An Interesting Prion
These two photographs, of the same bird, were taken east of New Zealand (early December 2005) whilst I was travelling between the Subantarctic Islands. I identified the bird as a Broad-billed Prion (Pachyptila vittata), based primarily on the size/width of the bill and dark-hooded appearance.

Looking at the photos when I returned home I had my doubts as the bill appears bicoloured (Broad-billed should be all-dark?) and maybe the bird isn’t as ‘hooded’ as first thought!

The bill size and colour could suit Salvin’s Prion P. salvini but the tail band is too broad (and it doesn’t show white outers) – could it be the poorly described taxon, Saint Paul Prion (macgillivrayi)!

I posted a note onto the Newsgroups asking if anyone would like to comment on the identification?

The question of this bird’s identity was put onto various Newsgroups (specialising on identification issues and seabirds) and this webpage had well over 400 hits.

Responses though came from nine people only - this is a difficult genus so the low number was not unexpected! It does confirm the overall lack of knowledge we have in identifying these small dynamic seabirds, particularly whilst at sea!

The features that all kept referring to:

Tail-band – the very broad tail-band could fit only Fairy or Fulmar Prion
Bill – the width of the bill is correct for Fairy and Fulmar but the nail or unguis is too weak for Fulmar and does not reach the nostrils as it would on that species. The colour shown, a pale blue, would be correct
Overall darkness – this due to wear. The bird is likely a non-breeding adult. Wear is evident on the remiges and wing coverts and it was commented that this can produce a ‘brown’ (hence darker) appearance.
Head – the lack of the 'pale face' may be due additionally to the subspecies involved. The race subantarctica is paler faced than turtur.
The bird is a Fairy Prion
It is interesting:
(a) that this bird above appears ‘larger’ and ‘bulkier’ than most Fairy Prions
(b) when comparing prions most books describe the bill of Fairy as ‘small’(!)
(c) this individual is certainly duller and darker-faced than obvious Fairy Prions

For the lively communication, particularly from New Zealand, my thanks to Mike Imber (NZ), Chris Robertson (NZ), Paul Scofield (NZ), Chris Gaskin (NZ), Ross Silcock (NZ, currently US), Pete Milburn (Aus), Edward Soldaat (NL), Robert Podolsky (US) and Pete Fraser (UK)
Click HERE to view diagram of prion bills and more comparison photographs