David Hyrenbach (Oceanic Institute, Hawai’i Pacific University, Waimanalo, Hawaii, USA) and colleagues report in ‘Elepaio (Journal of the Hawai‘i Audubon Society) on depths achieved by four diving Wedge-tailed Shearwaters Puffinus pacificus (WTSH) in Hawaii carrying tail/mounted time-depth-recorders (TDRs).  Maximum dive depth attained was 21.8 m.  Both single and multiple (bout) dives were recorded.

“[T]he mean maximum dive depths we recorded for WTSH are shallower than those of related sub-arctic, subtropical and tropical species [of shearwaters].  This result is consistent with anatomical evidence suggesting that WTSH are not deep divers, due to having significantly less laterally compressed tarsi than other diving species, like the Short-tailed Shearwater and the Sooty Shearwater.”

The paper concludes: “[f]uture research could further investigate the ecological context of night-time foraging and dive bouts.  To this end, we hypothesize that single dives and dive bouts indicate solitary foraging events and multi-species feeding flocks involving subsurface predators, respectively."

Wedge-tailed Shearwater, photograph by Alan Burger

Reference:

Hyrenbach, K.D., Gleichman, J.S. & Karnovsky, N.J. 2014.  Diving behavior of Wedge-tailed Shearwaters rearing chicks on Lehua Islet.  ‘Elepaio 74(4): 1-4.

John Cooper, ACAP Information Officer, 24 March 2014

Gaia Dell’Ariccia (CNRS, France) and colleagues write in The Journal of Experimental Biology on the ability of Cory's Calonectris borealis and Scopoli's Shearwaters C. diomedea to detect dimethylsulfide at sea, as a presumed cue during foraging.

The paper’s abstract follows:

“Many procellariiforms use olfactory cues to locate food patches over the seemingly featureless ocean surface.  In particular, some of them are able to detect and are attracted by dimethylsulfide (DMS), a volatile compound naturally occurring over worldwide oceans in correspondence with productive feeding areas.  However, current knowledge is restricted to sub-Antarctic species, and to only one study realized under natural conditions at sea.  Here, for the first time, we investigated the response to DMS in parallel in two different environments in temperate waters, the Atlantic Ocean and the Mediterranean Sea, employing Cory's (Calonectris borealis) and Scopoli's shearwaters (Calonectris diomedea) as models.  To test whether these birds can detect and respond to DMS, we presented them with this substance in a Y-maze.  Then, to determine if they use this molecule in natural conditions, we tested the response to DMS at sea.  The number of birds that chose the DMS in the Y-maze and that were recruited at DMS-scented slicks at sea suggest that these shearwaters are attracted to DMS in both non-foraging and natural contexts.  Our findings show that the use of DMS as a foraging cue may be a strategy used by procellariiforms across oceans but that regional differences may exist, giving a worldwide perspective to previous hypotheses concerning the use of DMS as chemical cue.”

Cory's/Scopoli's Shearwater at sea, photograph by John Graham

Reference:

Dell’Ariccia,G., Cerulier, A., Gabirot, M., Palmas, P. Massa, B. & Bonadonna, F. 2014.  Olfactory foraging in temperate waters: sensitivity to dimethylsulfide by shearwaters in the Atlantic Ocean and Mediterranean Sea.  The Journal of Experimental Biology doi: 10.1242/​jeb.097931.

John Cooper, ACAP Information Officer, 22 March 2014

A recent newsletter article from Bird Island in the South Atlantic carries the strange story of a Wandering Albatross Diomedea exulans brooding a Southern Giant Petrel Macronectes giganteus chick, as told here with permission by Jess Walkup:

“A wandering albatross on Bird Island has surprised the scientists there.  During a regular check on nests one bird was found to have a chick more than a month before the wanderer eggs usually hatch.  After initial confusion and checking of dates the chick was inspected more closely and found to be a southern giant petrel chick!

Southern giant petrel chicks hatch throughout January, and have recently begun to be left alone on their nests while their parents forage on the beaches.  It appears that after its own egg was broken or predated [sic], the female wanderer moved to the giant petrel nest, a few meters away, and ‘adopted’ her neighbour’s chick.  Cross-species adoption is rarely observed in the wild in birds.  The female albatross brooding the chick was herself hatched in 2001 and has not been recorded on the island since then, and although a male albatross had been observed on the original wanderer nest, it has not been seen since the female began brooding the petrel chick.  The scientists say she is very protective of her new ward, but it remains to be seen whether she will attempt to feed the chick, or the chicks’ rightful parents return to claim it.

This is the first case of inter-species adoption (or perhaps “chick-napping”?) that has been seen on Bird Island so they are monitoring its progress closely.”

It is now reported that the chick has died.

Wandering Albatross broods a giant petrel chick, photograph by Jess Walkup

With thanks to Jessica Walkup, Zoological Field Assistant, Bird Island and Richard Phillips, British Antarctic Survey.

John Cooper, ACAP Information Officer, 21 March 2014

Sofía Copello (Grupo Vertebrados, Instituto de Investigaciones Marinas y Costeras CONICET – UNMdP, Argentina) and colleagues have looked at the spatial overlap between albatrosses, chiefly the Black-browed Albatross Thalassarche melanophris, and the commercial fishing fleet operating off Argentina.  Their findings have been published recently in the online version of Journal of Sea Research.

The paper’s English abstract follows:

“Incidental mortality in fisheries is the main at-sea threat albatrosses are facing nowadays.  In this study we used remote sensing techniques to model the degree of spatial overlapping between the Black-browed albatross (Thalassarche melanophris) and Argentine fisheries, assuming this as a proxy of risk for albatrosses.  Eleven tags were deployed on albatrosses during the non-breeding seasons 2011 and 2012 in the Patagonian Shelf.  Their distribution overlapped to different extent with the two coastal trawl, three offshore trawl and one demersal longline fisheries.  The overlap index showed highest values with both coastal fleets, followed by the ice-chilling trawl fleet.  These intersections were located in the Argentine-Uruguay Common Fishing Zone, in coastal areas of the SE of Buenos Aires province, El Rincón estuary and over the shelf break.  The analysis of intersections of focal areas from albatrosses and all fisheries allowed us the identification of thirty-four fishing management units (1° by 1° grid within the Argentine EEZ) classified as of medium, high or very high conservation priority.  Very high priority units were placed between 35 and 38°S in the external mouth of Rio de la Plata, and between 45 and 47°S in neighboring waters East to the hake fishing closure.  Although possible biases due to the limited number of tracked birds and the locations where albatrosses were captured and instrumented, the information presented in this study provides a comprehensive picture of important areas of overlapping during winter that could be used by the fishery administration to prioritize conservation actions under limited resource scenarios”.

Black-browed Albatross, photograph by Juan Pablo Seco Pon

Reference:

Copello, S., Seco Pon, J.P. & Favero, M. 2014.  Spatial overlap of Black-browed albatrosses with longline and trawl fisheries in the Patagonian Shelf during the non-breeding season.  Journal of Sea Research. doi: 10.1016/j.seares.2014.02.006.

Juan Pablo Seco Pon, ACAP South American News Correspondent, 20 March 2014