Fulmars Macronectes Fulmarus

Procellariidae

Fulmars: Fulmarini

Giant Petrels

Genus Macronectes

Two species:

Southern Giant Petrel Macronectes giganteus

Northern Giant Petrel Macronectes halli

The two Macronectes species are very large petrels of about the size of the smaller albatrosses or Mollymawks.

Southern Giant Petrel Macronectes giganteus Signy Island, South Orkneys
Culmen 93.8 mm; total: 168 mm, adult, unsexed adult, probably female
Courtesey of J.A. van Franeker & Ruben Fijn

Evolution and taxonomy

According to Penhallurick & Wink (2004) the divergence of Fulmarus-Macronectes within the Fulmar lineage dates from ca 7.8 My ago and the two Giant Petrel types seem to have diverged from each other around 2.6 My ago. Bourne and Warham (1966) separated the two forms as full species: M. giganteus and G. halli. Recently Penhallurick & Wink (2004) made a plea for re-establishing the subspecific status of both forms based on their DNA analysis.
Hybrids between both (sub)species have occurred. Distinct forms on the Falklands, Gough Island and the Chathams may be subspecies of M. giganteus and M. halli respectively.

Distribution

The Southern Giant Petrel is the commonest of the two and has a cricumpolar distribution in the Southern Hemisphere from Antarctica to subtropical waters. It breeds on many antarctic and subantarctic islands. The Northern Giant Petrel has also a circumpolar distribution but breeds on islands north of the Antarctic Convergence.

Behaviour

Being very ferocious scavengers they are equipped with heavy bills with an impressive hooked tip and long nasal tubes. Since Giant Petrels have the habit of scavenging in penguin rookeries and seal colonies they are good walkers, unlike the other Fulmars. Giant Petrels have been observed diving to depths of about three meters to submerged carrion, using wings and feet (Van den Hoff & Newbery 2006). They are very agile on the wing and fly with rigidly outstretched and narrow wings, but have a more flapping flight than abatrosses.

Osteology

The skeletons of both Giant Petrels extremely similar. Apart from the large size the skeleton is very much like the other fulmarines. But there are also important structural differences. The sternum shows a certain resemblance to those of the smaller albatrosses, and the pelvis is fully fused, unlike the other fulmars.

Skull

Giant Petrels are easily distinguished from the similarly sized Mollymawks by their long nasal tube, or in case of the bare skull, by the ‘hump’ of the upper mandible. Without bill sheaths there is no way to tell the two species of Giant Petrel apart with certainty. The lachrymals are fused, the cranium rounded. The coloration of the ramphoteca is yellowish to pinkish horn with a greenish tip in M. giganteus and a pinkish tip in M. halli.

Fulmars

Genus Fulmarus

Two species:

Southern Fulmar Fulmarus glacialoides

Northern Fulmar Fulmarus glacialis; three subspecies:

Atlantic Fulmar (Arctic type) F. g. glacialis

Atlantic Fulmar (Boreal type) F. g. auduboni

Pacific Fulmar F. g. rodgersii

The 'true' Fulmars are mid-size and stocky seabirds, superficially resembling grey-backed gulls.

Evolution and taxonomy

There is no doubt about the monophyly of the 'true' Fulmars. Voous (1949) argued that Fulmars originate in the Southern Hemisphere and colonised the Northern Pacific during Pleistocene glaciations. Penhallurick & Wink (2004) suggest that the divergence started already about 5.8 My, which is much earlier. The find of fossil remains of Fulmarus spp. dated at 10-15 My ago in North Pacific deposits is confusing, and makes the picture more complex.
After colonisation of the the northern Pacific the Fulmar is supposed to have found it's way to the Atlantic through the northern passage during an interglacial. After the closing of this passage the Fulmars in the Atlantic became islolated and followed their own evlutionary track. Atlantic Fulmars show considerable variation in (bill) size: small in the Arctic (glacialis) and larger in the Boreal zone (auduboni)(Salomonsen 1965). Van Franeker & Wattel (1982) studied the geographical variation and suggest a recolonisation of the Pacific by Atlantic birds based on an analysis of the distribution of light and dark types in both oceans. Presently one subspecies is reconized for the Pacific: rodgersii and two in the Atlantic: glacialis (Arctic) and aduboni (Boreal)
Former subspecies such as F. g. minor (Baffin Island) and the Pacific F. g. glupischa are not longer recognized.

