Friday, May 17, 2013

Fri-D: Dowitchers

In New Jersey, in May, they're ALL Short-billed Dowitchers.

Now I know that's an exageration, but only by a whisker, and yet there have been a high number of reports of Long-billed Dowitcher this spring. Having NEVER seen a Long-billed Dowitcher (LBDO) in May in NJ, I have to ask myself, is there something wrong with me? Do I have a disease preventing me from seeing LBDO, or worse, do I not know what a LBDO looks like or sounds like? One must consider one's failings, so I thought, who can I ask for help? How about Michael O'Brien, Richard Crossley and Kevin Karlson, authors of The Shorebird Guide, NJ residents, and friends of mine? If anyone knows what's up with LBDO in spring, it's them. So I asked them to answer the following question:

In May in New Jersey, are Long-billed Dowitchers:

a) Annual in small numbers, such that an experienced birder can expect to find one or two each year with a strong effort?
b)Annual in very small numbers, such that an experienced birder might miss them in some years despite a strong effort?
c) Very rare and probably not annual, often missed by experienced birders?
d) Your answer. . . .

Michael answered, "I would say B is probably closest to accurate, which would give them about the same status as Curlew Sandpiper. They may seem a bit rarer than that, but are certainly less likely to be detected than Curlew Sand."

Richard answered, "As far as the coastal marshes go, I would say c. I have not birded Forsythe enough in Spring to really know what the status is there but I don't recollect teams getting it in the bird race. I did see a report from last week of a few (4?) at your place and wondered about the record - did you see them?"

And Kevin answered, "(B) is the answer here. LBDO is often hard to find in spring, with hendersoni SBDO often mistaken for LBDO, even by "experienced" birders."

So there you go. My own answer hovers between super rare in May and something rarer than that, so between B and C. I have seen LBDO in March and April, after milder winters when a few wintering LBDO's might survive and still be around. But not yet in May. However, I concede that better birders than I have found LBDO in May in NJ, but not bloody often, as Richard would say.

Kevin kindly provided the below image, of a Long-billed Dowitcher on the left and a hendersoni race Short-billed (the latter taken at Heislerville, NJ this week) on the right, so ask yourself, can I really tell these two apart?



Much is made of the structural differences between the two species, and they are real. Long-billed has been characterized as looking like it swallowed a grapefruit, i.e. rounded with a higher back and deeper belly compared to Short-billed's slimmer look. Here's the thing, though: Most Short-billed Dowitchers fly up to NJ from points far south, and arrive skinny. They then feed like crazy and before departure can look so fat you'd think they'd have to walk to Canada to nest, there is no way they could fly as fat as they are. So it is completely possible to be at, say, Heislerville, and see a skinny dowitcher next to a fat dowitcher, and both of them will be Short-billed, as will the thousands around them.

Kevin was kind enough to provide the following details on i.d.ing the two: "I have attached a shot of a LBDO look-alike (breeding hendersoni SBDO) that Jonathan Meyrav and I saw at Heislerville on May 10 [this is the bird in the right photo, above]. It is very similar to LBDO, but differs by its short bill with blunt tip and slight kink near the tip; by the very broad orange and white feather edges on the back feathers; and by the spots rather than strong bars on the upper flanks, lower flanks and vent. The body shape is rounded on this bird because it has been feeding heavily and is fully nourished, but the weight balance is more evenly balanced in front of and behind the legs, and it does not show a chest-heavy weight distribution with broad shoulders and thick neck that is typical of LBDO. The bill of this SBDO has a comparatively deep base compared to LBDO's shallower based bill with a more slender overall shape and flatter tip. This bird would probably be called a LBDO by a good number of birders, even experienced ones. Thanks for bringing this topic up, Don."

So there you have it from the experts. Be careful, stay within your abilities. And you can always use voice: "keek" for LBDO and a rippling "tu-tu-tu-tu" for Short-billed.

Or you can simply go with the notion that in May, in NJ, they're all Short-billed Dowitchers.

4 comments:

  1. Unquestionably between 'b' and 'c'... which was why a report of 30+ LBDO ay Heislerville earlier this year by an "experienced" birder stunned me...

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