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Tetrapod Zoology

Tetrapod Zoology

Amphibians, reptiles, birds and mammals - living and extinct

Noel W. Cusa's brilliant seabird drawings

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ResearchBlogging.orgWhat with my recent effort to write a lot about tubenosed seabirds (specifically, true petrels or procellariids: see links below), I consider it a peculiar coincidence that I happened to chance upon a copy of Ronald Lockley's Flight of the Storm Petrel in a second-hand bookshop. Note that this book (Lockley 1983) is about storm-petrels (hydrobatids), not about petrels proper.

Storm-petrels are small tubenoses, found in oceans worldwide and famous for the 'surface pattering' behaviour they practise while foraging at the sea surface. Some storm-petrels (the mostly southern Oceanites, Garrodia, Pelagadroma, Fregatta and Nesofregatta, grouped together in Oceanitinae) have long legs and proportionally short, rounded wings. Others (the mostly northern taxa grouped together in Hydrobatinae: Hydrobates, Halocyptena and [the paraphyletic] Oceanodroma) have short legs and longer, more pointed wings. The two groups may not in fact form a clade: some studies find hydrobatines closer to albatrosses than to oceanitines (Penhallurick & Wink 2004). Anyway, one of the things I really like about Lockley's Flight of the Storm Petrel is the artwork - in particular, Noel W. Cusa's brilliant, black-and-white-drawings. I previously featured one of them here. In the interests of bringing them to further attention, I'm sharing some (but certainly not all) of them here. They're interesting for several reasons.

 

Many of Cusa's drawings in Flight of the Storm Petrel show storm-petrels being killed, eaten or dismembered by predators. In fact, as you're about to see, there appears to be an unusually high number of pictures where storm-petrels are depicted as unfortunate victims, not as heroes or victors. There are a few ways to interpret this. Maybe Cusa was making the point that life as a storm-petrel is dangerous and nasty, and that they live a risky life where nefarious predators lurk around every corner: owls, raptors, gulls, skuas... This is only partly true - many tubenoses (storm-petrels included) are long-lived for their size and deaths at the hands or bills of predators are comparatively rare (major caveat: feral cats and rats have devastating impacts on many breeding tubenoses, and humans are doing their best to rid the world of albatrosses and other tubenoses via plastic pollution and the fishing industry). Another possible interpretation of Cusa's many drawings showing storm-petrel death and dismemberment is that he was illustrating especially interesting vignettes of storm-petrel natural history - after all, there are only so many times you can illustrate seabirds foraging over the surface of the open ocean. Another interpretation is that he didn't like storm-petrels much. I kid, of course.

In the above drawing, a British or European storm-petrel Hydrobates pelagicus is being beheaded by a Little owl Athene noctua. This scene is inspired by descriptions of this exact interaction, witnessed occurring on Skokholm (off Pembrokeshire, Wales). Lockley (1983) writes that "one day in July 1936 we found a [Little owl] nest ... in a rabbit burrow, with two tiny owl chicks and a larder of nearly 200 corpses of storm petrels, the majority with only the head removed!" (p. 62). Lockley and colleagues actually took the step of removing these owls and of "shooting or banishing" any additional ones from Skokholm, "preferring to protect our petrels rather than encourage this acclimatised importation from Europe" (p. 62). In 1954 the step was taken to remove Little owls from Skokholm entirely (Hayden 2004), and they've since been blamed for a decline in storm-petrels on Skomer. Little owls are native to much of continental Europe but they were introduced to the British Isles during the 1840s, and from here they colonised Skokholm and Skomer during the 1920s. Moving on...

This illustration (above) shows Matsudaira's storm-petrel Oceanodroma matsudairae. The one thing that books always say about this hydrobatine species is that it nests on volcanic islands south of Japan, and you'll note the very obvious Japanese references (art-memes?) in Cusa's drawing - I mean, come on, I don't need to even mention them, do I? Matsudaira's storm-petrel migrates to the Indian Ocean outside of the breeding season, moving all the way west to the coast of Somalia and Kenya. Observations suggest that they migrate through the channel that separates Australia from Indonesia (Harrison 1983). Oceanodroma as conventionally imagined is paraphyletic with respect to the other hydrobatine taxa Hydrobates and Halocyptena. One solution is to lump them all into the same genus (Hydrobates Boie, 1822 has priority); another is to propose a revised taxonomy - and this is at least consistent with the apparently substantial divergence dates inferred from amino acid distance data. According to the revised taxonomy, Matsudaira's storm-petrel belongs to the same lineage as the Least storm-petrel Halocyptena microsoma, and thus becomes another member of Halocyptena (Penhallurick & Wink 2004).

Here's more art that might be deemed offensive to storm-petrels. In the above illustration, a Peregrine Falco peregrinus stands over a White-faced or Frigate storm-petrel Pelagodroma marina. If you know Cusa's artwork, you might recognise a similar-looking peregrine featured elsewhere, though this time in colour. I don't know if the illustration is based on a specific observation, but Lockley (1983) does refer to the use of ships as hunting platforms for peregrines that will "strike and kill small birds, including storm petrels, fluttering and feeding in the ship's wake" (p. 154). Some peregrine populations really can be considered specialist predators of seabirds. Incidentally, we also now know that some Gyrfalcons F. rusticolus live at sea for months, resting on sea-ice and subsisting entirely on auks and other seabirds.

Below, skuas (one of the Catharacta species, perhaps C. antarctica) are the bad guys. Skuas are awesome predators - more awesome than you might think, since they can and do kill seabirds similar in size to themselves - but they tend not to bother with storm-petrels since they're too nimble in flight. Lockley (1983) says that a dead or disabled storm-petrel, however, will of course be taken by a skua. The storm-petrel shown here is Wilson's storm-petrel Oceanites oceanicus.

But don't get me wrong, there are about 60 of Cusa's drawings in Lockley (1983), and the ones featuring predation, dismemberment etc. are actually very much in the minority. We end with a flock of Dove prions Pachyptila desolata flying over a stormy ocean (below)...

I hope you like Cusa'a drawings as much as I do and that you enjoyed my showcasing of them here.

For previous Tet Zoo articles on tubenosed seabirds, see...

And for articles about other kinds of seabirds, see...

Refs - -

Harrison, P. 1988. Seabirds: an Identification Guide. Houghton Mifflin Company, Boston.

Hayden, J. E. 2004. The diet of the little owl on Skomer 1998-2003. CCW Contract Science Report 673.

Lockley, R. M. 1983. Flight of the Storm Petrel. David & Charles, Newton Abbott & London.

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

The views expressed are those of the author and are not necessarily those of Scientific American.

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