Separation from White-chinned
and Parkinson's Black Petrel in the field is difficult. Size is of limited use
because of individual and sex-related variation. According to Palliser (1999)
size and shape are essentially identical to White-chinned Petrel. Bill shape
and color are critically important. Palliser notes that Westland Petrels (June
and September) have a very dark bill tip with the ungues almost entirely black.
This is can be seen in his picture
taken off Sydney, Australia in June. In his experience, Black Petrels have slightly
less black on the tip and in White-chinned Petrel the bill tip is generally
pale although some might have a slight dusky tone. As with other members of
the group, the yellowish tone to the bill plates varies with age. Alvaro Jaramillo
remarks that '.....the bills of Westland Petrels are thicker [than White-chinned
Petrel], making them appear shorter than White-chinned Petrels. In particular,
the latericorn of Westland Petrels is noticeably wider than that of White-chins.
The nasal tubes are also shorter and not as high on Westland, as compared to
White-chinned Petrels. This makes the tubes (nostrils) harder to actually see
on the Westland Petrel, both in photos and in the field' (Jaramillo, 1999).
Where and When
Photographs on the web
flight Photo from Tony Palliser's collection.
On water Photo from Tony Palliser's collection.
Tony Palliser (1999) [BIRDWG01] 'black' Procellaria petrels. Posting to NBHC Id-Frontiers on 28 Jan 1999
Alvaro Jaramillo (1999)
[BIRDWG01] 'black' Procellaria petrels. Posting to NBHC Id-Frontiers on 27 Jan