Natural history and taxonomy
The birds of family Ramphastidae are found in South and Central America, from central Mexico to southern Brazil, and include the large toucans, the small aracaris, and smaller toucanets.1 Known for their large and colorful bills, this group consists of at least five genera and over 40 species.23
Order: Piciformes (woodpeckers, honeyguides, barbets, jacamars, puffbirds)
Ramphastos: large, black toucans
Andigena: large, mountain-ranging toucans
Aulacorhynchus: green mountain toucanets
Selenidera: lowland, forest-ranging toucanets
In captivity, toucans are charismatic birds that are popular in zoos and aviaries. They are occasionally kept by aviculturists or as household pets.25,26 Toco toucans (Ramphastos toco) and sulfur-breasted or keel-billed toucans (R. sulfuratus) are commonly seen in clinical practice.25 Swainson’s toucan, also known as the chestnut-mandibled toucan (Ramphastos ambiguus swainsonii) is also commonly imported. Many araçaris and toucanet species are also seen in aviculture and as pets (Kuchinski, email message to editor, Nov 3, 2021).
The International Union for Conservation of Nature (IUCN) Red List describes most free-ranging ramphastid populations as of “least concern”.13 Although numbers are decreasing for most species, few species are threatened with extinction.13
|Grey-breasted mountain toucan (Andigena hypoglauca)||Near threatened|
|Plate-billed mountain toucan|
|Saffron toucanet (Pteroglossus bailloni)||Near threatened|
|Yellow-throated toucan |
|Channel-billed toucan |
|Red-billed toucan |
|Yellow-ridged toucan |
|Ariel toucan (Ramphastos ariel)||Endangered|
|Eastern red-necked araçari (Pteroglossus bitorquatus)||Endangered|
Normal physiologic values
|Ramphastid species||Body weight (grams)1|
|Green aracari||Pteroglossus viridis||120-160|
|Ivory-billed aracari||P. azara||130-160|
|Curl-crested aracari||P. beauharnaisii||180-280|
|Crimson-rumped toucanet||Aulacorhynchus haematopygus||200-230|
|Black necked aracari||P. aracari||230-250|
|Keel-billed toucan||Ramphastos sulfuratus||280-400|
|Plate-billed mountain toucan||Andigena laminirostris||300-350|
|White-throated toucan||R. tucanus||450-600|
|Toco toucan||R. toco||550-800|
|Musculoskeletal||The feet of these birds are zygodactyl, with digits 2 and 3 facing forward and digits 1 and 4 directed back.16
The tail vertebrae are modified so that birds are capable of rotating their tails forwards to touch their heads. This is a common sleeping position.23
|Gastrointestinal||The large bill consists of spongy bone protected by a thin wall of keratin, the rhamphotheca.10,21 The bill is serrated, highly vascular and extremely sensitive. The internal beak is supported by bony struts, but the beak is also very lightweight and can be easily injured (see common medical conditions below).23 Many functions have been proposed for these magnificent bills, including foraging, courtship, aggression, and thermoregulation.23,24
The thin, delicate tongue features laminated sides and a brush-like tip. Some ramphastids will rattle the tongue against their bill to produce a characteristic rattling sound.
Ramphastids do not have a crop or cecum.3,23 Some toucans possess an elongated gall bladder.15
Ramphastids produce voluminous, wet fecal droppings. In fact, the droppings frequently look like undigested food, particularly fruit (Cubas and Kuchinski, email messages to editor, Nov 3, 2021).
A survey of normal cloacal flora in toucans and aracari found Gram-negative bacteria (E. coli, Klebsiella spp., Enterobacter spp.) as well as Gram-positive cocci (Staphylococcus spp., Streptococcus spp.) (Cornelissen 1991)
|Respiratory ||Ramphastids have a ventral deviation of the trachea at the thoracic inlet which can be appreciated radiographically (select lateral radiograph image left to enlarge).6,23
|Integumentary||Adult birds lack down feathers 16, although powder down has been described in toucans.20
The apterylae, or the space between feather tracts, can be quite large making venipuncture relatively easy.
