ML490037671
יוצר
תאריך
מיקום
- גיל
- לא מוגדר
- זוויג
- לא מוגדר
פרטי השורה
This is the same bird that I saw on 9/30/22. I heard it call several times using its’ "keek-keek” notes, when a few people came down toward the water. None of the photos in this posting have been altered (photo shopped) or cropped. I am going to share my reasons why I ID'd this dowitcher as a long-billed instead of a short-billed. Some of my information comes from two different guides- "The Sibley Guide to Birds" written and illustrated by David Allen Sibley & "The Shorebird Guide" written by Michael O'Brien, Richard Crossley and Kevin Karlson. I recommend both of these guides to have in your own collection. On pages 190 & 191 of The Sibley Guide it lists the months for 3 different plumages. Both species list juvenile plumage from (Jul-Nov), adult nonbreeding plumage from (Sep-Apr) & adult breeding plumage from (Apr-Aug). These are important dates for dowitchers that come through VT in the late summer/early fall. It appears that the adult birds that arrive here in Sept. are already in nonbreeding plumage. The juveniles however don't seem to transition into nonbreeding plumage until Nov. Now, on page 438 of The Shorebird Guide it shows fall migration of long-billed dowitchers as happening between early July and Dec. Females leaving in mid July & males leaving two weeks later. They begin to arrive along the Atlantic and Gulf coasts by mid-July, with peak numbers of adults between early Aug. and early Sep. On the Atlantic Coast, juveniles first appear by mid-Sept. and peak in Oct. So, during the months of (Sep.-Nov.) the first thing that I try to determine is whether the dowitcher I am looking at is an adult or a juvenile bird. It's actually very easy to tell because in both species, the adult nonbreeding birds are mostly gray, sort of bland and pretty much nondescript. The juveniles however are quite colorful. If I see an adult nonbreeding bird I am not able to tell which dowitcher it is unless I hear it. If I hear a keek-keek call note then I ID it as a long-billed. If I hear more of a tu-tu-tu type of call notes then I ID it as a short-billed. Now, if it shows coloration other than plain gray, I usually decide that it is a juvenile bird. I am careful to realize that there could be an adult bird that is late to transition into its' nonbreeding plumage but I/myself have yet to see one of those in VT during the fall migration (Sep-Nov), but one can't rule it out. Others, perhaps have seen one or more. To separate a juv. long-billed from a juv. short-billed is relatively easy. A juv. short-billed Atlantic bird (see pg. 191 in The Sibley Guide) is quite colorful. It shows a buffy breast and buffy colored fringes on the scapulars, tertials and internal markings of the tertials. Tertials are a third set of feathers that are closest to the body. The first two sets of wing feathers are the primaries and secondaries. When a dowitchers wings are folded the tertials can be seen closest to the tip of the tail and they are quite long. There are usually 3 that are visible. Some birders might think that they are looking at the primaries but the primaries are actually hidden underneath the tertials. Scapulars (see pgs. 463 & 464 in The Shorebird Guide) are defined as "relatively large feathers covering the base of the upper wing. On a standing bird these feathers generally cover the largest portion of the upperparts". There are upper scapulars and lower scapulars. Just below the lower scapulars are coverts. A juv. long-billed bird (see page 190 in The Sibley Guide) is less colorful than a short-billed but is not all gray colored like a nonbreeding adult. It shows dark scapulars surrounded by rusty/reddish colored fringes. The tertials are dark gray and have no internal markings and sometimes show a rusty/reddish fringe around them. So, what I do to ID which juv. dowitcher I am looking at is look for two and only two specific field marks. The first one is to determine the color of the tertial and/or scapular feather fringes. The second one is to determine whether or not the tertials have internal markings (vertical or horizontal). If the above mentioned feather fringes are buffy colored and there are visible internal markings in the tertials then it is a SHORT-BILLED DOWITCHER. If the above mentioned feather fringes are rusty/reddish colored and there are no internal markings in the tertials then it is a LONG-BILLED DOWITCHER. Note: In order to see the rusty/reddish colored above mentioned feather fringes "really well", the dowitcher's back must be positioned at an angle where the sunlight is shining on it directly (when the sun is out). The bird in this report does show the rusty/reddish colored fringes of the scapulars as well as a few of the tertials and does not show any internal markings in the tertials. See photos below for confirmation. I hope this very long written bit of info is helpful to others that may be having difficulty figuring out which dowitcher they are looking at.
מידע טכני
- מודל
- Canon PowerShot SX60 HS
- ISO
- 100
- אורך מוקד
- 247 mm
- פלאש
- Flash did not fire
- צמצם
- f/6.5
- מהירות תריס
- 1/200 sec
- מימדים
- 4608 pixels x 3456 pixels
- גודל קובץ מקורי
- 5.18 MB