Technical Abstract: Terrestrial wild birds commonly associated with poultry farms have the potential to contribute to the spread of H5N1 highly pathogenic avian influenza virus within or between poultry facilities or between domesticated and wild bird populations. This potential, however, varies between species and is dependent on several virus and host factors, including habitat utilization, susceptibility, and viral shedding patterns. To provide “field-relevant” data on susceptibility and shedding patterns of house sparrows (Passer domesticus) and rock pigeons (Columba livia), we inoculated 20 birds from each species with decreasing concentrations of A/whooper swan/Mongolia/244/05 (H5N1) highly pathogenic avian influenza virus and evaluated the birds for morbidity, mortality, viral shedding, and seroconversion over a 14-day trial. The house sparrows were highly susceptible to the H5N1 highly pathogenic avian influenza virus as evidenced by low infectious and lethal viral doses. Additionally, house sparrows excreted virus via the oropharynx and cloaca for several days prior to the onset of clinical signs. Based on these results, house sparrows could play a role in the dissemination of H5N1 highly pathogenic avian influenza in poultry. In contrast, pigeons were resistant to the highly pathogenic avian influenza virus, requiring a high concentration of virus to produce infection or death. When infection did occur, the duration of viral shedding was brief and viral titers were low. These data suggest that pigeons would contribute little to the transmission and spread of H5N1 highly pathogenic avian influenza virus in poultry.