Short-tailed shearwaters breeding in Australia forage in Antarctic waters

Short-tailed shearwaters Puffinus tenuirostris migrate annually from breeding areas in southeast Australia and Tasmania to the Bering Sea to feed on abundant prey aggregations, mainly euphausiids. Occasionally thousands of shearwaters die of starvation en route, within, or on return from the Bering Sea. Collection of live and dead shearwaters in the southeastern Bering Sea in 1997, 1998, and 1999 allowed us to measure seasonal changes in energy reserves during a major mortality event. As birds lost body mass, lipid mass initially decreased faster than that of pectoralis muscle, but loss of pectoralis mass increased markedly at a body mass around 500 g when lipids were almost depleted (~33 g remaining). Death occurred as body mass approached 426 g. Individuals near this body mass had lipid values permitting estimated flight ranges of 140 to 400 km, a range less than that potentially covered in 1 d by shearwaters searching for prey (440 to 1124 km d -1 ). Seasonal differences in body composition were most striking among body and bone marrow lipid contents, with the lowest values occurring during the die-off in fall 1997 and in fall 1998. The lack of shearwater mortality in fall 1998 may have resulted from more consistent winds that decreased flight costs and from greater availability of alternative fish prey. Our data allow estimates of usable energy stores and flight ranges based on lipid reserves in short-tailed shearwaters. Estimated flight ranges suggest that if feeding conditions are poor near Japan or near other termination points of the transequatorial migration routes shearwaters may have few reserves available to support foraging for food and starvation events may occur. Our findings suggest how their energetic strategies and migration are shaped by seasonal and annual variability of prey during transglobal movements of short-tailed shearwaters between oceanic regions.

Section: Estimation Of Flight Rangesmentioning

confidence: 82%

Determining the body condition of short-tailed shearwaters: implications for migratory flight ranges and starvation events

Baduini

Lovvorn²,

Hunt³

2001

“…In addition to these 3 species, this feeding strategy has been described for the white-chinned petrel Procellaria aequinoctialis (Catard et al 2000) and the short-tailed shearwater (Weimerskirch & Cherel 1998, Klomp & Schultz 2000, and it is suspected to occur in the whiteheaded petrels Pterodroma lessoni and mottled petrels P. inexpectata, because the 2 species are numerous in Antarctic waters in January and February (Veit & Hunt 1991). Adult petrels observed at high latitudes in summer are therefore not only non-breeders or failed breeders, as is generally assumed, but at least some are breeding birds that forage far from their breeding grounds to build up energy reserves and collect food for their chicks.…”

Section: Blue Petrels and Prionsmentioning

confidence: 99%

Diet and feeding ecology of blue petrels Halobaena caerulea at Iles Kerguelen, Southern Indian Ocean

Cherel¹,

Bocher²,

Trouvé³

et al. 2002

ABSTRACT:The food and feeding ecology of the blue petrel Halobaena caerulea was investigated over 4 consecutive chick-rearing periods at Iles Kerguelen. In all years, blue petrels fed on a large diversity of crustaceans and fish, with a small proportion of squid and other organisms. Crustaceans ranked first by number (98%) and second by reconstituted mass (37%). The hyperiid Themisto gaudichaudii and the euphausiid Thysanoessa sp. were the dominant prey items, accounting each for 42% by number, and for 12 and 4% by mass of the diet, respectively. Other important crustacean prey were the Antarctic krill Euphausia superba (2% by number and 10% by mass) and the large shrimp Pasiphaea scotiae (<1 and 5%, respectively). Fish were minor items by number (<1%) but, owing to their large size, they dominated the diet by reconstituted mass (57%). Mesopelagic fish of the families Myctophidae (14% by mass) and Melamphaidae (12%) were the main fish prey together with the gempylid Paradiplospinus gracilis (19%). Adult blue petrels use a 2-fold foraging strategy, performing short trips (ST, 2 d on average) and long trips (LT, 7 d) during the chick-rearing period. Birds fed more on T. gaudichaudii during ST and more on Thysanoessa sp. during LT. The subantarctic krill Euphausia vallentini were found in ST samples, and Antarctic krill and stomach oil were found in LT samples. Biogeography of the prey shows that blue petrels fed in a wide variety of marine habitats. During ST, they foraged in the kelp belt and over the shelf, but favoured oceanic waters in the vicinity of the archipelago. During LT, the occurrence of Antarctic krill indicates feeding in southern Antarctic waters, >1000 km from the breeding colonies, but blue petrels also foraged on their way back to Iles Kerguelen from these distant foraging grounds to feed their chicks. A comparison of the stable carbon and nitrogen isotopic compositions of chick and adult feathers reveals that adult blue petrels fed at the same trophic level during the chick-rearing and moulting period, and that they renew their flight feathers in Antarctic waters. KEY WORDS: Euphausia superba · Mesopelagic fish · Seabirds · Stable carbon isotopes · Stable nitrogen isotopes · Themisto gaudichaudii · Thysanoessa Resale or republication not permitted without written consent of the publisher INTRODUCTIONThe blue petrel Halobaena caerulea is a small procellariiform species that is taxonomically closely related to the prions (genus Pachyptila). It is the sole member of the genus and inhabits the subantarctic and Antarctic zones of the Southern Ocean (Warham 1990). The species is circumpolar and nests colonially in burrows at 6 locations close to the Antarctic polar front. The main population of blue petrels is in the southern Indian Ocean and at Diego Ramirez (Chile) with smaller numbers at Macquarie and South Georgia (Marchant & Higgins 1990). At Iles Kerguelen, the species is numerous (100 000 to 200 000 pairs), and it breeds sympatrically with 3 different prion species: the fairy prion P. turtur a...

