Sweetly singing in the old apple tree
Peak Towhee Past
From out of the 6:30 eastern glow over Laurel Ridge, the black outline of a thrush plummets toward and then past me. Seconds later, a loud, upward peep a walnut’s throw away—Swainson’s, one of the last of the dawn, flight call submerged in the rising chorus of Eastern Towhees and White-throated Sparrows. Later, I’ll comb the fields and woods for those two, but though their numbers are still high, they’re a week past their prime, like almost every other migrant this year.
I’ve been out here under the stars since 5:30, pacing about the barn bank. Merlin is running on the roof of the car, phone mic pointed at the wet area around the base of the amphitheater, the old apple tree at the bend in the driveway just a few yards away. I’ll need all the help I can get if something unusual has dropped in on us since the deluge.
Before the Deluge
Hurricane Helene did to the Southern Appalachians what Agnes did to Pennsylvania back in 1972. This last week, on the cusp of 55, I’ve been getting flashbacks of the three terrible storms that helped shaped my life: Agnes (my first memory), Mitch (Honduras, 1998), and Katrina (Mississippi, 2005). But the only personal toll this time is 11 days of misty rain as the monster remnants refused to move. Because this happened during the peak of migration, birds from the rainless north piled up in migrant traps like Plummer’s Hollow, to the point that around the turn of the month, I was tramping about the swampy fields as Lincoln’s Sparrows, Common Yellowthroats, and House Wrens burst from every bush.
But before all that, two months flew by sans blog, thanks to trips to Florida and California as well as a barn party and the typical insanity of contract work. The birding didn’t stop, though, which you know if you’ve dipped into the eBird hotspot lately. Here are some of the highlights:
197 species for 2024. In the last update, August 12, we were at 193 species. Since then, we’ve added Blue-winged Warbler (Aug 26), Northern Saw-whet Owl (Sept 12, an unexpectedly early NFC), Connecticut Warbler (Sept 13), and Hooded Merganser (Oct 4). Our good options for new species have dwindled to four potential NFCs—Dickcissel, Black-bellied Plover, American Golden-Plover, Snow Bunting)—and a handful of others: Evening Grosbeak (supposedly this will be a decent a flight year), Northern Shoveler (and any other missing duck, of course), Snow Goose, Bonaparte’s Gull. It’ll be close!
An all-time Pennsylvania eBird high count of Gray-cheeked Thrush on Sept 27. This species has been abundant and easy to hear and even glimpse this season. Like Swainson’s, it moved through during the days of the deluge, and was seemingly much closer to the ground (hence louder), due to the continuous cloud cover.
All-time eBird high counts for the hotspot, and in some instances Blair County, of the following species: Common Merganser (35 on Aug 15), Chestnut-sided Warbler (15 on Sept 2), Magnolia Warbler (27 on Sept 2), Chimney Swift (318 on Sept 8), Tennessee Warbler (24 on Sept 26), Common Yellowthroat (43 on Sept 28), Connecticut Warbler (3 on Sept 28), Blue Jay (233 on Sept 28), Lincoln’s Sparrow (100 on Oct 2), House Wren (10 on Oct 2), Swamp Sparrow (15 on Oct 3). The reasons for these high numbers vary, but in some cases, such as mergansers and jays, the counts represent overall upward trends in population. Blue Jays, easily countable in diurnal migration, are responding to high amounts of acorns. Mergansers nested successfully in the area and are generally expanding in numbers. Swifts both nest by the dozens and stop over during migration by the hundreds in Tyrone, thanks to our abundance of unblocked bricked chimneys. I was worried that the demolition of the old brick smokestack over by the paper mill would bring stopover numbers down this year, but my fears were unfounded. I stood in awe as hundreds of them streamed west through the Gap toward town in the rainy dusk of October 1. The last I saw of them was the next evening, and then they all vanished. In terms of the sparrows, wren, and yellowthroat, our typically high numbers climbed even higher as individuals piled up during the deluge, waiting for the weather to clear—a traffic jam, if you will.
Other unusual records included a first-ever summer Peregrine Falcon (Aug 26), perhaps from a nest in the area; a Prairie Warbler on the same day, one of the harder warbler species to get in the fall; a Black-crowned Night Heron on NFC (Sept 3), third for the year; a Solitary Sandpiper on NFC (Sept 6), first-ever for fall; a female Orchard Oriole Sept 15, second-ever for the fall and in the same place as last year—the tops of Norway Spruce in the Grove. Meanwhile, one and sometimes two Red-headed Woodpeckers are regularly at the Far Field, as breeding populations from Sinking Valley continue to expand.
