Vermont Rare Bird Reports 2020

Ted Murin is credited below under "Verbal Narrative..." as the likely original finder of this bird.

Strong winds from WSW, temperature in the mid-70s F. Mix of clouds and sun. Bird observed mostly in cloud-diffused sunlight. Sun orientation was behind observer, so the bird was always viewed under excellent illumination conditions without backlighting.

Scope: Nikon Fieldscope (30X)
Binoculars: Nikon Monarch 5 (8x40)

No previous field experience with Sharp-tailed Sandpiper. Extensive field experience with Pectoral Sandpiper, the most similar species common to North America.

Lake Champlain sandbars and mudflats, between Colchester Causeway and Law Island.

Feeding on exposed sandbars - straightforward probing with bill in sand; not "sewing machine" motion like a dowitcher. Always on the sand, never wading. In flight, fast direct flight with sharply pointed wings. Not "fluttery" or rapidly shifting directions. Flight was low, remaining no more than 2-3 feet above the sand or water while I was observing. The bird was not interacting with other birds that I could tell. Part of the time it was near some Pectoral Sandpipers, but it flew in and flew away independently of the PESAs. I never saw this bird with any PESA in the same scope view, therefore all of my comparisons are indirect. No interaction with observer as I remained on the Causeway and did not attempt to wade out onto the sandbar.

None observed.

First, giving credit where it is due: On Sunday 8/2 I was contacted by Ted Murin, who had briefly seen a brightly colored shorebird at the Causeway that he thought could be a Sharp-tailed. With this as inspiration, I visited the Causeway on Monday 8/3, arriving at 8:30 AM at the site where most of the shorebirds have been seen recently. Several other birders were there already, but they unfortunately had all left before I saw "the" bird. It was very windy.

At about 9:30 AM "the" bird flew into my binoculars field of view and landed on a sandbar. The bird had an obvious and striking, bright buffy color on the breast that immediately drew my attention. I was able to get my scope on it quickly and view it for less than a minute before it flew off and I lost it. At about 9:45 AM I relocated the bird with my scope, on another sandbar near some Pectoral Sandpipers. I watched it for 2-3 minutes before it flew away to the north. I was able to follow the bird in flight with my scope for perhaps 10-15 seconds before I lost it again. Then I had to leave.

This was a medium-sized shorebird, similar in size and overall body structure to nearby Pectoral Sandpipers. My first impression of the bird was that it seemed "plump", but this was not based on any direct comparisons with PESAs. Indeed the strong wind may have affected birds' posture while feeding on the sand, which would make subtle structural differences difficult to assess.

The bird's head had a rusty brown cap. The face had a strong white supercilium bordered by the cap above and by a warm brown eyeline and cheek patch below. The supercilium appeared wider behind the eye than in front of it. The nape was warm brown and the throat was whitish. The overall face/head pattern was bolder on this bird than on nearby PESAs.

The legs were dull yellow in color. The bill was dark in color, perhaps a bit paler near the base, and very slightly decurved. The bill appeared shorter in proportion to the head size than the bills of nearby Pectoral Sandpipers.

The upperparts of the bird appeared brighter than those of the nearby PESAs. With the wings folded, rufous and buffy edges stood out more prominently on tertials, greater coverts, scapulars.

Seen only in flight. The central portion of the rump and uppertail coverts were dark in color, while the sides appeared white with black streaking.

In flight, wings were sharply pointed and seemed long in proportion to body size. The upper surface of the wing was mostly dark gray in color, perhaps slightly darker on the primary coverts. There was only a faint, thin wing stripe. The primaries and outer secondaries lacked any paler trailing edge. The underwing pattern was not seen well.

A bright buffy color covered the whole breast. This showed prominently (and eye-catchingly) on the bird, both on the ground and in flight. Streaking on the breast was confined to a narrow band of faint streaks across the upper breast. The rest of the breast had the bright buffy color but no streaks. Flanks and undertail coverts were not seen well.

Seen in flight, the tail was short and wedge-shaped. (How "sharp" it was, I could not tell!)

Other "medium-sized" shorebirds such as Stilt, Curlew, Ruff, and Dunlin, as well as both Yellowlegs and both Dowitchers, were easily eliminated by differences in body structure, bill shape, and many other field marks. The relevant similar species to consider is Pectoral Sandpiper. I believe that PESA is eliminated based on the following field marks: (1) Bright buffy breast with faint streaks confined to a thin band on the upper breast; buffy remainder of breast without streaks. This pattern is difficult to reconcile with any plumage of PESA that I have seen or know of. PESA characteristically has a heavily streaked breast lacking bright buffy color, and with the streaks sharply cut off across the belly. (2) Distinct head pattern with rusty brown cap and supercilium that widens behind the eye. Again this is a strong field mark for STSA, not for PESA. (3) Brighter overall plumage on tertials, greater coverts, scapulars than observed in PESA. (4) Shorter bill proportional to head size than in PESA. (5) Side uppertail coverts and rump were white with dark streaks. (Expect cleaner white with no dark streaks in PESA.) The combined field marks of this bird that I have tried to convey, and the comparisons that I made (albeit indirectly) with PESA in the field, are consistent with a juvenile Sharp-tailed Sandpaper and not with Pectoral Sandpiper.

The bird was a juvenile based on clearly seen features of the plumage. And I understand that this is shocking based on communications from Paul Lehman, who points out that Aug. 3 is an extremely early date for juvenile STSA to migrate or occur as vagrant, especially in the eastern U.S. Still, I don't see any easy way to make the field marks fit a different species or age. But I am open to suggestions.