With regard to the record of Bell's Sparrow, I believe that I saw and photographed the canescens subspecies of Bell's Sparrow at the Thrasher Spot in Arizona. Bell's Sparrow includes belli and canescens. Belli has a dark grey head, thick malar stripe and no (or sometimes very little indistinct) streaking on the back while canescens has little streaking on the back and a malar strip that is intermediate in width between the very thin malar strip of Sagebrush Sparrow (nevadensis) and the thick malar strip of belli. In general, canescens is intermediate between belli and Sagebrush Sparrow. I have used the excellent summary article about field marks, http://phainopeplafables.com/2013/08/14/sage-sparrow/ by David Vander Pluym, which points out that the width of the malar strip may be the best field mark to distinguish the two new Sage Sparrow species, Bell's and Sagebush, as well as the canescens subspecies. See also Neil Hayward's discussion on his Accidental Big Year Blog. Below I include photos of what I believe are Bell's Sparrows, the canescens subspecies with the rationale included in the captions.
Bells Sparrow (canescens) very little to no streaking on back, intermediate width malar stripe |
Bell's Sparrow (canescens) same bird as above, slightly different view |
Bell's Sparrow (belli or canescens?) apparent thicker malar stripe may be caused by the angle of viewing, light and shadows, unstreaked back
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Bell's Sparrow (belli or canescens?) same bird as immediately above, note difference in appearance of malar stripe |
Bell's Sparrow (canescens?) |
Bell's Sparrow (canescens?) same bird as immediately above notice how angle of viewing and light affects the appearance of malar strip |
There is no change in my total species list reported in my post, Clean Sweep in Arizona.
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