Plumage color may become faded in captive birds due to inadequate dietary carotenoids (Cubas, email message to editor, Oct 18, 2021).
|Reproductive||Most ramphastids, including the keel-billed toucan, have melanistic or colored gonads.25
The vast majority of captive ramphastids are kept as aviary birds in breeding situations.25 Toucans are cavity-nesting birds. Some species take over the nests of woodpeckers, while others, especially the larger species, use their bills to make a hole and hollow out decaying limbs of trees. Both sexes share incubation and rearing duties.23
The general convention in captive toucans is to provide a hollowed-out section of palm log to facilitate breeding. Some breeders have been successful with conventional plywood nest boxes, especially when they have been modified to include an external bark tile covering with cork over the entrance hole to allow the birds to “hollow it out”. Captive birds may be parent reared but are also often hand reared.23
See Behavior for additional information.
|Pediatrics||Eggs per clutch in toucans, toucanets: 2 to 4 23
Incubation period in toucans, toucanets: 15-16 days23
When compared to toucans, toucanet and araçari offspring have higher survival rates, averaging 80% (Dislich 2014). Causes of chick mortality include infanticide by parents, stomach impaction, and bacterial disease (Dislich 2014).
Neonates usually have a hypotarsal pad (or heel pad) on their hocks, that they use to rest on the ground, rather than standing on two feet while in the nest. These pads atrophy as birds mature.6,23
Chicks leave the nest at 6-7 weeks of age and begin eating on their own at 10-12 weeks of age (Dislich 2014).23
See Diet for information on hand feeding.
|Sexual dimorphism||Most ramphastids are phenotypically monomorphic 23, although male birds tend to have a larger beak than females.4,25 Measurement of the upper bill from the origination with the facial skin to the tip may also be helpful in determining sex. In mature toco toucans, it has been suggested that birds with upper bill length <15.5 cm are usually females but if the length exceeds 16 cm the bird is usually a male.25
DNA sexing and endoscopy are the most reliable methods of sex determination in monomorphic species.
Sexually dimorphic birds include lowland toucanets of genus Selenidera and two of the araçaris, P. viridis and P. inscriptus (lettered araçaris).23,25
Ramphastids are primarily frugivores, although they are opportunists and will also eat insects and small birds or reptiles.23 Free-ranging ramphastids play a crucial ecological role in the dispersal of the seeds of fruit trees. Ramphastids consume a variety of fruits and seeds, such as fruits of Ficus, guava, and palm trees (Euterpe spp.) as well as chili pepper 10b.
In captivity, ramphastids should be offered diced, mixed fruit. Toucans especially enjoy colorful fruits, such as papaya and berries.14 They will also readily consume bananas and a variety of melons.14 Due to the high risk of iron storage disease in these birds, the diet should be iron restricted. Avoid citrus fruits, tomatoes, and pineapple, as these contain high levels of citric acid and ascorbic acid, which increase iron absorption.14,23
Ramphastids also require a source of high protein not available in fruit.14 Offer a nutritionally complete, formulated toucan pellet with low iron (< 150 ppm). The total iron content of the diet should ideally be less than 40 ppm (20-60 ppm). There is some debate about the best dietary iron levels for optimal reproductive performance (Kuchinski, email message to editor, Nov 3, 2021), however dietary iron is generally limited except when raising chicks, which need animal protein for growth.23
When compared to psittacine birds, hand feeding time is prolonged due to the absence of a crop.22b, 23 For instance, it can take up to 30 minutes to feed a 2-3 week old bird.22b Commercial hand feeding formulas developed for psittacine birds can be used in toucans; this diet can be supplemented with fruit.22b,23
Ramphastids are very active birds that should be housed in large, lightly planted aviaries that allow them to move around enclosures by hopping from branch to branch.9,14,23 Ramphastids also require ample space.23 Large toucans should be housed in aviaries 4 m wide, 7-8 m deep, and 2-3 m high.9,14 It is also important that some visual security be provided. 9,14
Although most ramphastids are relatively cold-tolerant, these birds can be sensitive to frostbite in temperate climates. Some species, such as the toco toucan, have been reported to be particularly susceptible to frostbite in winter.25 These birds should be brought inside during the colder months in temperate climates.23
Although some of the larger toucans, and to a lesser extent the larger araçaris like the chestnut-eared (P. castanotis), can be noisy, these birds are far quieter than most psittacine birds.
