ML192420441

Age

Not specified

Sex

Not specified

Media notes

photo by Brian Taber

Observation details

Descriptive Details The bird flushed to our vehicle’s left from the sand/small gravel cross-dike road edge. Three characteristics readily differentiated it from the numerous Savannah Sparrows, and occasional Song Sparrows, we had been flushing in similar fashion throughout the day. It was larger, more gray than brown, and it had a long tail with white tips on the outer retricies. When it landed ~30 meters away it remained briefly stationary in the open in small vegetation, then retreated into the weeds and began preening. As photos were being taken the following plumage details were agreed to by all four observers; dark bill, very distinct black malar stripe; yellow iris; pale tan/white throat, breast, belly and flanks with heavy black streaking, noting that the flanks were noticeably buffy; long dark gray tail and dark legs. After preening for about 5 minutes, the thrasher began to actively pursue and feed on insects. It made quick runs along the road’s edge directly toward then past the vehicle, approaching as close as 3 meters. Its behavior was typical thrasher/road runner-like, head and tail horizontal as it ran. When it paused, its posture was erect. We saw some tail bobbing, and on a couple of occasions it did wing-flicking similar to Northern Mockingbird behavior. Because the thrasher was so close, fine details of the head and neck were easily observed and documented. Just below the eye was a proportionately large, square, brown patch. Below that patch was a small white rectangle. The primaries and secondaries were dark brown/black with very thin outer edges. No vocalizations were heard. All agreed this was a Sage Thrasher. Elimination of other species This thrasher’s predominately gray/brown color, facial markings, white tips on the outer rectricies and relatively smaller size ruled out Brown Thrasher. Long-billed Thrasher, like Brown Thrasher, is rufous brown above, with brighter white background to the dark-streaked breast, belly and flanks. That species lacks white tips on the outer rectricies. Absence of white at the base of the primaries, white on rectricies confined to feather tips, brown tail rather than black, and bright yellow eye ruled out juvenile Northern Mockingbird. Bahama Mockingbird shares many of the same field marks as Sage Thrasher. However, its breast and belly are plain, unstreaked; fine, dark streaking is confined to the lower flanks on Bahama Mockingbird. American Pipit was ruled out by this thrasher’s relative size, yellow eye color, extensive, heavy breast, flank, and belly streaking and white tips on the outer rectricies. This bird exhibited no jerky head movement when in motion. Rock Wren, documented at this facility 4 Nov 1990-17 Mar 1991 (Rottenborn & Brinkley 2007), was ruled out by this thrasher’s relative size, yellow eye color, extensive, heavy breast, flank and belly streaking and white tips on the outer rectricies. Rock Wren outer rectricies tips are tan. photos by Bill Williams (061), Dave Youker (431), Brian Taber (441)

Technical information

Model

COOLPIX L830

ISO

125

Focal length

136 mm

Flash

Flash did not fire, auto

f-stop

f/5.9

Shutter speed

1/800 sec

Dimensions

3456 pixels x 3456 pixels

Original file size

2.47 MB