautere (4900 pairs, 2002) south of New Zealand.  Northern Buller’s Albatrosses T. b. platei breed on the Chatham Islands east of New Zealand (17 500 pairs, 1970s) and the Three Kings Islands north of New Zealand (13 pairs, 1985).  Annually breeding Southern Buller’s Albatrosses start returning ashore in December and lay their single eggs in January-February. The egg hatches after 68-72 days, and chicks are reared for an average of 167 days through the southern winter, fledging mainly in August-September.  Northern Buller’s Albatross breeds about three months earlier.  Adults and chicks migrate to seas off Chile and Peru at the end of the breeding season.

Paul Sagar in a Buller’s Albatross study colony under Subantarctic Tree Daisies on the Snares

During our shared stint of research, Paul Sagar concentrated on demography and the Snares some 100 km south of Stewart Island, complete with a cosy hut.  My focus was on the telemetry of foraging birds, and on a study colony on the Solander Islands, which the New Zealand Department of Conservation wishes to keep a wilderness (so no hut, although I sympathise with the policy).  Solander (1.6 km long, 33 m high) is the largest eroded remnant of an andesitic volcano, a bleak landmark some 40 km south of the Fiordland coast and 60 west of Stewart Island.  Hautere, the Māori name of the island, means “swift winds”, a rather apt description for an outpost close to the windiest weather station in New Zealand at South-west Cape.  Europeans first sighted the island in 1770, when Captain James Cook named them after Daniel Solander, the Swedish naturalist on Cook’s first voyage.  As did many southern islands, Solander had its share of sealing gangs and castaways, with one gang of five stranded there between 1808 and 1813, presumably plenty of time to hone their Buller’s Albatross recipes.  Solander is partly covered by “muttonbird scrub” Brachyglottis rotundifolia and Veronica elliptica scrub, below or adjacent to wind-blasted slopes of Poa foliosa and P. astonii tussock and a taller forest patch of Subantarctic Tree Daisies Olearia lyallii on the summit plateau and Brachyglottis stewartiae, more widespread and down to sea level on the Snares.

The safest if horizontally challenged camping spot on Solander

Access to Solander is by permit only and after strict quarantine procedures by the Department of Conservation.  A helicopter can only land on the boulder beaches at low tide, and the first time we were left stranded was an eerie experience in misty weather, surrounded by fish bins of food and gear and hundreds of New Zealand Fur Seals Arctocephalus forsteri and desperately looking for a camping spot on the side of a pyramid.  Over time, we sampled various “promising” spots that turned out to be a waterfall base, a gravity-assisted boulder field, a seal haulout and a Weka Gallirallus australis playground, all accompanied by the deafening heavy swell.  Wekas (a flightless rail) were presumably introduced by sealers and have seriously depleted the burrowing petrel populations but seem to have little affected the Buller’s Albatrosses.

Part of a study colony (foreground) among Poa astonii tussock and Veronica elliptica scrub vegetation on the north-west corner of Solander

Apart from the storms, the greatest spectacle on the Solander Islands was the synchronised return of non-breeding Buller’s Albatrosses to their prospective colonies - I had become particularly interested in non-breeders, which account for close to half of the birds coming ashore.  This was most spectacular in summer during incubation when flocks of over a thousand birds started wheeling off the cliffs at dawn before returning ashore and literally awakening the place (and us) with their piercing wails.  The by-then presumably exhausted birds trickled out to sea in mid-morning to form large rafts just offshore, with an eerie silence returning to the colonies of snoozing incubators.  In mid-afternoon, whole squadrons of non-breeders returned ashore, and all wailing hell broke loose once again, bodies circling each other, heads bobbing, tails fanning, fights and all, until the final dusk exodus.  Except at full moon, when the racket went on well into the night.

