6 
wintering range. The only identification problem is subspecific and this 
is best solved down a gun barrel. 
Ashy Petrel Oceanodroma homochroa 
Still a mystery bird on the Grid. This is the closest breeding 
Storm Petrel to the Grid (in low numbers* albeit)* but it hasn’t turned 
up in Grid collections or even been tentatively seen. I think the non¬ 
breeding birds must stay very close to the coast all year round; in such 
areas as Monterey Bay perhaps. It remains a possibility though, espe¬ 
cially around Points Ash or Dogwood perhaps in late summer. Identifica¬ 
tion* especially from a large ship where the upperwings are often 
obscured* is difficult* and the possibility* perhaps very remote* of con¬ 
fusion with a Dark-rumped Leach is (for me) the most touchy identification 
problem among the local Storm Petrels. 
Wilson’s Storm Petrel Qceanites oceanicus 
Just barely even expectable. Identification is not difficult to 
experienced observers* and is not seriously included among the abreviation 
"WRSP" for ’’White-rumped Storm Petrel.” 
Least Storm Petrel Halocyptena microsoma 
Highly unlikely at any distance from land let alone as far north as 
the Grid. Not impossible but I would be highly sceptical without the 
specimen. 
Black Storm Petrel Oceanodroma melania 
Erratic* but evidently on the Grid. Can be confused with large 
nominate Leach’s if flight pattern is used as main field mark. Next to 
Ashy the only other bird that causes specific identification problems 
with Leach’s. 
Leach’s Storm Petrel Oceanodroma leucorhoa 
Taxonomically a mess. Upon carefully glassing a Storm Petrel on the 
Grid, Fork-tailed, Black, Least, and (by mostly common sense) Ashy can 
be eliminated quickly. Which leaves only Leach's. Thus far it appears 
that virtually (but not quite allI) dark-plumaged Storm Petrels are indeed 
Leach’s* but the possibility of the others occurring must not be entirely 
overlooked. ADP coding is a problem because of rather artificial sub- 
specific nomenclature. In the field any one of the three or four southern 
forms may appear dark-rumped. The taxonomic problem should not be decided 
on the bow however and nothing is lost if all Leach’s are coded 123^-09 and 
their plumage, behavior, size* etc.* recorded under remarks for future tabu¬ 
lation in the report. The species reliability code should be left to your 
judgment or conscience. I would use M 0 M 95 percent of the time. 