Ahead
The above-mentioned warblers were unusually high in numbers all year, and some lingered beyond their normal leave dates, due in part to the traffic jam. This also applies to Rose-breasted Grosbeaks, an Eastern Whip-poor-will on Oct. 3 (all-time late record for the hotspot and the county), and first-ever October dates for Northern Parula and Hooded Warbler.
However, as I expected, in general the late Aug/early Sept migrant peak numbers were much below last year thanks to the utter failure of the black cherry crop, tied to blight and other factors. The sheer frenzy of years past was muted, with frugivores turning to other food sources or moving quickly south, while insectivores that in other years snap at the clouds of fruit gnats found the pickings slim. Numbers and species diversity were respectable, mind you, but never overwhelming. This applied to early-leaving warblers, vireos, Scarlet Tanagers, Baltimore Orioles, and several others.
Also, as has been the case seemingly since last winter, everything happened a week to ten days early.
We started seeing this with early flights of waterfowl, but it first really became evident during mid-April warbler fallouts. As it turns out, these weren’t the earliest-ever dates for species like Black-throated Greens, but they were certainly earlier than the last few years. By the end of April, the bulk of early May arrivals, even the cuckoos, were already back. By May 10, almost all species had shown up, and ten days after that it was over. NFC numbers in the second half of May were far down from last year, while the first night movers showed up again just after the Fourth of July.
The first half of July was rife with boisterous molt-migrants, and I expected that, given overall warming trends, the week-ahead trend would vanish. But it never did, with species after species peaking in numbers well ahead of last year, all the way until today. Towhees normally peak between today and October 8, but there were far more of them, though I had no time for a thorough count, at the end of September. Only the 11-day deluge drew numbers and departure times out, but as soon as that ended, the holdovers pushing totals up fled en masse.
Paralleling early departures are the early arrivals. A trickle of Dark-eyed Juncos showed up in September, and their high counts are already tripping the eBird numbers filter. The first Fox Sparrow is calling. And, as the light grows enough to see, the sweet song of a Purple Finch becomes clearer and better pronounced. One is perched resolutely in the apple tree, among the sparrows, a mere ten feet above the ground, facing the dawn glow of Sapsucker Ridge. Over and over it sings until finally flying away, pinging. Later I glimpse a few more flying along Sapsucker, and hear their flight calls as well. Checking the records, I see that these are the earliest-ever Purple Finches for Plummer’s Hollow. Can Evening Grosbeaks be far behind?
The Flight to End All Flights
If the deluge solidified Plummer’s Hollow’s status as a migrant trap, a sort of landlubber’s Presque Isle for the goldenrod-and-aster crowd, its denouement was easily foretold. By the morning of October 2, Lincoln’s Sparrow, typically a scarce species, was the most common sparrow in the field, far outnumbering even white-throats. Yellowthroats still erupted at every bend of the trail, and with a little pishing, appeared in agitated groups of four or five. Even fall-only Connecticut Warblers were bottled up, and my high of three probably reflected total numbers of this cryptic species of up to ten at a time in the hotspot.
Reports of sunlight and a strange cerulean tone to the sky began to filter in by early afternoon, and the evening looked like this:
I double-checked the antenna to make sure I wouldn’t miss what was surely going to be an epic night. Then, while driving up the road at 5:30 AM, a text from Eric was a screenshot of BirdCast - “5,898,400 birds have crossed Blair County so far tonight (est.).” This was followed, unfortunately, by a note about the generator. Apparently the power had gone out in the night. Murphy’s Law in the flesh. When I got to garage, the power was back on, so I could only hope that a few hours were grabbed at any rate. At 6 AM, that latest-ever whip-poor-will called in the distance, overlapping with a Great Horned Owl. A few hundred Swainson’s and some Gray-cheeks rained down as the towhees woke up. With the sunlight breaking through the fog, a fallout of Brown Thrashers became evident, though I could only confidently tally three.
