Birds of prey are found increasingly in captive situations. When sick, these animals show only very subtle signs of disease, making the detection of disease difficult. For this reason, the analysis of hematologic parameters is a very useful technique for the avian veterinarian. However, birds are most frequently transported to the veterinary clinic for a health check-up. This study investigates the effects of transport-related stress on heterophil and lymphocyte morphology and hematologic parameters of peregrine falcons (Falco peregrinus) and Harris's hawks (Parabuteo unicinctus). Twelve birds of each species, all adults, mixed males and females, were analyzed. Each group of 12 was comprised of 6 trained (accustomed to being transported) and 6 untrained birds. Samples of blood were taken from all birds in their place of origin and again 1 week later after 1 hour (35 km) of transport. Both samples were taken in similar conditions (eg, time of day, duration after feeding, environmental temperature, sample handling) so that any variation would be caused only by transport-related factors. Both untrained groups showed a significant (P < .05) increase in the heterophil/lymphocyte ratio (H/L). Whereas untrained peregrines showed no other significant change, untrained Harris's hawks had a significant leukopenia, lymphopenia, and eosinopenia. Trained Harris's hawks showed a significant monocytosis, whereas trained peregrines showed no significant change. Transport had no apparent influence on heterophil or lymphocyte morphology. Although the difference between pre- and posttransport was significant in some parameters, all values in the 4 groups remained within the reference ranges for the species. Therefore, we can conclude that 1-hour transport for trained or untrained members of these 2 species to a clinic need not be factor that requires the clinician's consideration when interpreting a hematologic sample. However, the 2 species reacted differently to transport. Further studies on other species are suggested. The H/L ratio is proposed as the most sensitive measure of stress response in the blood picture of raptors, and possible uses are suggested.