Non-breeding birds ready to take off into a wild Tasman Sea

Speaking of storms, one truly epic day was when collecting diet samples from chicks in the teeth of a massive winter storm in July.  In between sheets of sea spray ascending right past the top of the island, we fought our best to “stabilize” the collecting bucket bobbing frantically in the wind. During a relative lull, the knack was to get the near vomiting chick’s bill somehow aligned with the bucket before “release”.  Needless to say a few samples shot past the rim of the bucket on their way to outer space.

Non-breeding birds displaying, attending nests and preening chicks in a study colony on Solander in May 2013

All in all, I made 11 trips to Solander (three-week trips in February and two-week trips in May and July), as well as eight trips to the Snares.  In the compact Solander study colony, I came to know quite a few birds personally; the placid incubators hardly moving when their bands were checked, the neurotic ones on the verge of nervous breakdowns.  I got particularly fond of a banded non-breeder, although getting close to it would be an overstatement.  From the top of his house-sized rock perch, this particular male kept a near daily watch on my wanderings in the colony - and presumably on passing Buller’s females.  I tried everything: slithering around the rock, whistling in mock disinterest, sprinting to beat the odds.  The cool bird just slid off its perch in a nonchalant glide, returning within sometimes seconds of me giving up the chase (French expletives omitted here).

Telemetry of breeding and non-breeding birds from the Snares and Solanders has revealed a dynamic stage, sex, age and locality dependant pattern which, on present evidence, seems broadly consistent from year to year.  Breeding Southern Buller’s Albatrosses forage up to 1800 km from their colonies, from Tasmania in the west to the Chatham Rise east of New Zealand, and from the Auckland Islands north to the Cook Strait (usually) or top the northern tip of New Zealand (one bird).  Breeders of both sexes undertake mostly long trips during the incubation period, mostly short trips during the brood-guard stage, and a mix of short and long trips during the post-guard stage to mid-June (males, which revert to short trips later in the season) or late July at least (females).  The mid-June change coincides with the dispersal of White-capped Albatrosses T. steadi, although this may not indicate a causal relationship.  Males undertake more short trips than do females, and, during long trips, disperse less far along the New Zealand slope.  When heading into the Tasman Sea they forage over the Tasmanian slope, whereas females stay in the oceanic mid-Tasman.  Females also mostly forage in the mid-Tasman during the pre-laying period, when males undertake mostly short trips. Compared to Snares breeders, Solander breeders, especially females, disperse more frequently to the slope west of New Zealand, both during long and short trips.  Tracked six-to-seven year-old prebreeders dispersed to a staging area off Tasmania after their only documented visit ashore.  Older prebreeders (aged eight to nine years) either made mostly long trips to the same areas as breeders (Tasman Sea and New Zealand slope), or mostly undertook short trips throughout the season.

Actively displaying non-breeders; the right-hand bird makes its piercing “wail” call.  Wails echoing in the cliffs are one of the great soundscapes of Buller’s Albatross colonies

Dietary studies (with Gavin James, also from NIWA) have revealed that fisheries discards (mostly of Jack Mackerel, Hoki and macrourids) accounted for two thirds of solid food by weight during the post-guard period at both Solander and the Snares.  The proportion of discards was greater during long trips, that of squid, salps and non-food items (wood and plastic gloves!) greater during short trips, suggesting that the latter are perhaps aimed at filling up the chick with just about anything.  One item that literally stood out from a chick regurgitation was the beak of a cephalopod subsequently identified as that of a giant squid.  An addiction to discards may well have been associated with the population increase observed on the Snares until about 2005, but the recent decline in adult casts some shadows on this sunny picture.  Watch this space.

Acknowledgements

As well as Sandy Bartle and Paul Sagar, I would like to acknowledge all who have contributed to our research, especially the New Zealand Department of Conservation, Dominique Filippi, Graeme Taylor, Alan Tennyson, Susan Waugh, Bernard West and Chrissie Wickes.  They have all facilitated my trips and made them great memories, despite the sometimes-testing conditions.

