I was doing a raptor behavior survey when I heard a faint "tsip" note from across the road, about twenty to thirty meters away. Without any raptors to observe, I welcomed the distraction of a song bird to watch for a little bit.
Across the road at the barbed wire fence, were two small sparrows. I glimpsed them through my binoculars, and realized they were not my usual sparrow suspects. So I used the scope to get an even better view. They then hopped along the road, and into the nearby roadside weeds and barbed wire, and one of them foraged around the culvert a few meters from me. I was able to get very good, long looks at the birds. And since my initial looks were of a bird that I was not sure of the identification, I studied the birds long and hard to note all the field marks in my head before they moved on.
With sparrows, it is especially important to note as much detail as possible. With all my birdwatching experience, I used all my skills and knowledge of the sparrows I knew to note as much as I could, in as much detail as I could. I also knew what particulars I should make note of: tail length and any white present, head & bill shape, head patterns (crown especially), and what kind of breast pattern, if any.
The overall color of the birds was orangish, more commonly referred to as ochraceous. Not a gray bird, and not brown. More of a dark peachy color. This was true all over the bird. The bill was on the small end of the scale for a sparrow. The face had ochraceous cheeks, not gray or brown. As the bird moved, the wind ruffled the feathers on the head, and a distinct crown stripe was seen, a more intense orangish color than the rest of the head, enough to show a distinctive stripe. On the chin, it had double moustachial stripes, both brownish, not really black. The head shape was slightly flatheaded in my views of the bird.
The belly of the bird was white. While the breast of the bird, and down the sides or flanks, fine streaking was seen on a yellowish-orange background. In the middle of the breast was a slightly larger streak, not quite a spot like in the Song or Fox Sparrows, but a distinctly larger streak.
The tail was short, for a sparrow. And no white was seen on it. The overall bird size was on the small end of the sparrow spectrum.
Eventually, the birds moved out of view. And I noted all the details I could recall. Then, when my survey was done, I consulted my field guide in the truck. And then when I returned to home, I consulted the other field guides we had there. Conveniently, all birds I see now, including migrants, should have their adult plumage; some juvenile sparrows may have streaking, but since it is early December, the juvenile plumage should be gone by now.
There are 49 species of "bunting" sparrows that are commonly seen in the United States and Canada. I already have a strong idea about what bird I have seen, at least to genus, but to be sure, I go through the elimination process. Especially since I suspect it is a bird I haven't seen before, at least recently.
It's not a longspur (4). It's not a towhee (6), Olive Sparrow (1), or seedeater (1). It's not a junco (2), or any of the buntings (3). I can eliminate the genus of Aimophila sparrows, none have streaking (6). I can eliminate the Zonotrichia sparrows, for all are too large for my bird (this genus includes the White-crowned Sparrow, for idea of what a "large" sparrow is).
I eliminate the following: Lark Sparrow (wrong head pattern, size, even juvenile); Sage Sparrow (range, color); Black-throated Sparrow (size, face patterns), Five-striped Sparrow (range, color pattern), Black-chinned Sparrow (range, color); American Tree Sparrow (size, unstreaked breast); Chipping Sparrow (unstreaked breast); Field Sparrow (bill color, unstreaked breast); Brewer's Sparrow (range, unstreaked breast); Swamp Sparrow (unstreaked breast, head colors); and the Fox and Song Sparrows (size alone, streaking too bold on them).
This leaves the Ammodramus genus (7 birds), the Savannah Sparrow, Lincoln's Sparrow, and Vesper Sparrow. Because of the head shape (flat-headed look), I suspect it's the Ammodramus genus, and I check the individual's left that are not in that genus. The Vesper Sparrow has bold white outer tail feathers, so that's out. Lincoln's Sparrow has the right streakiness across the breast, the right body shape. The head looks wrong, though - it has the wrong colors on the side. My bird was yellow-orange throughout the head and body, and the Lincoln's Sparrow has a gray head. So I'll eliminate it, but I will still consider it if I don't have a better match. I was in the right habitat, after all.
Savannah Sparrow. Hmmm...much can be right. Habitat ok, head might be close; there are a lot of variations in the Savannah Sparrow for color. However, all the variations show very strong breast streaking, coarser and more extensive than what my bird had. So, no to Savannah Sparrow. Which leaves the Ammodramus genus, a difficult genus to identify birds from, since rarely are good looks gotten at the birds in the field. It's December, so though the bird may not breed here, or winter here, it may be migrating through. So range may not help.
Range does eliminate the following individuals. Saltmarsh Sparrow (A. caudacutus) and Seaside Sparrow (A. maritimus). Nelson's Sparrow, the interior form, does not have distinctive streaking, so no to that species. Le Conte's Sparrow has a WHITE crown stripe and streaking confined to the sides. That leaves Henslows, Grasshopper, and Baird's Sparrows, with the possibility of returning to Lincoln's Sparrow too.
The distinct band of streaking across the breast eliminated the Grasshopper Sparrow. Henslow's and Baird's Sparrows look similar in the field guide, so I read descriptions. Henslow's has "...with large, pale bill; finely striped across breast. Striped olive-colored head in conjunction with reddish wings help identify it. Also note double moustache stripes and spots behind 'ear'." Baird's, however, is described as "Light breast crossed by narrow band of fine black streaks. head ocher-buff; streaked. Key mark is broad ocher median crown stripe. Double moustache stripes. Flat head."
Um, yeah, so that confirms it, and is what I suspected in the field since the bird didn't look familiar! Also, Baird's is more likely then Henslow's based on migration route. My location is a little east for Bairds, but far west for Henslows, based on locations of breeding and winter ranges.
And that is how I came to get my species number 422 for North America, Baird's Sparrow. I had only seen this bird once before, in Mexico in 1997. This bird was probably still in migration to the Mexican Plateau.
This also illustrates the importance of noting as much detail as possible when watching a bird. Had I tried to consult a field guide while the bird was available for view, I would have lost the opportunity to study the bird as long as I did, and I might have missed that all important ocher crown stripe.