Is there a good reference for identifying the subspecies of Canada Goose?
Does anyone know which subspecies of Canada Goose occur in Maryland and
what are the relative abundances?

Now that we are talking about Cackling Goose being a bona fide species, I
expect to see an increase in interest of identifying these critters.  And
at least initially, I expect to see a large increase in the number of
reports of misidentified birds.

When I have nothing better to do (which isn't very often), I look through
Canada Goose flocks in an attempt to see differences between the birds.
Most of us will probably begin looking at body size and bill shape this
fall but it is not just a matter of big and long versus small and stubby
since I see a fair number of birds that seem intermediate in both
characteristics.  Presumably, these are other subspecies of Canada Goose
that are not (yet?) split.  There are also plumage differences (breast and
back color for example) but I have not taken the necessary time in the
field to work out the details of these intermediate birds.  Sometimes a
large fraction (>10%) of the smallish birds will have a black chin strap.
I'm calling the smallest and stubbiest billed birds I see Richardson's
because there seems to be a gap in characteristics between them and the
small, but not tiny birds that are presumably some other subspecies.  I
don't know with certainty that these birds are far enough down the curve
to fit into what will be called Cackling Goose.  It is not sufficient to
just look for the two extremes since the smallest bird in a flock is
usually not a Cackler.

A discussion now about which goose subspecies are likely (or at least more
likely than Richardson's) and how to tell them apart will go a long way
toward educating most of us.  Since I'm mostly ignorant of the details,
does anybody want to get the ball rolling?

Dave
David Mozurkewich
Seabrook, PG MD USA
mozurk @ bellAtlantic.net