However, it wasn’t too long after the bird’s discovery that the Sharp-tailed Sparrow had been officially split into two distinct species, the Nelson’s Sharp-tailed Sparrow and the Saltmarsh Sharp-tailed Sparrow; and there was a limited amount of information available describing how to separate these two similar-looking species.
An article in the April 2001 edition of ABA's "Birding" magazine titled "Song of the Sharp-tail" helped point out most of the differences between the two, but the photos of the Lake Minsi bird showed some characteristics of both.
Here in PA, Nelson’s Sharp-taileds are found annually in very small numbers, usually on the grassy islands found in the lower Susquehanna River during the month of October. They breed in the north-central U.S. and Canada and their migration path sometimes sends them through PA. The Saltmarsh Sharp-tailed, on the other hand, is strictly a coastal bird, very rarely straying inland. Mainly because the Nelson’s was the most likely of the two to be found in PA, it was generally agreed that the bird was probably a Nelson’s. One of the photos was sent to the Pennsylvania Ornithological Records Committee (PORC), which eventually determined that Saltmarsh Sharp-tailed could not definitely be ruled out. It turned out that the committee’s hesitance to initially accept the record as a Nelson’s was the correct determination after all.
A few years later, Rick Wiltraut was looking at a specimen of a Saltmarsh Sharp-tailed Sparrow and a photo of the Lake Minsi bird. Something didn't look right to him, especially the bill shape and the streaking on the back. He began to wonder if the Lake Minsi bird might actually be a Saltmarsh Sharp-tailed Sparrow. He called several people about his concerns, including me.
Since only one PA record of Saltmarsh Sharp-tailed Sparrow existed, I decided to try and get some expert opinions by using a computer list service called “ID Frontiers” that deals solely with bird identification challenges. I scanned all of the available photos into my computer and sent them out with all of the other details that I recalled about the sighting. The very next day, I got a response from Jim Rising, the author of the guide, “The Sparrows of the United States and Canada”. He wrote:
“If those pictures were taken along the coast, I don't think that we would hesitate to call the bird a Saltmarsh----and I am pretty confident that that is what it is. The bill does look OK to me to be Saltmarsh, although a bit small. Why don't you send the photos to Jon Greenlaw. He knows these birds better than I, especially the coastal ones. I'd be really curious to hear what he thinks, and what others think as well. Please do keep me posted. There is one specimen of a Saltmarsh from western PA, identified by Kenneth Parkes, in the Carnegie Museum, I think. I don't know of any other inland records. Let me know if you know of some. Thanks for sending these, and keep me posted about your decision, if you will.”
I quickly got a response from Jon Greenlaw of the Archbold Biological Station in Venus, Florida, stating:
“There is little doubt that your bird is a bona fide Saltmarsh Sharp-tailed Sparrow. It is indeed unusual for this species to appear inland away from the coast. In this case, easternmost Pennsylvania near the New Jersey border is not very far from the New Jersey and Delaware Bay coasts. Your photo documentation of Saltmarsh STSP should be archived somewhere for future reference. The usual course is to submit your observations as a report to your state bird records committee and let them verify identification for purposes of converting your report to a state record.”
He continued by writing:
“All visible plumage and morphological (bill) characters in the photos fall within range of variation of Saltmarsh STSP. The combination of strong contrastiness between orange ochre malars and buffy breast, and strongly developed, relatively discrete streaking across the breast and down the sides and flanks confirm the ID. The dull (versus bright white) scapular streaks help to discount 'n. nelsoni.' The bill length is on the short side, as Jim Rising pointed out, but seems to fall within the range of variation found in Saltmarsh STSP.”
He also made some very interesting comments on some of the questions I had asked him:
(1) Yes, nominate Nelson's STSP can be boldly marked below, but it is distinguished by other features, notably strongly-patterned dorsum, little malar-breast contrast, and a small bill.
(2) The head profile (rounded versus flattened) has been oversold as a
character. The position of crown feathers is subject to the bird's
motivational state. There may be an "average" appearance, but that
is not helpful for critical ID's of individuals.
(3) Throat whiteness is variable in both species and most subspecies.
There often is a wash of buffy on the throat of Saltmarsh STs, but in
other cases, the throat can be quite white.
(4) Contrast between breast color and the white abdomen is not useful; it
depends much on wear. The buffy color on the breast is bright in
fresh-plumaged birds, but very dull and pale in worn birds. Your bird
is a fresh-plumaged bird, so you should expect some contrast.
(5) The dark markings around the eye is individual variation; no species-
specific significance.
(6) Discreteness of dark streaking on underparts also will depend to some extent on wear. In fresh-plumaged STs, streaks in Saltmarsh STs typically appear blurred along the edges; this is caused by some pale barb tips. Later, as feathers age and barb tips disappear, the streaks "harden", or become more strongly discrete.
(7) Grayish sides of the neck not species-specific in Saltmarsh STs.
Applying this great information to the photos made things a lot clearer.
Over the next few weeks, I received several other responses from ‘top-notch’ birders who also verified that the bird was indeed a Saltmarsh. So, thanks to Rick’s inquisitiveness and the photographic documentation, a previously questionable record became a 3rd Pennsylvania state record and one of the few inland records for the entire East Coast! Obviously, this was a new state and county bird for me. A special thanks goes out to Jim Rising and Jon Greenlaw, whose expertise confirmed this rare record.
No comments:
Post a Comment