Emaciated raptors are frequently encountered in wildlife medicine and rehabilitation, yet there is little published data detailing the biochemical criteria for diagnosing metabolic abnormalities associated with emaciation, and even less on guidelines for correcting them. The concept of refeeding syndrome, which has been documented in humans and some domestic species, is frequently discussed amongst wildlife veterinary and rehabilitation professionals, but has never been documented in an avian species. The goals of this study are three-fold: (1) to document values for common biochemical markers of starvation in healthy, wild red-tailed hawks (Buteo jamaicensis), (2) to identify biochemical markers of starvation in emaciated red-tailed hawks presenting to the Swanson Wildlife Hospital and (3) to evaluate the effects of two methods of nutritional therapy on these biochemical markers in order to explore the concept of refeeding syndrome and monitor response to nutritional therapy in this species. This study has been divided into two phases, with Phase 1 involving the sampling of healthy migrating red-tailed hawks in collaboration with Braddock Bay Raptor Research in Honeoye Falls, NY. Phase 2 will investigate nutritional recovery of hospitalized emaciated raptors at the Janet L. Swanson Wildlife Hospital in Ithaca, NY. We will evaluate markers of starvation (packed cell volume (PCV), β-hydroxybutyrate, albumin, and amino acid profile), and monitor analytes that are typically deranged in classical refeeding syndrome (phosphorous, magnesium, potassium) in hawks assigned to one of two refeeding plans. Group one will be fed a whole prey diet at 100% of the maintenance energy requirement (MER) for the duration of the study. Group two will be refed gradually, starting with an elemental diet below MER, and slowly reintroduced to a whole prey (mouse) diet. This data will serve to inform the veterinary and wildlife rehabilitation communities about markers of starvation in both healthy and emaciated hawks, the presence or absence of refeeding syndrome in an avian species, and the effects of commonly employed nutritional therapy on the metabolic status of a frequently encountered raptor species.