Musophagiformes

The family Musophagidae is made up of the group of birds called turacos, including plantain-eaters and go-away birds. They are naturally found in the sub-Saharan region of Africa occupying the forest, woodland, and savanna regions. Previously, turacos had been placed in the order Cuculiformes, but evidence led to placing them in their own order Musophagiformes.^9,15 They were associated with cuckoos because of a particular anatomic feature, that is, zygodactyl toes, in which digits 2 and 3 face forward and digits 1 and 4 face backward, although digit four is flexible and may face toward the back or the front. Other than the toe arrangement, no other commonalities between cuckoos and turacos exist.^21,22

The family Musophagidae is divided into six genera (Turaco, Ruwenzorornis, Musophaga, Corythaixoides, Crinifer, and Corythaeola), which contain 23 species and 38 subspecies. Others have divided the turacos under a suborder Musophagae, which is further subdivided into three groups of Corythaeolinae (1 species Corythaeola), Criniferinae (5 species Corythaixoides and Crinifer), and Musophaginae (17 species Tauraco, Ruwenzorornis, Musophaga).²²

Turacos are long-lived, medium- to large-sized birds, ranging in body weight from 200 to 400 grams (g) with the great blue turaco weighing up to and over 1 kilogram (kg). They have long tails, conspicuous head crests, stout beaks, and colorful feathering. Most species of turacos have unique pigments in their feathers: turacoverdin, a true green pigment found only in these birds, and turacin, a true red pigment. These pigments are copper based and not made from carotenoids as in other bird species. This pigmentation specialty in turacos has been well described.^9,22 During handling, the feathers may exfoliate easily as a defense mechanism. Turacos are sexually monomorphic, with the exception of the white-bellied go-away bird, in this species the female's beak is a dull green and the male's is black. Sexing may be done by feather or blood deoxyribonucleic acid (DNA) analysis or laparoscopic examination.^10,14 Turacos are arboreal, gregarious, active birds. They are poor flyers but are able to run in the trees and foliage quite well. Anatomically, turacos are similar to other bird species with the exception that they have little or no ceca, a distensible esophagus with no crop, a thick muscular proventriculus and a thin-walled ventriculus, a relatively larger liver for its body size, and a short intestinal tract.¹¹ Turacos regurgitate food when stressed or captured. It is important to allow this to occur so that the bird does not aspirate food particles.

Housing

Turacos are active birds and require space to move around. Flight cages or aviaries that are heavily planted seem to work best in providing perching, shelter, and hiding places. During the colder months, access to indoor housing, a shelter, or windbreak with a heat source is needed, as turacos are susceptible to hypothermia and frostbite. During the hotter months, these birds cool themselves by gular fluttering and sitting in the shade and enjoy bathing in a sprinkler or water bath. They may be housed with other species but may become territorial and aggressive toward others, especially birds of similar size. Caution must be taken, even with bonded pairs, that birds are not aggressive toward each other. Occasional separation of birds may be needed to inhibit an aggressive bird attacking its cage mate. Juveniles should be separated from the parents once they are able to feed themselves reliably.^3,20

Diet

The dietary requirements of turacos have not been well established. The family Musophagidae is generally vegetarian, tending more toward frugivory and folivory, but do occasionally supplement their diet with various small invertebrates, especially around breeding season.^12,18 Contrary to its name Musophagidae, turacos and plantain-eaters (Crinifer sp.) do not ingest bananas or plantains (Musa).²¹ In captivity, turacos have been fed various diet formulations. A good general diet should consist of a parrot pellet or soft-bill-type pellet with fruit mix and chopped greens, supplemented with a small amount of invertebrates and possibly a meat offering during breeding season. Corythaixoides, Crinifer, and Corythaeola species should be given more greens and leaf browse compared with other turaco species. Mixing the ingredients of the offered diet should help prevent specific item selection by the birds.^14,20

