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My scoring of the La Jolla Oystercatcher

11:11 am



Reviewing the many photos taken of this individual over the last week I have attempted to use the hybrid index for American and Black Oystercatchers as per Jehl (1985), with the caveat that this index was developed for use WITH PRESERVED SPECIMENS IN HAND and not from photographs of live individuals. Some of the characters are impossible to evaluate accurately from photos but can be estimated. This is my own score of the individual, and may not be accurate. The index does not address juvenal plumages, so this may not reflect the score of the same individual in adult plumage

Upper tail coverts 2, nearly equal black and white
Tail 2, basal quarter of retrices white (estimated)
Chest 3, black chest bordered by ragged edge on upper breast
Belly 6, entirely white, as in palliatus
Under tail coverts 3, mainly white
Thighs 4, entirely white, as in palliatus
Greater secondary coverts 2, 2-5 mm (estimated, some photos show wider)
(width of wing edging in folded wing)
Extent of white wing stripe 2, white markings extend to outer secondaries, but not onto 
primaries  
Underwing coverts 3, mainly white
Axillars 4, white, as in palliatus

This gives a composite score (in my eyes) of 31, thus is an American Oystercatcher in that it scores 30 or more. I look forward to seeing how others score this bird. 


As they say in baseball, it’s more fun when you are scoring at home!

Dan Jehl (NOT the author of the index) 
San Diego