Maricopa Audubon Society Birds in Maricopa County
 
 

Arizona Special Species: BOTTERI’S SPARROW

By Jim Burns

Skulking, as is their wont, at the bottom of Arizona’s multifarious bag of special species, species found only here or more easily here than in any other state, is a handful of sparrows, at once the most underappreciated and most challenging of all our state’s bird families.  Botteri’s, Aimophila botterii, probably the species most underappreciated and most challenging of all, is also the one most closely associated with Arizona's late summer monsoon season.

The center of Botteri’s breeding range is central Mexico where it is widespread.  It breeds locally south to northern Costa Rica and locally north to southern Arizona where it is a short distance migrant, withdrawing in September south into Mexico, reappearing in late April.  “Reappear” is used quite loosely here for, in fact, in most years there is little evidence this grassland inhabitant has returned until summer rains trigger its territorial and nesting instincts, advertised by singing from exposed high perches, typically the tops of ocotillo or mesquite.

A ground nester which forages exclusively on the ground for insects in summer, weed seeds in winter, Botteri’s is almost literally never seen unless singing.  Its bouncing ball song, accelerating as it dribbles down the vocal scale, is so distinctive that seekers seldom study the bird’s plumage carefully for the beautiful but subtle field marks which distinguish it from its grassland neighbors and Aimophila congeners, Cassin’s, Rufous-winged, and Rufous-crowned.

The latter three utilize more and broader ecological niches than Botteri’s which has a relatively narrow preference for the arid, open desert grassland with scattered shrubs which was heavily overrun by the state’s cattle industry beginning in the late 19th century.  It should come as no surprise, then, that Botteri’s is much harder to find now than then and much harder to find than its three Arizona congeners.  The small, non-migratory population of Botteri’s in south Texas uses coastal prairie, also historically overgrazed, and the species is declining there.

The best strategy for finding Botteri’s in Arizona is to wait until the summer rains have commenced, then park near or very slowly drive through proper habitat between sunup and mid-morning, windows rolled down, listening for the song which you will recognize from having previously listened to a tape.  The best and most easily accessed area may be below Madera Canyon between Florida Wash and Proctor Road where the highway passes through experimental rangeland.  Try Forest Service 406, dirt/cobble, which makes a big loop southwest from the main road there.

Other spots where we have seen and heard Botteri’s are the rest area just west of Sonoita along state route 82, Gardner Canyon north of Sonoita west of state route 83, the Nogales airport, the junction of Arivaca Road and state route 286 on the Buenos Aires National Wildlife Refuge, and along Hereford and Moson Roads between the San Pedro River and the east flanks of the Huachucas.  In exchange for this information you must promise to actually find a singing Botteri’s with your binoculars and study its plumage carefully with the sun directly behind you.

Close looks in good light give the lie to traditional field guides which dismiss the subtle differences between Botteri’s and Cassin’s by saying the two species cannot be reliably distinguished except by voice.  Though Texas birds are grayer, Arizona’s Botteri’s are warm, suffused, and rusty compared with the cold, contrasty, and gray Cassin’s.  Botteri’s has a curved culmen (upper half of the bill) and unstreaked flanks.  Cassin’s culmen is straight, its flanks streaked.

Non-birders without binoculars can stumble upon the splashy species such as trogons and hummingbirds. If you append “birder” to your name you must accept the sparrow challenge and Botteri’s, a strong vocalizer in season, is a good place to start in Arizona.  Check out the cryptic perfection of the central tail feathers and the subtle way the uppertail coverts mimic the upper back pattern.  Then go find a skylarking Cassin’s and repeat the exercise.  The differences are fascinating, the recognition rewarding.

The Botteri’s shown here was photographed in July, 1998.  I had heard it shortly after sunup, then followed my ear to the top of its ocotillo.  For the next three hours I entered the bird’s world, shooting discreetly as it gleaned breakfast under bushes, interacted with its mate, and periodically interrupted foraging to proclaim from a favored singing post.  I did not observe copulation or a nest, but figured it was just a matter of time.

By 9:00 a.m. when the bird flew into a mesquite directly above me, I had flattered myself thinking it accepted me as part of its environment, just another grazing ungulate.  As I shifted the lens to celebrate this proximity, I caught movement in the corner of my eye.  Twenty yards out a bull, quite obviously a bull, was shambling directly toward me!  I was sure I was hallucinating in the heat and humidity.  The Botteri’s was oblivious and began announcing his boundaries to all the world.  Calculating the height of the lowest mesquite branch, I decided I too would be oblivious for another ten yards and turned back to the viewfinder.  This seemed like a good day to die, as good a way as any committed bird photographer could choose.

At ten yards the huge beast veered away, curiosity inexplicably assuaged.  This hair-raising event gave new meaning to the term “sparrow challenge,” brought an adrenaline rush few birders ever get from the sparrow family, and engendered greater appreciation for all the vagaries of Botteri’s 20th century grassland habitat.

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Last Updated: January 7, 2018 14:16     Copyright © 2018 Maricopa Audubon. All Rights Reserved