A Tale of Two Hummingbirds?

Over-wintering hummingbirds have been a staple of birding in the southeast United States for the last 30 years or so, and in my state of North Carolina, it seems that a dozen or so are reported over the course of nearly every winter.  At first glance, the idea of hummingbirds in the winter seems to be an odd one.  There are few birds in North America so obviously tropical, so necessarily tied to flowers and sunshine and balmy summer afternoons on the back porch with some sort of gin-based mixed drink, but these winter residents are generally not our breeding birds, the dainty Ruby-throated Hummingbirds.  These birds are the bulky Selasphorus, nearly all Rufous Hummingbirds.  Feisty, tough as nails, and apparently of the opinion that even the worst Carolina winter is nothing compared to those summers in Rocky Mountain meadows.

This has been a particularly good year for over-wintering hummingbirds in the state, and my little town of Chapel Hill (Go Heels!) has hosted not one, but two Rufous Hummingbirds this winter at two sites not more than half a mile apart.  Despite the fact that the two birds look nothing alike, this has obviously led to speculation that the birds in question may, in fact, be the exact same individual who, over the course of two months, is all grows up.

Is that a reasonable hypothesis?  I’m no expert on Rufous Hummingbird molt, but the original bird, one of those subadults that invites confusion with the ridiculously similar Allen’s Hummingbird, was rough looking.  And according to St. Pyle (patron saint of bird banders), Rufies go through a complete molt between their hatch year and second year, a time that corresponds to the period where the birds in question were in Chapel Hill*.

*if I’m wrong someone please set me straight. 

So is it possible that our bird went from this…

November 2011

…to this?

February 2012

This little red stunner was discovered at the Coker Arboretum on the campus of the University of North Carolina.  Remarkably, and bizarre for a vagrant hummer, it was attending a huge stand of exotic, ornamental, honeysuckles rather than a feeder, lending an air of legitimacy that the feeder-bound hummers sometimes lack.  It just feels wild, and at the very least, I didn’t have to make that awkward call to the homeowner for permission to stake it out.

This second bird, present since the end of February, was a no-doubter Rufous, but still a young bird without the iridescent gorget.   It shows little concern for those coming to see it, the benefit of camping out in a high traffic area on a college campus, and with a little time offers some really amazing looks.

Here’s the kicker though.  The first bird was banded at the feeder, so this second bird, if it is, in fact, the first bird (still follow?) should have a tiny metal band around one of those tiny little legs.  And unfortunately, despite the remarkably fine show this individual has been putting on, no photos have surfaced that can conclusively show that the birds are the same.

I’m certainly willing to entertain the possibility, but for my money, and having seen both of them, I see no reason to think we aren’t so lucky here in Carolina to have enjoyed two separate and unequal Rufous Hummingbirds this winter.

I toss the question to the hummingbird experts out there.  Is this plumage transition a legitimate one?