Ramphastids enjoy bathing and should be provided large water receptacles.14
Sanitation and vermin control are also important (see Infectious Diseases and yersiniosis below). Elevate food dishes off of the ground, ideally on freestanding structures.23
Toucans are social birds that often spend their time in flocks of dozens. Pairs may split off for breeding but return to flocks with their offspring.
Toucans are also territorial birds.23 Mate aggression, fights between males, and interspecies aggression are common.10 Reproductively active birds are particularly territorial. During the breeding season, males caged next to each other without the presence of a visual barrier may injure their beaks by engaging in beak jousting.10
Many captive parent birds will reject their young in response to stressors, such as inspection of the nest log. Therefore some breeders place a camera in the nest box to minimize both the need for inspections and parental stress (Kuchinski, email message to editor, Nov 3, 2021).
Ramphastids can be aggressive and can inflict painful injuries to handlers. Use a towel to remove birds from the cage. Manual restraint can involve holding the bill, taking care not to obstruct the nares, which are located at the base of the upper bill.10 The beak is easily damaged if too much side-to-side pressure is applied.12
Netting is also theoretically possible, but realistically quite challenging. Ramphastids can be remarkably quick putting birds at significant risk for injury during capture.
Inhalant anesthetic induction of a toco toucan using a small human pediatric mask placed over the nares at the base of the bill has been described 12, alternatively a mask can be constructed from a cylindrical plastic bottle, like a soda bottle, to accommodate the long beak.10,12,23 To reduce mechanical dead space the mask should be the exact size of the beak.10 The beak of the smaller araçaris and toucanets fit into a large dog mask.
Endotracheal intubation is a relatively simple procedure in ramphastids. The small, filamentous tongue makes the glottis easy to visualize.10
Important medical conditions
Iron storage disease
Iron storage disease is the most famous clinical condition of ramphastids.6,7,22,23 It is important to make the distinction between hemosiderosis and hemochromatosis, the former being a potentially physiological presence of iron in the tissues which does not result in inflammation, the latter being a pathological condition which results in cellular derangements.
More research is needed, however it is thought that high levels of dietary iron is an important predisposing factor. Free-ranging ramphastids typically eat diets that are low in iron and have potentially evolved to retain iron very effectively.2 Diets should be limited to 20-60 ppm of iron, although they may be slightly higher during the breeding season when chicks are being reared. A lack of tannins in the diet has also been theorized as a possible risk factor for excess absorption of iron in the intestines. It is thought that wild birds consume water from cavities in trees that have been leached with tannins from plants. Ascorbic acid increases the bioavailability of iron and diets containing citrus fruits may also predispose to iron storage disease. Stress has also been suggested as a contributing factor.6,7,22,23
Clinical signs include lethargy, anorexia, abdominal distension, ascites, dyspnea, neurological signs, and sudden death. Liver biopsy is the diagnostic test of choice. Liver enzymes and bile acids may be elevated on biochemistry analysis. The use of MRI to measure the iron content of the liver has shown promise in other species and may have a place in avian medicine for diagnosis and monitoring of this condition. Treatment is with weekly phlebotomy of 1% of body weight. The use of iron chelators such as deferoxamine (100 mg/kg q24h SQ) or deferiprone (50 mg/kg q12h PO) for 30 days has also shown positive results.6,7,22,23 Intestinal iron absorption can also be reduced by adding tannin-rich items, such as black tea, and phytates 10b. Supportive care and symptomatic treatment is also indicated.6,7,22,23
Ramphastids are known to be especially sensitive to yersiniosis (Yersinia pseudotuberculosis). This disease is usually spread by rodents entering enclosures and a strict rodent exclusion protocol is particularly important where these birds are kept.18
Bacterial septicemia has often been reported in ramphastids, caused by a variety of species including Coxiella spp., Bacteroides spp., Mycobacteria spp., Escherichia coli and Salmonella spp.23
Capillariosis is common and a significant cause of mortality in captive toucans.10,23 Clinical findings may include lethargy, dehydration, and emaciation.23 Many birds will ingest their droppings, which can be an issue when trying to control parasite loads within aviaries (Kuchinski, email message to editor, Nov 3, 2021).
