Andrea Soriano-Redondo (Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Spain) and colleagues have published on-line and open-access in the journal Scientific Reports on the likely effects of a trawler discard ban on increased longline mortality of Scopoli’s Shearwaters Calonectris diomedea in the Mediterranean.

The paper’s abstract follows:

“Fisheries provide an abundant and predictable food source for many pelagic seabirds through discards, but also pose a major threat to them through bycatch, threatening their populations worldwide.  The reform of the European Common Fisheries Policy (CFP), which intends to ban discards through the landing obligation of all catches, may force seabirds to seek alternative food sources, such as baited hooks from longlines, increasing bycatch rates.  To test this hypothesis we performed a combined analysis of seabird-fishery interactions using as a model Scopoli’s shearwaters Calonectris diomedea in the Mediterranean.  Tracking data showed that the probability of shearwaters attending longliners increased exponentially with a decreasing density of trawlers.  On-board observations and mortality events corroborated this result: the probability of birds attending longliners increased 4% per each trawler leaving the longliner proximity and bird mortality increased tenfold when trawlers were not operating.  Therefore, the implementation of the landing obligation in EU waters will likely cause a substantial increase in bycatch rates in longliners, at least in the short-term, due to birds switching from trawlers to longliners.  Thus the implementation of the landing obligation must be carefully monitored and counterbalanced with an urgent implementation of bycatch mitigation measures in the longline fleet.”

Scopoli's Shearwater at sea, photograph by 'Pep' Arcos

Reference:

Andrea Soriano-Redondo ,Verónica Cortés, José Manuel Reyes-González, Santi Guallar, Juan Bécares, Beneharo Rodríguez, José Manuel Arcos &Jacob González-Solís, J. 2016.  Relative abundance and distribution of fisheries influence risk of seabird bycatch.  Scientific Reports DOI: 10.1038/srep37373.

John Cooper, ACAP Information Officer, 01 December 2016

Tomohiro Deguchi (Division of Avian Conservation, Yamashina Institute for Ornithology, Abiko, Japan) and colleagues have published in the journal Animal Conservation on the results of a translocation exercise with Short-tailed Albatrosses Phoebastria albatrus.

The paper’s abstract follows:

“Restoration or establishment of colonies using translocation and hand-rearing can be an effective tool for conserving birds.  However, well-designed post-release evaluation studies for long-lived species are rarely implemented.  We investigated the attendance and breeding attempts of hand-reared short-tailed albatross (STAL) Phoebastria albatrus chicks (n = 69) translocated to a historic breeding island in the Ogasawara Islands, 350 km from the source colony, for 8 consecutive years after the first translocation.  Thirty-nine percent of hand-reared birds (n = 27) returned to the translocation site at least once per breeding season, of which 67% (n = 18) also visited the natal island.  The number of hand-reared birds returning each year was lower at the translocation site (mean: 0.3–2.3 birds per day) versus the natal island (0.4–3.5 birds per day).  The first breeding attempt occurred 5 years after the first translocation.  Three pairs (producing three chicks) recruited to the translocation site or neighboring islands and five pairs (producing nine chicks) recruited to the natal island by 8 years after the first translocation.  Every hand-reared bird that raised a chick paired with a naturally reared bird. At the translocation site and neighboring islands, two hand-reared birds paired with a mate from the natal island and a breeding colony 1850 km away, respectively, while the parents of the third chick were unknown.  Their breeding at the translocation region was observed among conspecific social attractants (decoys, audio playback; one pair) or congeners (two pairs).  Our preliminary results suggest that even though more translocated and hand-reared albatrosses visited and recruited to their natal island compared to the translocation site, the early re-establishment of breeding by short-tailed albatrosses in the Ogasawara Islands 80 years after extirpation would not have occurred without the initial translocation effort.  Further study is needed, however, to fully understand formation of breeding colonies beyond conspecific attraction and philopatry.”

A  colour-banded Short-tailed Albatross translocated as a chick returns to Mukojima 

Read more about the translocation project in ACAP Latest News here.

With thanks to Tomohiro Deguchi.

Reference:

Deguchi, T., Sato, F., Eda, M., Izumi, H., Suzuk , H., Suryan, R.M., Lance, E.W., Hasegawa, H. & Ozaki, K. 2016  Translocation and hand-rearing result in short-tailed albatrosses returning to breed in the Ogasawara Islands 80 years after extirpation.  Animal Conservation doi:10.1111/acv.12322.

John Cooper, ACAP Information Officer, 30 November 2016

Rhiannon Meier (National Oceanography Centre, Southampton, UK,) and colleagues have published in the open-access journal Diversity and Distributions on the foraging behaviour of the Critically Endangered and ACAP-listed Balearic Shearwater Puffinus mauretanicus.

The paper’s abstract follows:

“Aim.  The movement patterns of marine top predators are likely to reflect responses to prey distributions, which themselves can be influenced by factors such as climate and fisheries.  The critically endangered Balearic shearwater Puffinus mauretanicus has shown a recent northwards shift in non-breeding distribution, tentatively linked to changing forage fish distribution and/or fisheries activity.  Here, we provide the first information on the foraging ecology of this species during the non-breeding period.

