In an article in Birdscope, summer 1994, vol 8, number 3, a
sidebar to an article about the winter distribution of the
Harris' Sparrow, the editor writes

"As we gathered the data to generate the map that accompanies
this article, we discovered any reports of Harris' Sparrows
in locations that are outside this bird's normal range. We
suspect that what FeederWatchers were actually seeing is the
similar-looking male House Sparrow."

The winter range as determined from FeederWatch sightings (made
by amateurs who happen to watch their feeders regularly and
report the results back to the program) extends well to the
north and west of the range present in the National Geographic.
In fact, the most sightings appear to be in the western part of
the mapped range, if not to the west of it.

The editors attribute the disparity to misidentification:
watchers are confusing the Harris' sparrow with the male House
Sparrow.

IMHO this an a very unlikely error. There are no reported
sightings of this species in the east and perhaps the editors
have not seen a Harris' sparrow. We get them yearly out here in
Victoria (1 or 2 will stay all winter).

If people can distinguish between the two then the error must be
in the range maps. Is this possible?

It seems to me that while this set of observers may not be as
skilled as the set of observers whose data went into the
existing range maps, there are so many more of them spending so
much more time at it, that we should expect different and
perhaps better results.

These improved results would of course only apply to those
species that show up at feeders. We could not use data from such
a program to make negative inferences about ranges of other
species.


Brent