Out on the water daily, skippers and crew of the tourist vessel MV Monarch endeavour to photograph and document any unusual sightings off New Zealand’s Otago coastline. Apart from the local Northern Royal Albatross Diomedea sanfordi that breed nearby at Taiaroa Head/Pukekura, other albatross species foraging offshore are regularly seen.

On 4 January this year just outside the Otago Harbour the cruise came upon a globally Vulnerable Southern Royal Albatross D. epomophora with a peculiar feature on its bill. From close inspection of two high-quality photographs taken by wildlife guide Aaron Heimann that show both profiles of the bird it appears that a lilac-coloured plastic ring had become wrapped around the upper mandible. Given that the presumed artefact is positioned so far back on the bill it seems likely it was placed there deliberately. In one photo it looks like the object has caused a wound.

Two profile views of the Southern Royal Albatross with a presumed plastic ring around its upper mandible

In flight the Southern Royal Albatross was seen to have ample white feathers on the backs of its wings, so it is presumed it to be an older bird. Its behaviour was much the same as other Southern Royal Albatrosses encountered on the sea surface and in flight. The bird was not observed opening its bill, but it appeared to be healthy and so it was inferred it was still able to forage successfully.

Igor Debski (Science Advisor, Marine Species and Threats, New Zealand Department of Conservation) offers the different suggestion that an artefact had been partly swallowed by the bird leaving a loop tight around the base of the upper mandible. The bird’s apparent lack of obvious signs of stress might, however, count against this. Suggestions from readers what the strange object might be (and how it got there) will be welcomed.

Albatrosses of several species photographed at sea have been reported in ACAP Latest News with other signs of human interference including being daubed with red paint, blotched with oil, carrying fish hooks with trailing lines and with cut-off upper mandibles.

The Monarch is operated by Monarch Wildlife Cruises & Tours, which takes passengers on excursions to view wildlife at sea every day in and around the Otago Harbour, Dunedin, New Zealand.

With thanks to Igor Debski and Junichi Sugishita.  Photographs by Aaron Heimann.

Aaron Heimann, Monarch Wildlife Cruises & Tours with John Cooper, ACAP Information Officer, 23 January 2018

Mark Miller (College of Science and Engineering and Centre for Tropical Environmental and Sustainability Science, James Cook University, Australia, Cairns, Queensland, Australia) and colleagues have published in the journal Marine Ecology Progress Series on Wedge-tailed Shearwaters Ardenna pacifica (globally Least Concern) foraging in association with tuna.

The paper’s abstract follows:

“Foraging with tuna is a well-documented seabird strategy, referred to as facilitated foraging. However, despite this behaviour being considered almost obligatory in nutrient-poor tropical waters, little data exist on its relative importance to individual colonies. Therefore, to examine facilitated foraging under different patterns of nutrient availability, we tracked wedge-tailed shearwaters Ardenna pacifica from 2 colonies, one tropical and one subtropical, situated in waters of contrasting productivity. Shearwater foraging behaviour was assessed relative to oceanographic covariates and predicted distributions for multiple tropical tuna species and age-classes, simulated by an existing ecosystem model (SEAPODYM). Shearwaters from both colonies undertook long trips to deep, pelagic waters close to seamounts and foraged most often at fronts and eddies. Micronektonic and adult tuna age classes were highly correlated in space. Predation between these tuna age classes represents a likely source of facilitated foraging opportunities for shearwaters. At broad spatio-temporal scales, shearwaters consistently foraged in areas with higher predicted adult skipjack and micronektonic tuna densities and avoided adult bigeye tuna. At finer spatio-temporal scales, dynamic ocean features aggregated tuna of all sizes. Enhanced tuna density at these locations increased the likelihood of shearwater foraging activity. Long trips in the tropics targeted oligotrophic waters with higher tuna densities. Long trips in the subtropics targeted enhanced productivity, but in some years shifted to target the same oligotrophic, tuna-dense waters used by tropical conspecifics. We conclude that facilitated foraging with tuna is consistently important to the tropical breeding population and becomes increasingly important to the subtropical population in years of low marine productivity.”

Wedge-tailed Shearwaters

Reference:

Miller, M.G.R., Carlile, N., Scutt Phillips, J., McDuie, F. & Congdon, B.C. 2018. Importance of tropical tuna for seabird foraging over a marine productivity gradient. Marine Ecology Progress Series 586: 233-249. doi.org/10.3354/meps12376.

