Posted by John Boyd on October 02, 2003 at 22:52:41:
In Reply to: Re: NAMC Results: Miami-Dade County posted by Brennan Mulrooney on October 02, 2003 at 13:47:42:
Normally, we would expect more Northerns (and more total waterthrushes). Last year, NOWA's were migrating on count day and the total for Miami-Dade was 19 NOWA, 1 LOWA. My own records indicate that about 3/4 of my September waterthrush sightings in Miami-Dade that could be specifically ID'd were Northern (24 of 31 birds).
That said, I think you're right that habitat preferences are also involved. Dunn & Garrett mention that NOWA is fond of mangroves while LOWA is not normally found there or in coastal swamps. After you brought this up it occurred to me that NOWA also seems much more common in drier habitats and D&G confirm this. Besides its well-known fondness for running water (e.g., my group's count bird), LOWA apparently likes linear habitats (think Snake Bight & Bear Lake trails). I don't think there's much LOWA habitat in the Keys.
: Yes, I understand that it's not unheard of for 1 or 2 LOWA's to winter in S. FL, but that's compared to many more (100's?) of NOWA's that do, and it was the peak of their migration. I guess I'm biased, spending most of my time in the keys. NOWA's do seem to prefer mangrove habitat that's much more abundant down here and was probably not covered as thoroughly on the mainland. I probably saw over 50 NOWA's wintering in FL Bay last year and I've seen multiple NOWA's in just about every day of birding this fall, so I tend to think of them as the default waterthrush, but maybe that's not true on the mainland. I assume it was just a matter of the NOWA's prefering a habitat that the Dade count didn't really cover or doesn't contain much of. Does that sound plausible?
: Brennan Mulrooney
: Cujoe Key, FL
: : An La. Waterthrush also wintered at Corkscrew in 2001-02.