I think most of us in North America have come to the somewhat disappointing conclusion that fall migration is pretty much finished for the year. I mean, once the Dark-eyed Juncos start showing up there’s really no denying it, is there? You’re done. You might as well hang it up and learn to enjoy the next five months of kinglets, crows, and creepers. Here in North Carolina, I’ve managed to avoid seeing the dreaded Juncos for the last few days, though their presence has been noted on the local listserv. I figure until I lay eyes on that Junco, fall migration is still on and anything is possible. You hear that, winter? Anything.
But it’s hard to miss the fact that the warblers tend to be lacking in diversity anymore. The flocks that just a fortnight ago held multiple species in varied, if subdued, hues, now overwhelmingly consist of a single species. The hard-checking, tough-as-nails Yellow-rumped Warblers, who will be here until the last northbound migrants chase them back to the boreal forests in May. We get to see a lot of them around here, and familiarity breeds, not contempt certainly, but perhaps apathy. The first Yellow-rumps of the season are always noteworthy, a week later your shooing them out of the way to see the “better” warblers, and before too long they’re all you’re left with. The streaky gray reminder of what was, and what will be again.
But we are not there yet! The late warblers are in full force though, and a trip out to a local park this past weekend put me in the middle of great numbers of Palm Warblers, bobbing drunkenly in the willows near the lake. I flushed several of them, mostly the brown breasted western subspecies, palmarum.
Also in the Palm sort-of-flock, were a couple of these fantastic “Yellow” Pam Warblers, the eastern subspecies hypochrysea, definitely the less common of the two around here. It’s funny, given how common Palms are at the right time of the year, that I almost never see the two populations together. In the spring their period of peak migration is separated by a week or more. Clearly they have no such compunction about heading south together.
And still there are reminders of the great warbler fall that was. Foraging in the willows with the Palm Warblers was true-blue neotropic migrant still slumming it in North America, a Blackpoll Warbler. Look at those bright legs!
We’ve had a pretty exceptional year for Blackpoll Warblers in the Piedmont, as they generally tend to hug the coast pretty closely as they move south down the Outer Banks and make a huge leap from Cape Hatteras nonstop to South America (look at a map, it totally makes sense). Populations of Blackpolls, along with a handful of other highly boreal warblers like Cape May and Tennessee, tend to ebb and flow depending on outbreaks of Spruce Budworm, a small caterpillar known to be a significant conifer pest, and the birds lay more eggs and have greater nesting sucess in years where the budworms are abundant. I hadn’t heard anything either way, but we’ve had abnormally high numbers of all three of those species moving through the area this fall. It seems to me to have been a good budworm year. Have any other birders in the east seen similarly high numbers of boreal warblers this fall?
The fact that they’re present into late October is notable, but I’m not expecting these birds to stay much longer. The Blackpoll will likely split town this week, with the Palms leaving afterwards. Soon, all we’ll be left with till be the little Yellow-rumps. The ultimate lingerer. And then, and only then the Juncos.
Down goes the curtain.