Yesterday afternoon I found 2 Long-billed Dowitchers, with 1 Short-billed Dowitcher at the Dead Creek/Otter Creek Confluence west of Vergennes. To follow up on Don Jones' email about dowitcher identification, I agree they are a major challenge. For the bird we observed at Whitney Creek, I had been leaning heavily toward Short-billed based on visual features, and when I finally heard the definitive call of a Long-billed I was a bit surprised.
The birds from yesterday at the confluence were significantly easier, but it was still a challenge. I spotted the 3 birds foraging together almost as soon as I got there, and my initial impressions were that of Long-billeds. I soon got my audio recorder from my car, and set up my microphone pointed at the birds in hopes of capturing vocalizations, and went back to studying them. I judged all 3 to be juveniles, and as I studied each individual more closely, I realized that 1 was definitely a Short-billed, showing a light buffy breast and prominent buffy markings in the scapulars and tertials, and could also see a distinct but slight downward bend to the tip of the bill. Eventually, I heard a single "tu-tu-tu" call, further confirmation on short-billed. Were they all short-billeds? I went back to studying the other 2 birds, and realized that they were possibly molting into adult nonbreeding plumage. This made the ID a bit more challenging. These birds seemed to have straighter bills, and solid gray across the chest. The scapulars and tertials were predominantly black with thin rufous fringing. They also seemed to have more of a hunched-backed appearance, but this character kept changing with position, and I wasn't sure after the Whitney Creek Long-billed that appeared mostly flat-backed to me when I had viewed it. They also gave me the impression of being slightly larger than the SBDO. I also got great looks at the tails when birds preened, which seemed to show a lot of white. About an hour and 20 minutes into the viewing, I got the clincher, a single "keek" call, characteristic of Long-billed. Then soon after, the 3 birds took flight, and I heard several more "keek" calls and a twittery series of "keek" calls, and captured a decent recording of it. So at least 1 Long-billed was present, and I'd be pretty confident in saying the 2 were both Long-billeds.
If the birds stick around it's a good chance to see both species side by side, and an easier ID since all 3 were likely juveniles.