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The American Ornithologists’ Union recently separated Sage Sparrow into two species: Bell’s Sparrow (Artemisiospiza belli) and Sagebrush Sparrow (Artemisiospiza nevadensis). The two new taxa winter across the Mojave and Sonoran Deserts, with a general geographic pattern of Bell’s Sparrows to the west and Sagebrush Sparrows to the east. But the two taxa have overlapping wintering ranges, with western Arizona and southeastern California the ground zero of this overlap.
The two taxa are difficult to separate in the field and more than a few field ornithologists have commented that it is impossible to tell the two apart. To make matters more complex, the ‘Mojave’ subspecies of Bell’s Sparrow (Artemisiospiza belli canescens) is the one that both most resembles the Sagebrush Sparrow and which is most likely to overlap geographically with wintering A. nevadensis.
However, in addition to size (Sagebrush Sparrows are larger on average than Bell’s), field ornithologists have noted apparent plumage differences between the two new species. An excellent summary can be found here.
Arizona Field Ornithologists has generously provided Point Blue Conservation Science (formerly PRBO) with funding to study Sagebrush and Bell’s sparrow identification and distribution in southwestern Arizona in the winter of 2014. The goal is to capture and photograph Sagebrush and Bell’s Sparrows at sites in Maricopa, Yuma, La Paz, and Mohave Counties from February 4 – February 16 to provide insight into field identification and distribution in the region.
Organizers are currently recruiting volunteers to assist with mist netting (herding birds toward nets and installing and moving nets). They are also very interested in hearing from you on sites to capture Sagebrush and Bell’s Sparrows, for while they have a number of potential sites in mind, it is always helpful to have more from which to choose.
The tentative schedule is below, and they will select final sites by the end of January 2014:
- Maricopa County sites: February 4-9
- Yuma and La Paz Counties: February 9-12
- La Paz and Mohave Counties: February 13-16
If you are interested in helping, please contact Chris McCreedy.