Introduction

Botteri's Sparrow, Hereford, AZ, 12 August.

Figure 1. Known breeding range of Botteri’s Sparrow.

The Botteri’s Sparrow is a predominantly Mexican species that reaches the northernmost extreme of its distribution in southeastern Arizona and southern Texas. A tall-grass specialist with plain brown plumage and evasive ground behavior, it reveals itself by its conspicuous song, the cadence of which sounds like a ping-pong ball coming to rest. This species was first described by Philip Lutley Sclater (1857) in the Proceedings of the Zoological Society of London as Zonotrichia botterii. The type specimen was taken in Mexico by Dalmatian naturalist and collector Matteo Botteri (Mearns and Mearns 1992). Because of its elusiveness and geographically restricted range in the United States, this sparrow was not studied in depth until recently.

Two distinct populations of Botteri’s Sparrow inhabit the United States. The subspecies P. b. arizonae breeds in small, isolated colonies in semidesert grassland, especially stands of giant sacaton (Sporobolus wrightii) grass and oak (Quercus) woodland in southeastern Arizona and northwestern Mexico. P. b. texana breeds in coastal prairie with scattered shrubs along a narrow strip of the Gulf Coast of southern Texas and northeastern Mexico. Botteri’s Sparrow today is most abundant in pockets of healthy ungrazed or lightly grazed grasslands, historically fragmented by agricultural pressures. Because U.S. populations of this species are locally abundant, rebound from moderate habitat disturbances, and occupy a variety of grassland types, the species appears stable despite its restricted range.

This account draws most heavily on a three-year study (1981–1983) of the distribution, habitat, and breeding biology of an P. b. arizonae population centered at the Appleton-Whittell Audubon Research Ranch Sanctuary in southeastern Arizona (Webb 1985). The only recent field study of P. b. texana was undertaken from 1984 to 1985 at Laguna Atascosa National Wildlife Refuge in southern Texas to assess the population status of that subspecies (Marshall and Clapp 1985).