A Tinamus is a genus of flightless birds found in dense forests in South and Central America. There are four known living species of Tinamus, though some taxonomists consider there to be up to ten. Tinamus are part of the family Tinamidae, which includes 47 species across two genera. The name “Tinamus” comes from a Tupi term meaning “cry of the forest”.
Appearance and Characteristics
Tinamus are medium-sized, stocky birds that range in length from 25-48cm (10-19 inches). Their shape is similar to partridges, with rounded bodies, small heads, and rather short, thick necks. The wings are short, rounded and lack the specialized flight feathers needed for flight. The tail is short in most species. The legs are long, strong and unfeathered, with three front toes. Overall they have compact, dense, soft plumage for insulation and camouflage.
Plumage is cryptically colored in various patterns of grays, browns, rufous and black. The underparts are paler and barred or spotted. Soft diffuse barring helps camouflage tinamous when on the forest floor. They have no brilliant colors or elongated feathers as seen in related cracids and megapodes. The bill is slender, decurved and yellowish. Eyes are small and iris color varies between brown, red or yellow. Sexes are similar though the female may be slightly larger on average.
Tinamous have a highly developed Sternothorax, the bony structure where flight muscles attach in flying birds. While they cannot fly, this allows them to flap their wings to help propel themselves into flight for short bursts to escape predators. Their bones are especially dense to withstand the impact of rapid takeoff and landing. Tinamous have been clocked running up to 48 km/hr (30 mi/hr).
Habitat
All members of the genus Tinamus inhabit primary or secondary tropical and subtropical moist lowland forests. Most species are found at lower elevations up to 1,500m (4,900ft), though the Slaty Tinamou has been recorded up to 2,600m (8,500ft). Tinamous require dense understory vegetation and leaf litter to forage, roost and nest. Some may occupy forest edges or regenerating clearings, but all require some connection to primary forest. Outside the breeding season some species may wander into more open habitats like plantations adjacent to forest boundaries.
Behavior
Tinamous are shy, cryptic birds that spend most of their time on the forest floor, where their inconspicuous plumage blends into the leaf litter. They walk slowly and carefully through the underbrush, stopping frequently to pick up seeds or insects. When startled they explosively burst into flight in a loud whir of feathers and crash back down within 50m. Tinamous are mostly solitary outside of breeding season. They may gather in small groups at choice sources of grit and calcium like mineral licks.
Tinamous have a wide repertoire of guttural calls, whistles, and bill snapping sounds for communication. The Great Tinamou and other species are well known for their loud, far-carrying booming calls that give them the name “forest partridges”. Calls are most frequent at dawn and dusk, or before rainfall. Both sexes call, with the female’s lower pitched. Tinamous have a relatively small voice box, or syrinx, given the volume of their vocalizations. The thin tracheal walls allow them to resonate sound more efficiently.
Diet
Tinamous are omnivorous, feeding on fruit, seeds, tubers, small vertebrates, insects, worms, snails and other invertebrates. They forage by walking slowly through the forest, bobbing their head down to pick at food items. Their diet varies seasonally depending on food availability. Tinamous play an important role in dispersing seeds from fruit when feeding, regurgitating intact seeds.
Here is an overview of the main dietary items for Tinamus:
Food Source | Examples |
---|---|
Fruit | Palms, laurels, figs, nutmeg |
Seeds | Kapok, palms, legumes |
Tubers | Wild yams, sweet potatoes |
Invertebrates | Ants, termites, beetles, earthworms, snails |
Vertebrates | Frogs, lizards, snakes, rodents |
Reproduction and Life Cycle
The breeding season for Tinamus is typically September to December but can vary by range. During this time they are more vocal and territorial. Tinamous are polygamous, with males mating with multiple females. Courtship consists of the male bobbing his head while emitting booming and roaring vocalizations to attract females. Once paired, the male will continue these displays to guard his mate from other males.
The nest consists of a scrape on the ground lined with leaves, usually hidden under dense vegetation. The female lays 3-5 glossy white or pale buff eggs over several days. She incubates them alone for 16-21 days before they hatch. The precocial young leave the nest with their mother shortly after hatching. She protects and broods them on the ground for their first few weeks until they can feed themselves. Young reach adult size at 2-3 months. Lifespan in the wild is typically 8-10 years.
Key Facts on Tinamus Reproduction
- Polygamous mating system
- Male booming courtship displays
- Simple ground nest scrape
- Female incubates 3-5 eggs for 16-21 days
- Precocial young can feed independently soon after hatching
- Young reach adult size by 2-3 months
- Lifespan is 8-10 years in the wild
Species
There are four extant members of the Tinamus genus:
Great Tinamou
The largest Tinamus species, reaching 48cm (19in) and weighing up to 1.2kg (2.6lbs). Found in tropical forests from Mexico to Argentina. Recognized by its robust bill and reddish legs. Scalloping on breast and neck is heavy. Call is a far-carrying, booming hoot.
White-throated Tinamou
A mid-sized Tinamus at 33cm (13in) and 450g (1lb). Occurs in lowland forest interiors from Honduras to Bolivia and southcentral Brazil. Has distinctive white throat and fine barring on breast. Legs are pinkish. Call is a loud, ascending whistle.
Grey Tinamou
One of the smaller members at 28cm (11in) and 280g (10oz). Inhabits tropical forests from Veracruz, Mexico to northwest Peru. Legs are red. Plumage is overall grey with thin white barring on breast. Male’s call is a resonant hooting.
Slaty-breasted Tinamou
Similar in size to the Grey at 27cm (10.5in). Found in lowland forests from eastern Panama to northwest Peru. Has distinctive slaty black plumage on upper breast in male. Legs are pinkish. Call is a loud, hollow gobble.
Evolutionary History
The evolutionary origins of Tinamus date back to the early Miocene, 5-23 million years ago. The traditional placement of tinamous was with the ratites (ostriches, emus, etc) given their inability to fly. However genetic evidence shows tinamous are an early branch of the basal galliform (landfowl) radiation. Their resemblance to ratites is now considered an example of convergent evolution.
Tinamous were once far more widespread, with fossil genera like the giant Rhynchotus and mid-sized Nothura having ranges extending into North America and Europe in the Miocene. As habitats shifted they became restricted to the neo-tropics where they now reside. Today their closed-canopy forest habitats are increasingly threatened by fragmentation and clearing.
Relationship to Humans
Tinamous have long been important to indigenous cultures in South and Central America. They are depicted in artwork and folklore, and their meat and eggs used for subsistence. Tinamous are still commonly hunted where permitted. Their booming calls give them an importance in Amerindian stories. In parts of their range they are known as the “bird that stops you in your tracks” for their startling call.
Tinamous are also popular in the pet trade, though most captive birds are now captive bred as taking from the wild is restricted. Their extreme shyness means they do not adapt well to captivity. Tinamous are not globally threatened, but many species have declining populations due to habitat loss. They are also susceptible to overhunting. Four species are currently classified as Near Threatened and conservation actions are needed throughout their range.
Conclusion
In summary, Tinamus are a genus of modestly-sized, secretive forest birds native to Central and South America. They are an ancient lineage related to other landfowl like quail, adapted for life on the forest floor. Tinamus have dense, cryptic plumage and can burst into brief flight when startled. They play an important role dispersing seeds in tropical forest ecosystems. While not globally threatened, many species are in decline from habitat loss and hunting. Further conservation efforts are needed to preserve these birds and the forests they depend on.