Selected Publications:

BirdLife International 2004.  Tracking Ocean Wanderers: the Global Distribution of Albatrosses and Petrels.  Results from the Global Procellariiform Tracking Workshop, 1–5 September, 2003, Gordon’s Bay, South Africa.  Cambridge: BirdLife International.  pp. 26-27.

Broekhuizen, N., Stahl, J.-C. & Sagar, P.M. 2003.  Simulating the distribution of southern Buller’s Albatross using an individual-based population model.  Journal of Applied Ecology 40: 678-691.

James, G.D & Stahl, J.-C. 2000.  Diet of southern Buller’s albatross (Diomedea bulleri bulleri) and the importance of fishery discards during chick-rearing.  New Zealand Journal of Marine and Freshwater Research 34: 435-454.

Sagar, P. M. & Stahl, J.-C. 2001.  Unusual items fed to southern Buller’s albatross chicks.  Water and Atmosphere 9: 5.

Sagar, P.M. & Stahl, J.-C. 2005.  Increases in the numbers of breeding pairs in two populations of Buller’s Albatross (Thalassarche bulleri bulleri).  Emu 105: 49-55.

Sagar, P.M., Stahl, J.-C. & Molloy, J. 1998.  Sex determination and natal philopatry of Southern Buller’s Mollymawks (Diomedea bulleri bulleri).  Notornis 45: 271-278.

Sagar, P.M., Stahl, J.-C. & Molloy, J. 2002.  The influence of experience, pair bond duration, and partner change on breeding frequency and success in southern Buller's mollymawk (Thalassarche bulleri bulleri).  Notornis 49: 145-152.

Sagar, P.M., Stahl, J.-C., Molloy, J., Taylor, G.A. & Tennyson, A.J.D. 1999.  Population size and trends within the two populations of Southern Buller’s Albatross Diomedea bulleri bulleri.  Biological Conservation 89: 11-19.

Sagar, P.M., Unwin, M.J., Stahl, J.-C. & Warham, J. 2005.  Variation in the size of Buller's albatross (Thalassarche bulleri) eggs.  New Zealand Journal of Zoology 32: 171-180.

Stahl, J.-C., Bartle, J.A., Cheshire, N.G., Petyt, C. & Sagar, P.M. 1998.  Distribution and movements of Buller’s albatross (Diomedea bulleri) in Australasian seas.  New Zealand Journal of Zoology 24: 109-137.

Stahl, J.-C. & Sagar, P.M. 2000. Foraging strategies of southern Buller's albatrosses Diomedea b. bulleri breeding on The Snares, New Zealand.  Journal of the Royal Society of New Zealand 30: 299-318.

Stahl, J.-C. & Sagar, P. 2000.  Foraging strategies and migration of southern Buller’s albatrosses Diomedea b. bulleri breeding on the Solander Is, New Zealand.  Journal of the Royal Society of New Zealand 30: 319-334.

Stahl, J.-C. & Sagar, P.M. 2006.  Behaviour and patterns of attendance of non-breeding birds at the breeding colony in a Buller’s albatross Thalassarche bulleri population at The Snares.  Notornis 53: 327-338.

Stahl, J.-C. & Sagar, P.M. 2006. Long and short trips in nonbreeding Buller’s albatrosses: relationships with colony attendance and body mass. The Condor 108: 349-366.

Van Bekkum, M., Sagar, P.M.; Stahl, J.-C. & Chambers, G.K. 2006.  Natal philopatry does not lead to population genetic differentiation in Buller’s albatross (Thalassarche bulleri bulleri).  Molecular Ecology 125: 73-79.

Waugh, S.M., Poupart, T.A., Miskelly, C.M., Stahl, J.-C. & Arnould, J.P.Y. 2017.  Human exploitation assisting a threatened species?  The case of muttonbirders and Buller’s albatross. PLoS ONE 12: e0175458.

Jean-Claude Stahl, Museum of New Zealand Te Papa Tongarewa, Wellington, New Zealand, 25 February 2022