Hematologic parameters and hemoparasites of nonmigratory Canada geese (Branta canadensis) from Greensboro, North Carolina, USA.

Abstract

Large flocks of wild, nonmigratory Canada geese (Branta canadensis) have established permanent residence throughout the eastern United States and have become a public concern. Few studies have assessed the hematologic parameters for these populations, which could provide useful information for monitoring individual and population health of Canada geese. This study measured the hematologic parameters and detected the presence of hemoparasites from 146 wild, nonmigratory Canada geese in central North Carolina, USA, during their annual molt. The age class, sex, and weight of each bird were recorded at capture. Values for packed cell volume (PCV), estimated white blood cell count, white blood cell differentials, and heterophil: lymphocyte ratios were calculated for each bird. Adults and female geese had higher estimated white blood cell counts compared with juveniles and males, respectively. The PCV increased with weight and age class. Adult geese had higher percentages of heterophils and heterophil: lymphocyte ratios, whereas juvenile geese had higher percentages of lymphocytes. Relative eosinophil counts in adults increased with decreasing bird weight, and relative monocyte counts in juveniles increased with increasing weight. Three percent of geese were infected with species of Hemoproteus blood parasites. Atypical lymphocyte morphology, including pseudopods, split nuclei, and cytoplasmic granules, was observed in 5% of the birds. The hematologic values reported for adult and juvenile nonmigratory Canada geese in this study may serve as reference intervals for ecological studies and veterinary care of wild and captive Canada geese.