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 Post subject: Petrel, White-chinned
Unread postPosted: Sun Sep 02, 2012 12:34 pm 
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Legendary Virtual Ranger
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The adult population of the White-chinned Petrel, Procellaria aequinoctialis is showing a dramatic decline mainly due to unintentional death at the hands of long line fisheries. An overall decline in population is inferred by a drop in burrow occupancy rates ranging from 15 to 86 percent at breeding colonies.

The WCP remains one of the more common birds sighted during a pelagic out of Durban harbour.

Image

Seen during a pelagic off Durban harbour, the WCP below displays (partial) leucism with the white ring seen around its eye.

Image

In researching leucism in WCPs I came to the conclusion that as many as 10% of all WCPs may display some sort of deviation from the WCP plumage standard, mostly variable sized white patches on the belly. Birds with a white eye-ring like this bird are not frequently seen. Steve N. G. Howell in his paper "Identification of “Black Petrels”, Genus Procellaria", refers to single specimen seen in his considerable encounters with WCPs. In surfing the webz to find a similarly coloured individual, apart from the reference to the bird in the Howell paper, I came up empty-handed.

I can only conclude that this specific colour pattern is scarce and that one must guard against making erroneous ID calls when confronted by such a bird.

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