Eventually I found the time to go over the tape. Though BirdCast said lift off started by sunset, the first flight calls were hidden by the noise of the dusk. At 7:17 PM, the last local White-throated Sparrows ceasedtheir incessant yammering. Twelve minutes of utter silence ensued, and then the first zeep warbler went over at 7:29. Zeeps and other warbler flight calls increased in volume until peaking around 9 PM, something I’ve never seen before. This confirmed the 9 PM peak that BirdCast reported. While warblers and a few others such as Indigo Buntings and Chipping Sparrows dominated the higher registers, the lower kilohertz bands were clogged with thrushes. Wood Thrushes were extraordinarily frequent for this late in the season (in the following days, very few were left), and most of the rest were Swainson’s, Gray-cheeks, a growing number of Hermits, and perhaps a handful of late Veeries. Rose-breasted Grosbeaks were predictably constant. Perhaps the biggest surprise to me was the scores of Green Herons. I’ll need to go over the recording again, but the only semi-rarity I could clearly ID was a Greater Yellowlegs. Not longer after ten, the recording stopped when the electricity went out, but by then, the bulk of the swarm had passed over.
The above is a two-minute sample from 8:43 PM with about 120 vocalizations, the vast majority Swainson’s Thrushes and a fairly high number of Wood Thrushes, with other identifiable species (from the sonogram) such as Ovenbird and Cape May Warbler.
This one is a 90-second clip from 8:53 PM with around 21 Green Heron skewchs, a Greater Yellowlegs 4-note pew series, some unidentified low trills, and a variety of common thrushes and others.
Overall, the two-hour period from 7:30 to 9:30 averaged 1 NFC/second, an extraordinarily high sustained number only surpassed by the 5 to 10 NFCs per second during pre-dawn peaks of fall Swainson’s Thrush and Veery descents. If we estimate that the antenna picked up an average of 2 calls/bird going over, that’s a detection rate of 30 individuals a minute, or around 3,600 for the two-hour period. Generously, perhaps, we can guess that the antenna is detecting calls up to 1,000 feet up, within a radius of 750 feet.
We can refer to BirdCast’s data for that night for an idea of how this fits into the big picture, and whether the aging antenna is up to the job. Slightly over 6 million birds passed over Blair County during the course of the night (6:50 PM - 7:10 AM) with a peak of over 1.4 million in the air at once around 9 PM. They came from the north-northwest at the beginning of the evening, but after 7:30 directly from the north. The average flight speed was 21 mph at the height of it, though that decreased markedly during the night, while the average height above the ground was 1,600 feet.
A crude estimate based on Blair’s area of 527 square miles gives us about 2,700 individuals above each square mile of surface at a time; the antenna appears to detect around 6% of the area of a square mile —perhaps 40 acres. That’s around 160 total birds within the range of detectability at any given time, without factoring in altitude. Beyond that, we are left in the dark, as we don’t know what percent of the birds are members of species that don’t emit NFCs, nor how often NFCs are emitted among the night callers, nor whether all or only some individuals in a given flock vocalize, and on and on. We’re not really not even sure exactly why some species call and some don’t, and the reasons for doing so.
I remain unable to visualize what the bird cloud looks like as it passes over, though I suppose it might not be too different from diurnal movements. My main consolation these last few nights is finally figuring out where to stand and which way to face at exactly the right time to actually see a few of the last night fliers in the twilight’s first gleaming. I’ve gotten to where I can pick out a few blacker specks from the blackness, dark meteors visible for a split second overhead. Previously, in the inky black neck of the field, I would only listen as thrushes rushed by, some dropping into nearby trees and repeatedly vocalizing, others falling slightly farther to the south. Try as I might, though, I could never actually see them.
And so as it all winds down, I look forward to the first frost to quell the insect noise. My goal this year is to keep the antenna going until next year, if I can do it without the computer freezing. I’m curious what goes over in the dead of winter, and the fact that I missed a chance at Horned Grebes last January, and probably Snow Geese, still rankles me.
/The Vanishing/
While most species exited gracefully and gradually this fall, the Icterids just up and split. The last Common Grackles showed up August 13. The last Red-winged Blackbirds were on August 15. In 2023, both species lingered well into the fall. Brown-headed Cowbirds left the hotspot in July, and only reappeared at the end of September. I presume that all three species went off, literally, in search of greener pastures, but it was certainly odd to go for more than a month without a sign of them around the mountain or above the balcony.
