Some time back I started a series on the remarkable tubenosed seabirds known as the petrels (see below for links). Previous articles introduced the group as a whole before discussing one of the four major petrel clades, the gad
Some time back I started a series on the remarkable tubenosed seabirds known as the petrels (see below for links). Previous articles introduced the group as a whole before discussing one of the four major petrel clades, the gadfly-petrels or pterodromines. The time to finish this series is now well overdue, so here we look at the next major clade: the fulmarines. Look at the ‘consensus’ cladogram below to see how they fit with relation to the other petrel clades. Oh, it should be clear that this is a whistle-stop tour, or introduction, to these birds… there is so much more to say. [Images above by Snowmanradio, T. Müller and © Samuel Blanc]
Fulmarini includes the fulmars (Fulmarus) but also the Antarctic petrel Thalassoica antarctica, Snow petrel Pagodroma nivea, the Cape or Pintado petrel Daption capensis and Macronectes, the giant petrels. These are the robust-billed petrels. They also generally have stockier heads and necks than members of the other petrel groups. Some of them – the fulmars in particular – are superficially gull-like, and as a consequence authors of the 1800s and before sometimes regarded members of this group as “the section of Petrels most closely allied to the Laridae, and forming the connecting link between the two families” (Coues 1866, p. 26).
The genetic evidence grouping these species together is reasonably good. Amino acid distances suggest that they diverged from one another quite a long time ago, with the Pintado petrel lineage splitting off in the Late Oligocene and most of the other lineages (including even the fulmar subspecies) diverging during the Miocene. In discussing these divergence date estimates, Penhallurick & Wink (2004) did say, however, that this amino acid distance contradicts nucleotide distance data and “we suspect that … an error may have confounded the data here” (p. 139). How were these divergence estimates calibrated? Penhallurick & Wink (2004) assumed a molecular clock where 2% of nucleotide divergence occurred every million years - see their paper for the full discussion. I like Penhallurick and Wink’s paper, but I’m duty-bound to remind you that it was heavily criticised by Rheindt & Austin (2005).
The most familiar fulmarines are of course the two fulmars: the Northern or Arctic fulmar F. glacialis and the Antarctic, Silver-grey or Southern fulmar F. glacialoides. Northern fulmars come in both light and dark morphs, with the light one being superficially gull-like in colouration while the dark one is smoky-grey and looks superficially like a shearwater. The very darkest forms are known as dark-dark or double-dark. To confuse things further, intermediates between both forms occur. And three Northern fulmar subspecies have been recognised.
Fulmars (the name apparently comes from the Norse for ‘foul gull’) are unusual among petrels in being highly flexible in choice of nest site: they can and will nest in the mouths of burrows, but they much prefer steep cliffs. They’re also known to nest on flat ground, on scree slopes, on ruins and even on the roofs of buildings (Fisher & Lockley 1989). The Northern fulmar is one of several petrel species that has increased hugely in numbers within recent decades. From a dispersal point originally located in southern Iceland, fulmars have spread south and east over the past two centuries. In the British Isles the species was unique, as a breeding bird, to St Kilda in 1870, yet by the 1970s it occurred around the coasts of virtually the whole of Britain and Ireland. Why fulmars exploded in numbers remains uncertain. An increased availability of waste whale meat and fish products, warming conditions in the north-east Atlantic, and even the spread of a recently evolved population, better able than other fulmars to cope with warmer climes and more flexible in breeding behaviour, have been suggested as contributory factors.
Snow petrels, Antarctic petrels, Cape petrels
Somewhat distantly related to fulmars within Fulmarini is the completely white Snow petrel Pagodroma nivea, among the most distinctive of all petrels [adjacent photo by © Samuel Blanc]. Penhallurick & Wink (2004) recovered it as the sister-taxon to all other fulmarines. There are supposed to be two Snow petrel subspecies (the taxonomy of these two is extremely confusing and I will avoid it here), with P. n. confusa being larger (on average) and with a stouter bill. The suggestion has been made that it’s distinct enough to warrant recognition as a distinct species (Harrison 1988). Specialising on ice-edge prey, the long tail and low aspect ratio wings of 