ML479554541
Contributor
Date
Location
- Age
- Not specified
- Sex
- Not specified
- Sounds
- Song
- Playback
- Not specified
Media notes
Natural song by a continuing Bendire's Thrasher recorded by Curtis A. Marantz on 2 April 2022 along the western edge of Clark Dry Lake, Anza-Borrego Desert State Park, San Diego County, California. This bird had been present since initially reported on 23 March 2022 by Dave and Gwen Dorn. Natural song given by a bird that was perched atop a large mesquite tree along the western edge of the dry lake
Observation details
We heard the singing thrasher immediately upon our arrival at the stand of scattered mesquite trees along the southwestern edge of the dry lake. Over the next 20 minutes or so I recorded the singing bird without looking at it carefully, but after the sun rose, we tried getting photos and I studied the bird more carefully through my scope. This bird’s typical behavior pattern was to alternate singing from the mesquites with dropping to the ground, presumably to forage. I further noted that the thrasher would typically begin by singing from deep withinside a given mesquite before eventually moving to the top and singing from a more exposed perch. In addition to the complex, warbled song that it gave consistently, albeit in relatively short bouts before moving to another tree or drooping to the ground, I also heard a short “wheer” and an even softer “churk,” both of which I think were given by the thrasher. Not unexpectedly, this bird sang more consistently before sunrise, and much less so later in the morning, but it did sing more intermittently even relatively late in the morning. This was a medium-sized passerine with the distinctive shape of a thrasher despite its not having an overly long bill. I noted that the medium-length bill would have extended backward on the face to a point near the rear edge of the auriculars, which is at the shorter end of the spectrum for a western thrasher. Further apparent was that the bill was relatively slim throughout its length, and with the culmen weakly yet smoothly decurved from the base to the blunt tip; however, the lower edge of the lower mandible was only very subtly curved and generally appearing nearly straight. The forehead was sloping and the crown was rounded with a weak peak that appeared to be above and behind the eye. This bird’s head was of unremarkable size for a thrasher, the neck was short and inconspicuous, and the body was plump, full-chested, and with a posture when this bird perched atop a mesquite to sing that was not quite as upright as diagonal with the tail held downward in the plane of the body. The wings were short, with the wingtips reaching right about to the tips of the uppertail coverts, but also with a primary projection that was only about a third the length of the exposed secondaries, and the tips of four primaries evident beyond the longest secondary in a notably rounded wingtip. The tail was both long and relatively slim. My impression was that the tail was comparable in length to the head, neck, and body combined. The tail was generally held closed, when it was parallel-sided and relatively slim, but I did notice that the outer feathers were about 10% shorter than the central feathers. The tips of the central rectrices were broadly rounded, but they were also noticeably worn (as were the wingtips to a lesser degree). In flight, the bird held the tail straight backward, when it again appeared conspicuously long and slim throughout its length. Also apparent on the flying bird was that the wings were rounded. The legs or feet appeared to be relatively stout, but not unusually so for a thrasher. This was a subtly marked bird that was a light, sandy-brown overall. The head, neck, and upperparts were a warm, sandy-brown to buffy-brown throughout. I noted no markings on the forehead, crown, or upperparts. I saw only at times a subtly darker wedge in the lores between the base of the bill and the eye, suggesting that it may have reflected shading and not plumage coloration. The supraloral, superciliary, and auricular regions were unmarked and the same color as the forehead and crown. Demarcating the lower part of the face was a cream colored submoustachial-stripe that showed only moderate contrast with the darker moustachial-region, and a somewhat darker malar-stripe that was thin and relatively inconspicuous. The throat, from the chin down to its junction with the breast, was cream-colored to whitish and unmarked, and thus appearing similar to the submoustachial stripe. I further thought a little white extended onto the uppermost part of the breast in the center, but the breast also showed at least some buff in the center. The sides of the breast contrasted as more deeply buff and thus more colorful than the center and flanks. The flanks were conspicuously washed with buff. Further apparent were dusky brown markings across the breast, these extended to some degree onto the upper belly and the flanks. The markings on the breast represented small, but well-defined, triangles or possibly chevrons, but on the upper belly and flanks they were more diffuse and with a more irregular shape. The lower belly was again whitish and unmarked. My views of the undertail coverts were not very good, but what I did see appeared to be short, rounded, and deeply buff in coloration. The underside of the tail was mostly quite dark, but with narrow, yet well-defined, tips of whitish on at least the outermost pair (and possibly the two outermost pairs) of feathers. My impression was that the white tips on the outer feathers extended roughly straight across the inner web, but I thought the paler coloration extended inward at least some distance along the outer web. Returning to the upperparts, the crown, neck, and back were all about the same shade of warm, sandy-brown with no markings. This same color also appeared to extend down through the rump, but at times the uppertail coverts appeared slightly darker, though this may have reflected shading rather than plumage pigmentation. The upperside of the tail was an even darker shade of brown, with most feathers brown to their tips; however, when the tail was spread slightly, I could see the narrow tips of whitish on at least the outermost pair. The whitish tips were sharply demarcated, and relatively narrow, but I was unsure about their precise shape. The wings were about the same shade of sandy-brown as the back. On the median coverts the sandy-brown bases contrasted with narrow tips of whitish to produce a subtle, and somewhat interrupted, upper-wingbar. The greater coverts similarly colored, with the feathers mostly about the same shade of medium-brown as the upperparts, but with the outer three or so feathers again having narrowly whitish fringes that appeared to extend straight across the tips of the feathers without extending up along the edges. The result was a short and somewhat jagged bar across the outer edge of closed wing just in from the shoulder. I looked for, but never really saw the primary coverts, and the one larger feathers along the edge of thy wing, which was presumably either the alula or one of the associated feathers, was uniformly dark brown. The remiges appeared to contrast dark brown centers with paler edges to the outer webs that were similar in color to the back, which resulted in a subtly striped pattern that was similar on the primaries and secondaries, but which did not appear to include the innermost secondaries. The exposed primary tips were somewhat darker than the rest of the wing, but also lacking obviously paler fringes. The overall impression of the wing was an overall color not unlike that of the back, but with subtle fringes on both the greater and median coverts that were most conspicuous as whitish tips to the median coverts, on which there was a moderately conspicuous wingbar. The bill appeared to be slate-gray to dull blackish in its entirety. I looked for a pale base to the lower mandible, yet failed to see this even though I could see that the cutting edge of the lower mandible was yellow basally, and as such, it was similar in color to the mouth linings that were evident when this bird sang. The black pupil contrasted sharply with irides that were a bright yellow with a subtle orange cast. The legs and toes appeared to differ in color depending on the list, at times appearing dull black but at others they seemed to be more of a dark, horn-brown.
Technical information
- Recorder
- Nagra ARES-BB+
- Microphone
- Sennheiser MKH-20
- Accessories
- Roché 30” fiberglass parabola
- Original file size
- 60.78 MB