Abstract
The Arizona Field Ornithologists (AZFO) is attempting to compile comprehensive, current, and accurate lists of the bird species found in all of Arizona’s 15 counties. In 2017, the Coconino list was posted on the AZFO website. Now, the Pinal County list is available (AZFO 2018), which also notes the species that have bred in the county. These well-researched lists can help birders and field ornithologists know the birds they may encounter in each county and if their observations are unusual. Moreover, they contribute to the natural history of each county, which can be useful to future researchers. Determining that a particular species of bird has been recorded and has bred in Pinal County is not always clear-cut. This article describes the particular characteristics of the county and the process entailed in finding and deciding whether species should be included in the checklist or not.