Determination of hematologic reference intervals for free-living King vultures (Sarcoramphus papa)

As obligate scavengers, New World vultures (Cathartiformes: Cathartidae) play a key role in carcass removal and disease control. Associated with this ecosystem service, vultures are exposed to the consumption of harmful substances such as poisons, heavy metals, antibiotics, or non-steroidal anti-inflammatory drugs. Monitoring the health status of vulture populations is a priority and an important conservation strategy, and hematologic analysis is a practical and effective method that can be useful for this purpose.

Report hematologic reference intervals in free-living King vultures (Sarcoramphus papa), one of the least studied New World vulture species.

Red blood cell concentration, packed cell volume, hemoglobin (Hb) concentration, MCV, MCH, MCHC, WBC concentration, differential count and absolute WBC concentration, heterophil to lymphocyte ratio, and total protein concentration were determined. We used a non-parametric method to calculate the reference intervals. In addition, we compared our results with the hematologic measurands reported for the Black vulture (Coragyps atratus), the Andean condor (Vultur gryphus) and the California condor (Gymnogyps californianus).

With the exception of Hb, monocyte, basophil, and eosinophil concentrations, the mean hematologic measurands observed in the King vulture were similar to those recorded for the other New World vulture species, and the heterophil to lymphocyte ratio was lower in the King vulture compared to the Black vulture.

In this study, we have reported for the first time the hematologic reference intervals in a free-living population of King vultures in Costa Rica. Future research should consider comparison among free-living New World vulture species.