97-12-19, an out-of-state 'tweet' writes:

<< I wish I had paid more attention to it beforehand! In further
investigation of the
literature, I realize that the upper wing isn't the critical field mark for
making the ID. Rookie mistake :( >>

##### -- I know the same feeling all too well with countless other things.
Don't despair. We all learn from our mistakes and oversights. In all 99%
probability, the shearwater you saw while crossing the Strait was a Short-
tailed, but I guess that won't help much if in your conscience, you're not
satisfied with the views and field marks you did absorb but overlooked the
critical key ones.

I often actually write down in a notebook before hand; a sort of checklist to
the key differences between two similar species which I may encounter in the
field, then either commit them to memory or carry it along to refer to
directly and tick off the marks as it were. A current local good example here
for me is Red-shafted vs Yellow-shafted Flicker. We get a fair number of
hybrids with a mixed bag of plumages. Reference to my table checklist of
comparative notes helps in making sure that I am not overlooking and
considering all combinations of plumages to determine whether I've found a
full-blooded Yellow-shafted. So far, I haven't, but have come close.

Richard Rowlett (Pagodroma at aol.com)
47.56N, 122.13W
(Seattle/Bellevue, WA USA)