Distribution

Antarctic Fulmars have a circumpolar distribution and breed in huge numbers on many islands south of the Antarctic Convergence and the coast of the Antarctic Continent (Creuwels et al. 2007, in press). Their winter distribution reaches into subtropical waters along the Humboldt Current. The Pacific Fulmar and the Atlantic Fulmar breed in large colonies on many northern and boreal (Atlantic) islands in both oceans. Winters down to resepctively Baja California and the Iberian Peninsula.
More info on Fulmarus glacialis
The Atlantic Fulmar is a marine litter monitoring species in the Save the North Sea Project.

Behaviour

Both species feed mainly by surface seizing of fish and crustacea. Scavenging offal from trawlers has also become an important foraging strategy. Fulmars are capable of diving (up to 4m) but are not very much adapted to it. The flight of both species is characterised by dynamic soaring on stiff outstreched wings like a small albatross. All Fulmarus species are cliff breeders. They don't make burrows and are poor walkers.

Osteology

Skull

All species and subspecies of Fulmars are rather similar in shape and size. The shape and size of the bills form the main difference.
The Southern Fulmar F. glacialoides has a longer bill than its northern counterpart with a different color pattern. Most of the bill is flesh pink, with some bluish grey around the nostrils and with a dark grey tip to the ungues and sometimes dark cutting edges of the upper mandible. The pinkish and blueish color is caused by the tissue underneath the ramphotecal coating.
The Atlantic subspecies of F. glacialis has a rather heavy and compact skull and bill, although rather slender and small billed birds also occur. High Arctic populations have smaller bills, especially those from Baffin Island. This was formerly considered a separate subspecies F. g. minor. Its slightly smaller Pacific congener F. g. rodgersii has a more slender bill and a less robust skull. The bill color of all Northern Fulmar subspecies is yellowish, getting darker to the tip and with a varying amount of black mottling on and near the nostrils.


Southern Fulmar Fulmarus glacialoides Ardery Island Culmen: 46.0 mm, total: 105.4 mm; unsexed adult Courtesey of J.A. van Franeker & Jeroen Creuwels

Atlantic Fulmar Fulmarus glacialis auduboni The Netherlands Culmen: 41.0 mm; total: 101.5 mm, adult, male.

Atlantic Fulmar Fulmarus glacialis glacialis Texel, The Netherlands. Culmen: 33.3 mm; total: 86.3 mm, adult female. A very small billed individual, probably from high Arctic origin.

Pacific Fulmar Fulmarus glacialis rodgersii; Florence, Oregon, USA Culmen: 36.9 mm; total: 88.8 mm, unsexed adult.

Atlantic Fulmar F. g. glacialis (left) Pacific Fulmar F. g. rodgersi (right)

		More osteology will be shown soon
Sternum	Leg

Literature

Bourne W.R.P. & Warham J., 1966, Geographical variation in the giant petrels of the genus Macronectes, Ardea 54: 45-67

Creuwels J.C.S, Poncet S., Hodum P.J., Van Franeker J.A., 2007, Distribution and abundance of the Southern Fulmar Fulmarus glacialoides, (Polar Biol, Springer Verlag, in press)

Fisher J., 1952, The Fulmar, Collins, London

Penhallurick J. & Wink M., 2004, Analysis of the taxonomy and nomenclature of the Procellariiformes based om complete nucleotide sequences of the mitochondrial cytochreome b gene, Emu, 2004, 104, 125-147

Salomonsen, F., 1965, The geographical variation of the Fulmar Fulmarus glacialis and the zones of marine environment in the North Atlantic, The Auk 82: 327-355

Van den Hoff, J & Newbery, K., 2006, Southern Giant Petrels Macronectes giganteus diving on submerged carrion, Marine Ornithology 34: 61-64

Van Franeker, J.A. & Wattel, J., 1982, Geographical variation of the Fulmar Fulmarus glacialis in the North Atantic, Ardea 70: 31-44

Voous, K.H., 1949, The morphological, anatomical, and distributional relationship of the Arctic and Antarctic Fulmars (Aves, Procellariidae), Ardea 37: 113-122

Photos

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