“…Observed (black bars) and expected (white bars) distribution of the number of days between when one adult starts a long-trip and its mate returns from the most temporally associated long-trip highly productive foraging areas in high-latitude regions (e.g. Catard et al 2000, Klomp & Schultz 2000. Furthermore, when near-colony resources can sustain both chick and adult requirements as in Hawaii, wedge-tailed shearwaters do not use a dual-foraging strategy (Baduini 2002).…”

Section: 'At-distance' Foraging In Wedge-tailed Shearwatersmentioning

confidence: 99%

“…Catard et al 2000, Klomp & Schultz 2000. Furthermore, when near-colony resources can sustain both chick and adult requirements as in Hawaii, wedge-tailed shearwaters do not use a dual-foraging strategy (Baduini 2002).…”

Section: 'At-distance' Foraging In Wedge-tailed Shearwatersmentioning

confidence: 99%

See 1 more Smart Citation

Dual-foraging and co-ordinated provisioning in a tropical Procellariiform, the wedge-tailed shearwater

Congdon¹,

Krockenberger²,

Smithers³

2005

To sustain breeding while simultaneously compensating for poor local resource availability, many temperate Procellariiformes (tube-nosed seabirds) access highly productive areas 'atdistance' from breeding colonies using a unique dual-foraging strategy. We tested for, and observed, a similar dual foraging strategy in a tropical Procellariiform, the wedge-tailed shearwater Puffinus pacificus. Foraging adults repeatedly performed short-trip cycles of multiple 1 to 4 d trips followed by a single long-trip of ~8 d. As with temperate species, wedge-tailed shearwaters used long-trips to build body reserves that they passed onto chicks by not self-provisioning adequately during the early stages of each short-trip cycle. Unlike temperate species (1) long-trip length and adult mass change during long-trips was inversely related to adult mass at the beginning of the same long-trip, and (2) foraging mode changeover appeared to be co-ordinated and was not initiated by adults reaching some critical lower mass. This implies that the dual-foraging pattern observed in wedge-tailed shearwaters is a consequence of the median time adults require to replenish body reserves on long-trips. We conclude that foraging strategies in wedge-tailed shearwaters vary spatially relative to nearcolony resource availability, and that dual-foraging is a general Procellariiform life-history strategy used to address similar ecological constraints in both temperate and tropical systems. Our findings suggest that wedge-tailed shearwaters of the southern Great Barrier Reef (GBR) may be dependent on localised areas of high productivity 'at-distance' from breeding colonies to sustain breeding.KEY WORDS: Dual-foraging · Co-ordinated provisioning · Feeding ecology · Wedge-tailed shearwater · Puffinus pacificus · Procellariiform · Great Barrier Reef Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 301: [293][294][295][296][297][298][299][300][301] 2005 that dual-foraging can be unambiguously linked to the use of distant highly productive foraging areas in these species.Tropical Procellariiformes face similar energetic constraints, yet it is unlikely that they consistently access the same highly productive temperate waters to compensate for poor local resource availability. This is particularly true of the smaller pan-tropically distributed Procellariiform species, such as the wedge-tailed shearwater Puffinus pacificus. How then do tropical species replenish their own reserves while simultaneously satisfying chick requirements? Two possibilities exist. Firstly, tropical Procellariiformes may use a dualforaging strategy similar to temperate species to access currently unknown, highly productive but more localised foraging zones in the tropics. Limited evidence for this possibility exists. Phoebastria immutabilis (Laysan albatross) and P. nigripes (black-footed albatross) nesting in the subtropics at Tern Island, French Frigate Shoals, Hawaii, both have bimodal foraging trip durations similar to tempe...