Abstract

Twenty free-ranging spectacled eiders (Somateria fischeri) and 11 free-ranging king eiders (Somateria spectabilis) were anesthetized with propofol for the surgical implantation of satellite transmitters. For analgesia, bupivacaine at 2–10 mg/kg was infused into the incision site and ketoprofen at 2–5 mg/kg was given intramuscularly at the time of surgery. Four of 10 male spectacled eiders and five of six male king eiders died 1–4 days after surgery. None of 10 female spectacled eiders and only one of five female king eiders died during the same post-operative period. None of 20 female common eiders (Somateria mollissima) anesthetized with propofol, bupivacaine, and propofol and none of 20 female common eiders anesthetized with isoflurane and given ketoprofen (2–5 mg/kg) died within 4 days of release. Significant histopathologic findings from two dead male king eiders were severe renal tubular necrosis, acute rhabdomyolysis, and mild visceral gout. Gross necropsy findings in three additional dead male king eiders were consistent with visceral gout. Propofol has been used as an anesthetic in other avian species without problem, and it is unlikely that it is unsafe to use in male eiders. We strongly suspect that the perioperative use of ketoprofen caused lethal renal damage, but bupivacaine toxicity or cumulative toxicity of ketoprofen and bupivacaine may also have occurred. Male eiders may have been more susceptible to renal damage than females because of behavioral differences they exhibit during their short stay on land. The combination of propofol, bupivacaine, and ketoprofen should not be used to anesthetize free-ranging male eiders. Propofol alone or isoflurane should be used. The perioperative use of non-steroidal anti-inflammatory drugs should be avoided in any bird that may be predisposed to renal insufficiency.