Location.  Breeding grounds in Mallorca, Spain, and non-breeding areas in the north-east Atlantic and western Mediterranean.

Methods.  Birdborne geolocation was used to identify non-breeding grounds.  Information on feather moult (from digital images) and stable isotopes (of both primary wing feathers and potential prey items) was combined to infer foraging behaviour during the non-breeding season.

Results.  Almost all breeding shearwaters (n = 32) migrated to non-breeding areas in the Atlantic from southern Iberia to the French Atlantic coast, where the majority of primary feather moult took place.  Birds foraging off western Iberia yielded feather isotope ratios consistent with a diet composed largely of pelagic fishes, while the isotopic composition of birds foraging in the Bay of Biscay suggested an additional contribution of benthic prey, most likely from demersal fishery discards.

Main conclusions.  Combined application of geolocators and stable isotopes indicates spatial variation in dietary behaviour and interactions with fisheries.  Our results imply that both pelagic fish and fisheries discards are important components of diet during the non-breeding period, which may have implications for the at-sea distribution of this migratory species.  These findings will contribute to bycatch mitigation in non-breeding areas and provide baseline data that should inform future assessment of seabird responses to changing fishery practices and prey distributions.”

Balearic Shearwater at sea

With thanks to Miguel McMinn for information.

Reference:

Meier, R.E., Votier, S.C., Wynn, R.B., Guilford, T, McMinn Grivé, M., Rodríguez, A., Newton, J., Maurice, L., Chouvelon, T., Dessier, SA. & Trueman, C.N. 2016.  Tracking, feather moult and stable isotopes reveal foraging behaviour of a critically endangered seabird during the non-breeding season.  Diversity and Distributions 1-16.  DOI: 10.1111/ddi.12509.

John Cooper, ACAP Information Officer, 29 November 2016

Lyndon Perriman, Department of Conservation Head Ranger at New Zealand’s Taiaroa Head, has made another interesting report on goings on in the mainland Northern Royal Albatross Diomedea sanfordi colony, this time on the fate of a bird whose body was previously spotted below the colony.  His Facebook report, with minor editing, follows.

Yesterday we received the body of the dead albatross [see here] from the bottom of the cliff.  She was banded GOR, a 36-year old.  Her wing bone had snapped apart indicating a severe hit from the cliff or impact with the rocks below.

GOR and her partner had fledged eight chicks from their 11 breeding attempts (spread over an 18-year period as they are a biennial breeding species).  Four of those chicks are old enough to have spent enough time at sea to return at around four or five years and all four are breeding this season. The three other chicks are yet to return.

This pair last bred in the 2014/15 season.  However, her mate failed to return from sea at around March 2015 when their chick was still young and small.  We had no foster nests to foster that chick to other parents so we ended up playing what we term "musical chick" moving chicks between their nest (where GOR was present) and two other nests (containing the two oldest chicks).  At the same time we supplementary-fed GOR, so that with food in her stomach she would stay at the nest.

We needed to do this as GOR had no food left to feed her chick and if she left the nest to go to sea to feed, her young chick would not survive the night alone.

Each day we would move chick 1 to nest 2, move chick 2 to nest 3 and move chick 3 to nest 1 (and move them to the next nest in the following day, leaving one of the older chicks always at GOR's nest overnight so that if GOR did leave, the older chick probably would survive alone overnight).  We can only do this chick rotation during the first one to two months when parents will readily accept any young chick we place in their nest (they will not go to other nests and feed other chicks, but are fixated on their own nest and therefore look after whoever is in their nest.  After a few months they can recognise their own chick and won't feed nearby chicks).

Our supplementary food is pretty good, but not as good as food from the adult, so by exchanging chicks between three nests it meant that the poorer-quality food we gave GOR wouldn't just be fed to her chick alone, thus avoiding potential problems of that chick caused  by a nutrient deficiency.

With three chicks that look very much alike, and a semi-complicated process of moving chicks once or twice a day it was a bit of a headache for staff arriving each day and working out which nest had which chick and where it had to go to for the day or for part of the day.
But the good news was that after a couple of weeks GOR's chick was large enough to survive time alone and GOR naturally entered the post-guard stage (where in a normal situation both parents leave the nest to go to sea to find food for the chick, returning to feed the chick over the next six to seven months until it fledges).

With GOR now in the post-guard stage, and the other two chicks returned to their parents, it would take both parents to raise one chick.  So over the next seven months we supplementary-fed the chick when GOR was out at sea finding food for her chick.  Feeding four times a week, it was a very long seven months, but it did mean that both the chick and GOR survived.

Like all other Northern Royal Albatrosses after fledging a chick the adults take the next 12 months off (the 2015/16 season for GOR was spent out at sea) before returning to attempt to breed again. However, if she had not accidentally hit the cliff, it would have been another three or so years before GOR would have found another mate, formed a strong pair bond and started to breed once more.

Northern Royal Albatross family at Taiaroa Head, photograph by Junichi Sugishita

View a video clip and read more on the current breeding season here.

John Cooper, ACAP Information Officer, 28 November 2016