Over 350 species of birds make up the order Psittaciformes; many of these are maintained in captive environments. Malnutrition is commonly diagnosed in captive psittacine birds; therefore, providing nutritionally adequate diets must be a primary concern. This review integrates quantitative information on the dietary habits and nutritional requirements of psittacine birds to facilitate the formulation and evaluation of diets for birds in captivity. Initially, characterization of the diet and feeding strategy of a particular species in the wild can provide insight into appropriate diet choices in captivity. Knowledge of the gastrointestinal anatomy and physiology can be used to elucidate the capacity of that species to utilize various feedstuffs. For example, the presence of a highly muscularized gizzard may allow a bird to utilize a seed-based diet, whereas a species possessing a small gizzard may be unable to process such a diet. Finally, nutrient requirements determined in a particular species or a related species (eg, similar digestive physiology and feeding strategy) may be applied to create a nutritionally adequate diet. Understanding the factors involved in selecting appropriate diets enables aviculturists, veterinarians, and nutritionists to maintain and propagate these birds with increased success.

Infection by Chlamydophila psittaci (formerly Chlamydia psittaci) is a common cause of morbidity and mortality in companion psittacine birds and is transmissible to humans. Replication of Chlamydophila is inhibited by plasma doxycycline concentrations greater than 1 μg/ml, but prolonged treatment periods of 30–45 days are needed to eliminate infection. Medication of birds for this prolonged period is difficult with current treatment methods. In this study, drinking water medicated with doxycycline hyclate at 800 mg/L was provided ad libitum to healthy African grey parrots (Psittacus erithacus timneh) and Goffin's cockatoos (Cacatua goffini) for 42 days. Blood samples for doxycycline analysis were collected on treatment days 4, 7, 14, 21, 28, 35, and 42. Mean doxycycline concentrations exceeded 1 μg/ml throughout the 42-day treatment period. In the African grey parrots, the mean doxycycline concentration (± SD) for all plasma samples collected during the study was 1.51 ± 0.68 μg/ml and doxycycline concentrations were greater than 1 μg/ml in 73% of the samples. In the Goffin's cockatoos, the overall mean was 2.78 ± 1.00 μg/ml and doxycycline concentrations exceeded 1 μg/ml in all samples. No adverse effects were noted in the African grey parrots. All of the 8 treated Goffin's cockatoos were physically healthy, but changes in plasma biochemical analyses suggested mild hepatic damage in 3 birds. Results of plasma biochemical analyses in these cockatoos were within reference ranges when retested 7 days after doxycycline treatment ended. The results of this study suggest that doxycycline-medicated water can safely maintain plasma concentrations adequate for treating avian Chlamydophila infections in African grey parrots and Goffin's cockatoos housed under standardized conditions.

“Megabacteriosis” is a condition affecting many psittacine and nonpsittacine birds for which an effective, reliable therapy and means of prevention have not been developed. Megabacteriosis has been associated with a chronic wasting condition in the budgerigar (Melopsittacus undulatus) termed “going light,” but the organism also has been detected in clinically healthy, thriving birds. In this study, removing eggs from the nests of megabacteria-positive adult budgerigars and hand-raising hatchlings under isolation conditions prevented transmission of megabacteria in all offspring. Staining fecal smears and histologic tissues with Calcofluor White-M2R also was shown to be a reliable means of demonstrating megabacteria. Hand-raising budgerigar hatchlings, and those of other avian species in which megabacteriosis is considered to be of concern, is a potentially valuable method of producing offspring that are free of this organism.

This study determined the occurrence and identity of chewing lice (Mallophaga) on 35 clinically healthy raptors presented with traumatic injuries at the California Raptor Center during the summers of 1993 and 1994. Samples of lice were collected and preserved in 70% ethanol during physical examinations within 24 hours of admission. Eleven species of chewing lice were collected and identified from 7 species of raptors, including 2 long-term captive birds. All louse species except 1 were on their usual, previously documented raptor hosts. Four of the 10 species of free-living birds examined had no lice, but their sample sizes were small (1–3 birds each). At least 1 bird from each of the other 6 raptor species harbored some lice, but only 2 species, an American kestrel (Falco sparverius) and a barn owl (Tyto alba) were sampled in useful numbers. One of 8 kestrels yielded lice (1 species), and 4 of 14 barn owls were infested with lice (representing 2 species). Two captive birds, a spotted owl (Strix occidentalis) and a Swainson's hawk (Buteo swainsoni), were infested with lice (1 species each) after 463 days and 1198 days in captivity, respectively.

A unique case of primary pulmonary leiomyosarcoma was diagnosed postmortem in an adult white Carneau pigeon (Columba livia) that had presented with respiratory distress, lethargy, and anorexia nonresponsive to antibiotic treatment. Histologically, the pulmonary mass was composed of multiple interlacing bands of malignant spindle cells. Prominent eosinophilic staining of these cells with Masson trichrome stain and immunohistochemical staining that was positive for actin and desmin confirms smooth muscle origin. This is the first report of a primary pulmonary leiomyosarcoma in a pigeon.

Hemochromatosis was diagnosed at postmortem examination of 5 birds, representing 3 species of lories, including 2 Duyvenbode's lories (Chalcopsitta duivenbodei), 2 black lories (Chalcopsitta atra), and 1 rainbow lory (Trichoglossus haematodus). All 5 birds were housed in the same zoological collection and were fed the same commercially available lory nectar. Classic histopathologic lesions, consistent with hemochromatosis, were observed in all 5 birds. Increased iron concentrations were detected in the nectar diet (1450 ppm) and in the sample of liver (3500–7600 ppm) of affected birds.

A red-tailed hawk (Buteo jamaicensis) was presented with a right midshaft compression fracture of the humerus. The fracture was partially healed, but with significant loss in bone length. This report describes a technique for harvesting autogenous callus, which was utilized with tie-in fixation to reconstruct architecture to repair a cortical defect. This procedure restored the functional length of the humerus.