John Cooper, ACAP Information Officer, 22 January 2018

The Kapiti Island Nature Reserve near Wellington, New Zealand is administered by the Department of Conservation and is open to tourist parties. It has been free of introduced mammalian predators for two decades (rats were eradicated in 1996). Among its prolific birdlife is a breeding population of Near Threatened Sooty Shearwaters Ardenna grisea near the island’s western cliff tops. The island’s shearwaters have been a risk to Wekas Gallirallus australis, an endemic (and flightless) New Zealand rail, that prey upon its eggs and young chicks.

Sooty Shearwater, photograph by West Coast Penguin Trust

Not being an introduced species to New Zealand (although introduced to Kapiti in the 1890s), and having a global status of Vulnerable with a decreasing population, their elimination from the island is assumed not to be an option, so a Weka-proof fence has been constructed to keep them out of the shearwater’s breeding site.

“Departure ramps were included in the construction to allow tītī [Sooty Shearwaters] to safely launch back out to sea from their breeding grounds. Motion sensor cameras will also tell us if any cunning weka have found any weak spots along the fence line. The next steps are to install some small one-way tunnels along the fence line, to give juvenile birds an extra exit route when they fledge. Night surveys of the colony in the New Year will hopefully prove more tītī chicks get that chance this breeding season”.

Read more here.

John Cooper, ACAP Information Officer, 19 January 2018

Ryan Reisinger (Centre d’Etudes Biologiques de Chizé, Villiers-en-Bois, France) and colleagues have published in the journal Diversity and Distributions on a decade of at-sea tracing of marine predators, including seven ACAP-listed species, that breed on Marion Island in the southern Indian Ocean.

The paper’s abstract follows:

“Aim

The distribution of marine predators is driven by the distribution and abundance of their prey; areas preferred by multiple marine predator species should therefore indicate areas of ecological significance. The Southern Ocean supports large populations of seabirds and marine mammals and is undergoing rapid environmental change. The management and conservation of these predators and their environment relies on understanding their distribution and its link with the biophysical environment, as the latter determines the distribution and abundance of prey. We addressed this issue using tracking data from 14 species of marine predators to identify important habitat.

Location

Indian Ocean sector of the Southern Ocean.

Methods

We used tracking data from 538 tag deployments made over a decade at the Subantarctic Prince Edward Islands. For each real track, we simulated a set of pseudo-tracks that allowed a presence-availability habitat modelling approach that estimates an animal's habitat preference. Using model ensembles of boosted regression trees and random forests, we modelled these tracks as a response to a set of 17 environmental variables. We combined the resulting species-specific models to evaluate areas of mean importance.

Results

Real tracking locations covered 39.75 million km2, up to 7,813 km from the Prince Edward Islands. Areas of high mean importance were located broadly from the Subtropical Zone to the Polar Frontal Zone in summer and from the Subantarctic to Antarctic Zones in winter. Areas of high mean importance were best predicted by factors including wind speed, sea surface temperature, depth and current speed.

Main conclusions

The models and predictions developed here identify important habitat of marine predators around the Prince Edward Islands and can support the large-scale conservation and management of Subantarctic ecosystems and the marine predators they sustain. The results also form the basis of future efforts to predict the consequences of environmental change.”

A Grey-headed Albatross, one of the seven ACAP-listed species in the study, carries a tracker at Marion Island, photograph by Kim Stevens

With thanks to Ryan Reisinger.

Reference:

Reisinger, R.R., Raymond, B., M.N., Hindell, M.A., Bester, M.N., Crawford, R.J.M., Davies, D., de Bruyn, P.J.N., Dilley, B.J., Kirkman, S.P., Makhado, A.B., Ryan, P.G., Schoombie, S., Stevens, K., Sumner, M.D., Tosh, C.A., Wege, M., Whitehead, T.O., Wotherspoon, S. & Pistorius, P.A. 2018. Habitat modelling of tracking data from multiple marine predators identifies important areas in the Southern Indian Ocean. Diversity and Distributions DOI: 10.1111/ddi.12702.

John Cooper, ACAP Information Officer, 18 January 2018