There is a bench up on the berm path at Fort Zach that I forget about on a regular basis. It’s a small thing, a one-seater, concrete covered with pale Cuban tiles, and it is not actually on the berm path, but off to the side and down the hill a bit toward the moat path.
I always see the bench and think I would like to be the kind of person who could sit there for a while, thinking deep thoughts. But I never actually stop or even think about it very long because when I’m in the park I can never escape the notion that there are birds to be seen, that I could be missing them.
I definitely was not thinking about the bench when I entered the hammock the other day. I was thinking about the fact that it was so windy the shrimp boats were anchored close offshore, and heavy winds often made it harder to find birds. And I was wondering if I was going to see much at all.
Then I made a bet with myself that, this time of year, in what on the calendar is peak migration season, wind or no wind, if I stared down at any 10-by-10 foot section of fallen leaf litter for a minute, I was likely to see an ovenbird doing a low-key strut through it.
It was a bet I won several times on the first bit of the trail. And, well, it wasn’t just ovenbirds. I saw a solid 10 species of warblers in fewer than 100 yards. When I got to the bench, it wasn’t an aha moment or anything. I just sat and didn’t move much.
Pretty quickly the birds seemed not to notice me. A trio of palm warblers chased each other around close to my feet. A black-and-white warbler hung upside down from a branch close enough that I thought about booping it on the bill. An ovenbird came so near I almost needed my reading glasses to see the little orange stripe on top of its head.
And then there were the yellow with black streaks prairie warblers, the slate-y blue northern parulas, the Cape May warblers with their yellow faces and red cheeks.
I’ve seen bigger, more diverse fallouts, but this was a late afternoon of pretty good migration action.
The birds that kept catching my eye, though, over and over again, were the black-throated blue warblers. Because they always do.
Black-throated blues are attention-getters for a number of reasons, some of them subtle. There’s the white underside and the nominate black throat, though the black extends around the face and all the way above the eyes. There is the blue of their wings and crown and back, a blue as deep as the deepest of dusks. There is the small white patch on their folded wings that is often described as resembling a pocket square handkerchief, though for some reason I always think of a checkbox on a form.
There is their habit of spending most of their time in low thickets, all of the characteristics described here constantly changing as they move from shadow to light to shadow.
There is the fact that their name sounds something like a sad song.
I was out at Boca Grande the other day and caught sight of a peregrine falcon as he flew overhead and continued on toward the Marquesas. And I’ve seen a couple thousand peregrines in my life, and I can never not keep my eye on them as long as possible. Same with purple gallinules, reddish egrets, northern harriers, Baltimore orioles, short-tailed hawks, and a few other species. There are just certain birds that have a magnetism, a charisma, a mystery, birds that give you a consistent spark, or even jolt, of something beyond articulation. Black-throated blues are high on that list.
I can still remember the first time I saw one. I was putting laundry into the washing machine in the back shed in the middle of a heavy downpour. It was in with the Suriname cherries, this small, cobalt-esque creature chasing bugs among an excess of bright red fruit. (The cherries about the size of his head.)
I can still remember the year that thousands and thousands of them were caught in a spring storm and came down and occupied the Lower Keys for two or three days.
I should point out that so far I’ve been talking about the males of the species. The females are of the same shape, but their color scheme is more of a taupe, gray and olive drab scenario. The main common field mark of both sexes is the white patch on their wings.
Black-throated blues are one of the more dramatically sexually dimorphic species in the warbler family. So different that early ornithologists like Alexander Wilson and John James Audubon thought they were separate species, though Audubon realized his mistake before he published the smaller Octavo version of “Birds of America.” (He blamed the then-deceased Wilson for his mistake.)
Birder slang for them is BT blues, not black-throats, because black-throated greens and black-throated grays are also species.
BT blues are an eastern species, breeding in a swath of states and provinces that essentially follows the Canadian border east from Wisconsin, but also through the higher elevations of Appalachia. South Florida is at the northern edge of their winter range. You might see them a handful of times over a winter, but never in great numbers. It’s during migration that they become most common.
BT blues have a strong sense of site fidelity. In the 1980s and 1990s there was a long-term study that monitored them in both their breeding territories in New Hampshire and their winter territories in Jamaica. They used colored leg bands to identify different birds and monitored them over both seasons.
The startling statistic that came from that study was that the males had about a 50-50 chance of surviving from one year to the next; the females, about a 40% chance. Their monthly survival rate during stationary periods, on both their wintering and breeding territories, was around 99%. Meaning their high mortality rates occurred during their twice-a-year migrations, most likely during water crossings.
I can’t say that this is at the core of my appreciation from them as a species, but maybe that information has crept in at the edge of my perception. Either way, seeing them in the park after they have crossed so much water means they’ve probably made it through the most dangerous part of their journey. Every one we see this time of year has pulled something off.
Mark Hedden will give a talk Saturday, April 25 at 1 p.m. in the Toppino Nature Chapel at the Key West Tropical Forest and Botanical Garden.
