On 29 April 2002, the Ryan wildfire swept through 38,000 acres of the Sonoita Valley in southeastern Arizona. This fire offers a valuable opportunity to conduct post-fire research to determine the effects of such a substantial wildfire on wintering grassland birds and the structure and composition of the grasslands on which they rely. The opportunity is particularly valuable because three years (1999-2001) of avian and vegetation data exist for this upland grassland habitat prior to the fire, with which post-fire data can be compared. The pre-fire data were collected as part of a larger study on wintering habitat used by grassland birds in southeastern Arizona. This study will provide information about the biological effects of wildland fire in grassland ecosystems, specifically about how wildfires affect vegetative structure and composition and wintering grassland bird abundance and habitat use. It will assist managers in addressing locally important information needs about how wildland fire affects wintering grassland birds of conservation concern and the distribution of invasive exotics such as Lehmann lovegrass. In order to ensure the comparability of pre-fire and post-fire data, the same plots and methods used in the previous study will be used again for this project. The post-fire study will involve all of the plots located on the Audubon Appleton-Whittell Research Ranch (burned) and Davis Pasture of the BLM Las Cienegas RCA (unburned), for purposes of comparison. Bird communities will be surveyed using a combination of mist netting and transect surveys. Standard vegetation composition and structure measures will be used to characterize the grassland habitat.