Status and Breeding Ecology of the Arizona Grasshopper Sparrow

Research Task: 8327CNG.9.0
Task Manager: Janet Ruth

The Arizona Grasshopper Sparrow (Ammodramus savannarum ammolegus) is a disjunct race that breeds in desert grasslands of southeastern Arizona, extreme southwestern New Mexico, and adjacent parts of northern Sonora and Chihuahua, Mexico. This subspecies was only recently documented as breeding in the Animas Valley of New Mexico. Partners in Flight and the U.S. Fish and Wildlife Service both consider it a species of conservation concern for desert grassland habitats. Concerns regarding this subspecies focus on the apparent extreme fluctuations in a relatively small breeding population, the effects of habitat loss due to suburban development, and limited information about its breeding ecology and the effects of habitat modification due to management practices such as fire and intensive grazing. This task will provide valuable information to managers by addressing the following research needs identified in the Partners in Flight Bird Conservation Plans for Arizona and New Mexico: (1) determine the causes of decline in Arizona Grasshopper Sparrows in the Animas and Playas Valleys and survey for more populations in the “boot heel” of New Mexico; (2) determine the bird's home range and breeding territory size (Arizona); and (3) determine if the species is a source or sink population (Arizona). The initial phase of this research involved the repetition of historical roadside breeding-bird surveys of abundance and distribution that were conducted in 1982 and 1987 in order to compare abundance and distribution over this time period. These comparisons showed that the Sonoita and San Rafael Valleys in Arizona and the Animas Valley in New Mexico continue to support the primary population centers for this subspecies. An increasing pattern in number of singing males was documented from 1982–1987 from the historical surveys, and a subsequent decline in numbers was seen from 1987 to 2004–2005. Small populations remain in other grassland valleys in southeastern Arizona.

 For more information contact Janet Ruth

Related Products

Publications

• Distribution of breeding Arizona Grasshopper Sparrow (ammodramus savannarum ammolegus) in the southwestern United States: Past, present, and future
• Molt and aging criteria for four North American grassland passerines
• Preface [Birds of the US-Mexico borderlands: distribution, ecology and conservation]
• Birds of the US-Mexico borderlands: distribution, ecology and conservation