Damage to the beak
The beak is very lightweight and can be easily injured.25 Beak injuries occur most frequently in young birds that are learning to fly or that have been recently introduced into a new flight.25 The beak also tends to be softer and more susceptible to injury in juvenile birds.23
Urgent care of beak injury involves control of hemorrhage. Apply pressure for a few minutes with a gauze pad moistened with an antiseptic solution. Remove debris and gently clean, then thoroughly dry the wound.10 Take care not to introduce liquid or debris into the spongy bone, which can carry contaminants to deeper parts of the beak or sinuses.10 Apply water-soluble antibiotic ointments to the wound and tape gauze dressings over the defect.10 Replace dressings every 24 hours until hemorrhage and infection are controlled.10 Parenteral antibiotics are often indicated. Biocompatible cellulose membrane or other dressings can be used to treat open wounds and fractures in the beak.
Beak repair techniques using dental adhesive systems, orthognathic correction with molds, surgeries and beak prosthesis can be employed in toucans 10c. Both natural and artificial beak prostheses have been used to restore function in birds with traumatic beak deficits. Natural beak prostheses may be alloplastic (from the same species) or heteroplastic (from a different species).9,11
Diabetes mellitus has been reported in keel-billed and toco toucans. As in other species, weight loss, polyuria, polydipsia, and polyphagia may all be seen. Hyperglycemia and glycosuria are usually appreciable with diagnostic investigation. Initial treatment with PZI or NPH insulin has been successful, followed by long-term insulin treatment on a daily or every other day basis. Dietary modification may also be a consideration. 17,23
Diabetes may be associated with iron storage disease, since iron deposits may be seen in the pancreas as well as the liver 9b (Cubas, email message to editor, Oct 18, 2021).
Metabolic bone disease
Nutritional secondary hyperparathyroidism is reported commonly in young birds fed a calcium-deficient diet.23 Chicks may refuse to eat formulated diet in preference to tastier fruit.23,25 The beak may become soft and rubbery, or the pelvic limbs may be bent or bowed. In some cases, trauma from flying into aviary walls with underlying metabolic bone disease issue can result in fracture of the bill tip. Recommended dietary modifications include increasing calcium levels along with supplementation of calcium or vitamin D3. Provision of an UVB bird lamp is also likely to be beneficial for birds that are housed indoors.
Other reported conditions
- Foreign body ingestion may be seen in ramphastids due to the curious nature of these birds.25 Foreign bodies, such as sticks or large insects, can also be fed to chicks by parent birds (Kuchinski, email message to editor, Nov 3, 2021).
- Herpesvirus infection causing necrotizing hepatitis and sudden death was reported in a toucan, species unknown. The etiologic agent was thought to be distinct from psittacine herpesvirus (Pacheco’s disease).5
- An outbreak of ulcerative enteritis caused by Clostridium colinum caused sudden death in a group of young toucans 24b.
- Chlamydia psittaci has been demonstrated in toucans, however these birds do not seem as predisposed to developing clinical disease as other species, such as psittacine birds.19
- Candidiasis has also been reported in ramphastids, especially in young, hand fed birds.23 Other fungal diseases, such as aspergillosis, have also been described.23
References and further reading
1. Alvarenga H. Toucans of the Americas. Brazil: M Pontual Edicoes E Arte; 2004.
2. Amber V. Drews, Sharon P. Redrobe, Janet C. 2004. Patterson-Kane. Successful reduction of hepatocellular hemosiderin content by dietary modification in Toco toucans (Ramphastos toco) with iron-storage disease. J Avian Med Surg 18(2):101-105.
3. Andrade MB, Santos AL, Hirano LQ, de Moraes, FM. 2016. Anatomy of the digestive tube of toco toucan. PUBVET, 6, Art-1345.
4. Castro MS, Recco-Pimentel SM, Rocha GT. 2003. Sexual dimorphism in Ramphastos toco and Ramphastos dicolorus (Piciformes, Aves). Rev Biol Trop. 51(1):241-5. PMID: 15162699.