Restraint and Handling

Turacos are great runners on branches, which makes them hard to catch. They typically do not bite but will rake with sharp claws. They exfoliate feathers easily when held and sometimes will become overly stressed. Regurgitation of recently eaten food is also common. Inhalation anesthesia is more commonly used for advanced restraint and surgical procedures. It has been suggested that turacos be given time to calm down prior to exposure to isoflurane inhalant anesthesia because of issues caused by stress.^12,18,23

Physical Examination, Diagnostics, and Therapy

Examination of turacos may be done under manual or chemical restraint. A thorough examination should include assessment of plumage quality and skin condition, uropygeal gland evaluation, assessment of beak and cere (nares) quality, oral and choanal visualization, feet and nail check, cloaca check, ophthalmic visualization, otic review, auscultation of heart and lungs, coelomic palpation, musculoskeletal review, and assessment of body weight and condition. Blood may be collected from the right jugular vein for larger quantities and the wing vein for smaller samples.¹⁴ Clinical pathology data from three common turaco species are provided in Table 25-1. Fecal examination should be done on a regular basis. Turaco feces are typically moist and soft to loose. Familiarity with normal turaco feces is helpful when determining if the bird has dehydration, diarrhea, or enteritis. Direct wet mount examination should be done to visualize protozoans; centrifugation of a flotation solution for checking for parasitic ova; and culture if an enteric pathogen is suspected. Cytologic staining (with Romanovsky's type, Gram, or acid-fast stain) of fecal smears is helpful if enteritis is suspected. Additional testing (for Cryptosporidium and Giardia; viral culture; electron microscopy) may be applied, where deemed necessary. Medications used to treat turacos are similar to those reported for other avian species. Turacos may be individually identified by a leg bracelet or a transponder chip placed in the left pectoral muscle mass.

Shipment and Quarantine

Prior to shipping, a thorough examination should be performed to make sure that the bird is healthy and will survive the shipping process. Shipping containers should meet or exceed International Air Transport Association (IATA) regulations. The bird should be placed under 30-day quarantine once it arrives at the receiving institution. During this time, it should be introduced to the new diet and observed for behavior, eating, drinking, and eliminations. Testing should include multiple fecal examinations (2–4) and treatment if positive; complete physical examination; blood collection for complete blood cell count (CBC) and biochemistry; body weight; and confirmation of identification. Prophylactic treatment for parasites is sometimes done during the quarantine period.

Diseases

In general, turacos as a group appear to be fairly hardy birds but may be susceptible to diseases that affect other bird species. The Houston Zoo has housed over 1000 turacos of various species over the past 30 or more years. Review of the Houston Zoo antemortem and postmortem medical records and the literature has identified health problems that have affected this group of birds. Treatment is based on general avian medicine as no pharmacokinetic studies have been done in the Musophagidae. A basic summary of general causes of death in the Musophagidae collection at the Houston Zoo for the past 25 years (n = 193) has been listed in Table 25-2. This list reflects problems that may be found in the live birds of the collection that may be treated and is organized by age groups: perinatal and nestlings (0–30 days of age), fledglings and juvenile birds (1–11 months of age), and adults (1–28 years of age).

General health problems included aggression-induced trauma from cagemates and predators, leading to cuts, laceration, and possible death. Young birds are susceptible to dehydration and hypothermia, whereas older birds may present with issues of sepsis, amyloidosis, and unidentified diseases.

Digestive problems are common, ranging from Candida fungal infections, aerobic and anaerobic bacterial enteritis and sepsis⁷ leading to possible morbidity, regurgitation, diarrhea, intussusception, and possible rectal or cloacal prolapses.⁵ Foreign body ingestion or impaction from ingested materials with resulting intussusception has also been noted.²³ Hemosiderosis and issues related to iron storage in the liver have been previously documented in turacos,²³ although it does not seem to be common in the birds raised in the Houston Zoo. Endoparasites, including various nematodes and coccidia, as well as cryptosporidium protozoal infections, have been found in the Houston collection.*

Respiratory diseases vary widely, from tracheal obstruction, aspiration, and gaping (from parasites) causing dyspnea and distress to infections such as aspergillosis, bacterial sinusitis, and pneumonia.

