I'm grateful to Bill Whan and Vic Fazio for going to so much effort to
confirm that I was correct in my comments about the timing of Forster's Tern
arrival.  To recap: they pointed out that there are a few records at the end
of March (notably early) and more for the first week of April (on the early
side), so that multiples in northwest Ohio on April 12th would be, as I
wrote earlier, right on time.

As birders, we often have a tendency to focus on early and late records
rather than on the normal timing of migration.  These extreme records are
more fun, but from a biological standpoint they're not as important.  As an
example of the "fun" aspect: last fall, as I reported on this listserve, I
found a Yellow-billed Cuckoo at Metzger Marsh on October 31 (not Nov. 1, as
reported in the ohio cardinal).  That cuckoo was a very late bird.  It
didn't set a record -- the species has been found in Ohio in November a
number of times -- but these occurrences notwithstanding, the important
thing to note is that the vast majority of Yellow-billed Cuckoos have
departed for the south before the middle of October.  We know that because a
lot of observers have gathered a lot of information over multiple years.
This points up the great value of keeping notes and recording the numbers of
individuals that we find each day, not just the extreme dates for each
species, to try to get a picture of peak numbers and the actual span of the
typical migration season for each bird.

When we talk about timing of migration, we have to avoid falling into the
trap of making generalizations about the state of Ohio as a whole.  There
are substantial differences in timing in different regions of the state.  In
spring, some migrants have returned to southern Ohio in numbers before
there's any hint of them in the northern tier of counties.  But even at the
same latitudes, there can be differences.  In looking at two local
publications, Birds of the Cleveland Region (by Larry Rosche) and Birds of
the Toledo Area (by Matt Anderson et al.), I frequently find that they give
slightly different timing for the migration of a given species.  Part of
that may be coincidence, with the data skewed by a few odd records, but part
of it may reflect genuine differences between northwestern and northeastern
Ohio.  And in an era of changing climate, the timing of migration may change
in unpredictable ways in the future.  It's always worthwhile for birders to
keep detailed records on the occurrences of birds in their own area, and not
just assume that the important stuff already has been determined elsewhere.

Kenn Kaufman
Rocky Ridge, Ohio

______________________________________________________________________

Ohio-birds mailing list, a service of the Ohio Ornithological Society.
Our thanks to Miami University for hosting this mailing list.
Additional discussions can be found in our forums, at www.ohiobirds.org/forum/.

You can join or leave the list, or change your options, at:
http://listserv.muohio.edu/scripts/wa.exe?LIST=OHIO-BIRDS
Send questions or comments about the list to: [log in to unmask]