5. Charlton BR, Barr BC, Castro AE, Davis PL, Reynolds BJ. 1990. Herpes viral hepatitis in a toucan. Avian Dis. 34(3):787-790.
6. Cornelissen H, Ritchie BW. Ramphastidae. In: Ritchie BW, Harrison GJ, Harrison LR (eds). Avian Medicine: Principles and Application. Lake Worth, Florida. Winger’s Publishing Inc; 1994:1276-1283.
7. Cornelissen H, Ducatelle R Roles S. 1992. Successful treatment of a channel-billed toucan (Ramphastos vitellinus) with iron storage disease by chelation therapy: Sequential monitoring of the iron content of the liver during the treatment period by quantitative chemical and image analysis. J Avian Med Surg. 9(2):131–137.
7b. Cornelissen JM, van den Brink ME, Bakker MH, Koopman JP. 1991. Cloacal microflora of healthy hornbills, toucans and aracaris. Tijdschr Diergeneeskd. 116 Suppl 1:84S-85S. PMID: 2048092.
8. Crosta L. 2002. Alloplastic and heteroplastic bill prostheses in 2 Ramphastidae birds. J Avian Med Surg 16(3):218-222.
9. Crosta L, Timossi L. The management of a multi-species bird collection in a zoological park. In: Tully JR TN, Dorrestein GM, Jones AK (eds). Handbook of Avian Medicine, 2nd ed. Philadelphia: Saunders Elsevier; 2009:404-436.
10. Cubas ZS. Medicine: Family Ramphastidae (toucans). In: Fowler ME, Cubas ZS (eds). Biology, Medicine, and Surgery of South American Wild Animals. Ames, IA: Iowa State University Press; 2001:188-199.
10b. Dislich M. Piciformes (Tucanos, araçaris e pica-paus) Piciformes (toucans, aracaris and woodpeckers). In: Cubas ZS, Silva JCR, Catão-Dias JL (eds). Tratado de Animais Selvagens Medicina Veterinária (Wild Animals Veterinary Medicine), 2nd ed. São Paulo: Editora Roca Ltda., Grupo Editorial Nacional; 2014:598-625.
10c. Fecchio RS, Gioso MA. Correções ortognáticas e prótese em bico de aves (orthognathic corrections and bird beak prostheses). In: Cubas ZS, Silva JCR, Catão-Dias JL (eds). Tratado de Animais Selvagens Medicina Veterinária (Wild Animals Veterinary Medicine), 2nd ed. São Paulo: Editora Roca Ltda., Grupo Editorial Nacional; 2014:2056-2067.
11. Fecchio RS, Seki Y, Bodde SG, et al. 2010. Mechanical behavior of prosthesis in Toucan beak (Ramphastos toco). Materials Science and Engineering: C. 30(3):460-464.
12. Heard D. Birds: Miscellaneous. In: West G, Heard D, Caulkett N (eds). Zoo Animal and Wildlife Immobilization and Anesthesia, 2nd ed. Ames IA: Wiley Blackwell; 2014.
13. IUCN 2021. The IUCN Red List of Threatened Species. Version 2021-2. Available at https://www.iucnredlist.org/. Accessed October 2, 2021.
14. Jennings J. Captive management: Family ramphastidae. In: Fowler ME, Cubas ZS (eds). Biology, Medicine, and Surgery of South American Wild Animals. Ames, IA: Iowa State University Press; 2001:186-188.
15. King AS, McLelland J. Digestive system. In: Birds: Their Structure & Function. Philadelphia PA: Baillière Tindall; 1984: 107.
16. Mikich SB. Biology, Order Piciformes (Toucans, Woodpeckers). In: Fowler ME, Cubas ZS (eds). Biology, Medicine, and Surgery of South American Wild Animals. Ames, IA: Iowa State University Press; 2001:180.
17. Murphy J. 1992. Diabetes in Toucans. In: Annual Proceedings of the AAV. New Orleans. Association of Avian Veterinarians. 253-262.