Musculoskeletal problems may cause limping and lameness, and fractures may be found and repaired. Constriction by improperly fitting leg bands has occurred, and frostbite is possible from low temperatures. Rickets and rotational deformities may occur in young birds with inadequate diets.

Ectoparasites, broken feathers, broken nails, lacerations, bumble foot from inadequate perching, and rare skin masses have affected the integument.

Other miscellaneous diseases and medical issues include viral infections (avian influenza¹³), egg binding, ocular abnormalities (cataracts, corneal mineralization, trauma to the eyes or eye structures), otic issues (external ear infections), neurologic problems of unknown etiology (ataxia, head tilt), visceral gout, and hematologic issues (protozoan infections² and leukocytosis). Neoplasia seems to be rare in Musophagidae.

According to reports in the literature, captive turacos appear to be susceptible to mycobacterial infections.^3,17,24 At the Houston Zoo, 6 of 193 (3%) turaco deaths were attributed to Mycobacterium organisms. It seems that turacos may be susceptible to mycobacterial infection if exposed, but they do not appear to carry or harbor the bacterium any more than any other bird species.⁴

Reproduction

Turacos become sexually active in their second year. Courtship may include vocalizing, chasing, mutual feeding, flashing, billing, and wing spreads. Both sexes participate in building a large, usually flimsy, twig-and-stick nest in a tree or platform provided. Two to three eggs are laid and incubated by both sexes. If eggs are pulled when the hen is done laying the clutch, she will usually reclutch. Incubation periods vary among the species, ranging from approximately 16 to 31 days. When chicks hatch, they are semi-precocial with downy feathering and open eyes and are well developed. Both sexes feed the chick by regurgitation of food. Chicks will start to fledge at about 2 to 3 weeks of age, but the parents will continue to feed the young for several months thereafter. Occasionally, one adult will become aggressive toward the chick or its mate and needs to be separated from the enclosure. Chicks may be raised successfully by one parent. Turacos in captivity are generally very tolerant of nest monitoring and invasion by staff, which is important to chick survival. At the Houston Zoo, young chicks and eggs have been cross-fostered to other pairs of turacos (not necessarily the same species) that were sitting on eggs or pulled for hand-raising.²⁰ One pair accepted additional eggs after sitting for only 6 days on its own eggs.¹

Neonatology

Hatchling turaco chicks are active, gregarious birds. Attitude is one of the best monitoring tools for chick health. Turaco eggs hatch after an incubation ranging from as little as 16 to 18 days in Tauraco hartlaubi, 24 to 26 days in Musophaga rossae, and 29 to 31 days in Corythaeola cristata.²² Eggs may be parent incubated and raised, fostered to other turaco pairs of the same or different species, or artificially incubated and hand raised. Turaco pairs are generally tolerant of some nest invasion to check on chicks, remove for weighing, supplementation, or treatment. It is suggested that chicks be closely monitored for the first few weeks to make sure that they do not succumb to illness or parental neglect. Body weight loss is common in the first 1 to 3 days, but chicks should grow at a constant rate after that. Details on turaco rearing have been previously documented.^1,6

Chicks should be “bright-eyed,” aware of human presence, sometimes vocalize, or try to bite. They often gape to take food from anyone offering it. If a turaco chick is subdued or looks “sleepy-eyed,” a basic examination, weight evaluation, and diagnostics should be performed. Chicks are susceptible to digestive tract infections, so fecal cytology or swabs of the oral cavity, deep esophagus, and cloaca (if no feces available) should be evaluated for signs of fungal or bacterial overgrowth, particularly Candida or spore-forming bacteria. Other conditions that may arise include trauma from parents, parental neglect, poor doing, sepsis, and stunted growth of unknown etiology. Physical problems such as curled toes or rotated feet or legs should prompt evaluation of nest materials and positioning. Treatment for conditions that arise in turaco chicks is the same as that for other bird species.^8,16,25