18. Nakamura S, Hayashidani H, Sotohira Y, Une Y. 2016. Yersiniosis caused by Yersinia pseudotuberculosis in captive toucans (Ramphastidae) and a Japanese squirrel (Sciurus lis) in zoological gardens in Japan. J Vet Med Sci. 78(2):297-299. doi: 10.1292/jvms.15-0298. Epub 2015 Sep 5. PMID: 26346565; PMCID: PMC4785121.
19. Raso TDF, Ferreira VL, Teixeira RHF, Pinto AA. 2012. Survey on Chlamydophila psittaci in captive ramphastids in São Paulo State, Brazil. Ciência Rural 42(7):1249-1252.
20. Reavill DR, Dorrestein G. Psittacines, Coliiformes, Musophagiformes, Cucucliformes. In: Pathology of Wildlife and Zoo Animals, 2018.
21. Seki Y, Bodde SG, Meyers MA. 2010. Toucan and hornbill beaks: a comparative study. Acta Biomater. 2010 Feb;6(2):331-43. doi: 10.1016/j.actbio.2009.08.026. Epub 2009 Aug 21. Erratum in: Acta Biomater. 6(6):2363. PMID: 19699818.
22. Sheppard C, Dierenfeld E. 2002. Iron storage disease in birds; speculation on etiology and implications for captive husbandry. J Avian Med Surg. 16(3):192–197.
23. Sykes IV JM. Piciformes (Honeyguides, Barbets, Woodpeckers, Toucans). In: Miller RE, Fowler ME (eds). Fowler’s Zoo and Wild Animal Medicine. Volume 8. St Louis, Missouri, Elsevier; 2015:230-236.
24. Tattersall GJ, Andrade DV, Abe AS. 2009. Heat exchange from the toucan bill reveals a controllable vascular thermal radiator. Science. 325(5939):468-70. doi: 10.1126/science.1175553. PMID: 19628866.
24b. Walker RL, Anderson MA, Loretz KJ. Ulcerative enteritis in toucans. Proc Annu 39th Annual Meeting of American Association of Veterinary Laboratory Diagnosticians. Little Rock, AK 1996: 19.
25. Worell AB. Toucans and mynahs. In: Altman RB, Clubb SL, Dorrestein GM, Quesenberry K (eds). Avian Medicine and Surgery. Philadelphia: WB Saunders; 1997: 910-915.
26. Worell AB. Ramphastids. In: Tully JR TN, Dorrestein GM, Jones AK (eds). Handbook of Avian Medicine, 2nd ed. Philadelphia: Saunders Elsevier; 2009:335-349.
da Silva JP, Rahal SC, Castiglioni MCR, et al. 2021. Ultrasonography of the gastrointestinal tract of toco toucans (Ramphastos toco). Anat Histol Embryol. doi: 10.1111/ahe.12737. Epub ahead of print. PMID: 34533230.
da Silva JP, Rahal SC, Castiglioni MCR, et al. 2020. Radiography and computed tomography of the heart and lower respiratory tract in toco toucans (Ramphastos toco). Anat Histol Embryol. 49(4):541-549. doi: 10.1111/ahe.12559. Epub 2020 Apr 7. PMID: 32266741.
Dislich M, Oliva LR, Neumann U. 2021. Clinical observations of bee envenmation in toucans. J Zoo Wildl Med. 52(2):787-794. doi: 10.1638/2020-0037. PMID: 34130427.
Ragusa-Netto J. 2006. Abundance and frugivory of the Toco toucan (Ramphastos toco) in a gallery forest in Brazil’s southern Pantanal. Braz J Biol. 66(1A):133-42. doi: 10.1590/s1519-69842006000100017. Epub 2006 May 2. PMID: 16680316.
Sun CH, Liu HY, Zhang Y, Lu CH. 2018. Comparative analysis of the gut microbiota of hornbill and toucan in captivity. Microbiologyopen. 27;8(7):e786. doi: 10.1002/mbo3.786. Epub ahead of print. PMID: 30592177; PMCID: PMC6612546.
Abou-Zahr T. Basic information sheet: Ramphastidae. Nov 4, 2021. LafeberVet web site. Available at https://lafeber.com/vet/basic-information-sheet-ramphastidae/