AnimaliaHighest rank in taxonomy. Groups all life into domains: Animalia, Plantae, Fungi, etc.IUCN LCInternational Union for Conservation of Nature — the world authority on species extinction risk, using standardized criteria. — Least Concern — widespread and abundant; not at immediate risk of extinction.In ProgressCurrent stage of this record in the editorial review workflow. Recent Sighting
Chondrohierax uncinatus
Hook-billed Kite
(Temminck, 1822)
Detailed Texts Multi-lang
A medium-sized, highly variable raptor distinguished by its extraordinarily large, heavily hooked bill and distinctive paddle-shaped wings. The species is famous for extreme color polymorphism and sexual dimorphism: adult males are typically uniform slate-grey with fine white underpart barring; females are rich brown above with an orange-buff collar and heavy rufous barring below. An entirely black melanistic morph also occurs in both sexes. A bright, naked patch of greenish-yellow skin sits between the dark eye and the bill, and the legs are rich yellow.
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Julia Trouin
TaxonomyBiological classification ranks placing this species within the tree of life, from Kingdom down to Genus.
PhylumRank below Kingdom. Groups organisms sharing a fundamental body plan (e.g., Chordata = vertebrates and some invertebrates).Chordata
ClassRank below Phylum. Subdivides by structural traits (e.g., Mammalia, Aves, Reptilia, Insecta).Aves
OrderRank below Class. Groups related families sharing common ancestry (e.g., Carnivora, Primates).Accipitriformes
FamilyRank below Order. Groups closely related genera (e.g., Felidae = cats, Canidae = dogs).Accipitridae
GenusRank just above Species. The first word in the two-part binomial scientific name.Chondrohierax
Taxonomic AuthorityThe scientist who first formally described and published this species, followed by the year of publication.(Temminck, 1822)
Record Completeness
96%Coming soon
Ecology & StatusHow this species lives: habitat preferences, diet, behavior, population status, and role in its ecosystem.
OriginWhether the species is native (evolved here), endemic (found only here), or introduced by human activity.
Native
Population TrendDirection of change in population size over time: increasing, stable, decreasing, or unknown.
Decreasing
Breeding SeasonTime of year when this species typically reproduces or flowers.
Year Round
Trophic RolePosition in the food chain: producer, herbivore, carnivore, omnivore, decomposer, or parasite.
Carnivore
Recent SightingsWhether this species has been observed in the wild in Costa Rica within recent years.
Yes
Habitat SummaryOverview of the specific ecosystems and environments where this species is found in Costa Rica. Multi-lang
Inhabits a broad variety of wooded tropical environments, showing a strong preference for humid lowland forests, swamp woodlands, riverine galleries, mangroves, and semi-arid deciduous forests. It relies heavily on sub-canopy and mid-story vegetation where its specialized land snail prey is abundant.BehaviourDaily activity patterns, movement, territory use, foraging style, and seasonal behavioral changes. Multi-lang
A lethargic, slow-moving raptor that spends extended periods perched quietly within dense foliage, peering intently at branches and leaves to detect snails. Unlike typical kites, it rarely soars openly in the wind. When hunting, it uses its foot to hold a snail shell firmly against a branch, then meticulously uses its specialized bill to hook out the soft animal body.Social ActivitySocial structure: whether the species is solitary, paired, or colonial; hierarchy and communication. Multi-lang
Primarily solitary or found in pairs during the nesting season. Due to the clumped nature of their specialized food source, multiple individuals may occasionally forage peacefully in the same fruiting or snail-rich grove without showing strong territorial aggression, which is unusual for raptors.Feeding GuildWhat the species eats, how it forages or hunts, and its role as a consumer in the food web. Multi-lang
Carnivore (molluscivore; highly specialized predator focusing almost exclusively on arboreal and terrestrial land snails).Trophic Chain DetailsSpecific interactions in local food webs: prey species, predators, competitors, and scavengers. Multi-lang
Occupies a highly specialized consumer niche, serving as the premier avian predator of arboreal land snails (especially those of the genus Homalonyx and Orthalicus). It occasionally diversifies with frogs, salamanders, and caterpillars. Adults are rarely preyed upon, but nest contents are vulnerable to larger forest raptors and monkeys.Reproductive BehaviourMating strategies, courtship displays, nesting or spawning behavior, and parental care. Multi-lang
Monogamous pairs construct a surprisingly flimsy, shallow, and loosely woven nest of brittle sticks and vines, lined with green leaves, usually hidden high in dense foliage. The female lays 1 to 2 dull white eggs heavily washed or blotched with reddish-brown. Both parents share incubation duties for about 28 days and cooperate equally in bringing extracted snail meat to the hatchlings.Physical Measures
Length (cm)
38.0 - 51.0 cm
Weight (Grams)
215 g - 360 g
Offspring per cycleTypical number of young (live births, eggs, or seeds) produced by one adult in a single reproductive event or breeding season.1 - 2
Sexual DimorphismObservable physical differences between males and females of the same species (e.g., size, coloration, features).Yes
Lifespan
Sexual MaturityAge at which the individual becomes capable of reproducing for the first time.
2 - 3 Years
Gestation / IncubationDuration from fertilization to birth (mammals) or to hatching (egg-laying species).
27 - 30
Lifespan EstimatedExpected duration of life from birth to natural death under wild conditions.
Males8 - 13 Years
Females8 - 13 Years
Sexual DimorphismPhysical differences in size, coloration, or morphology between males and females of this species.
Males Multi-lang
Adult males exhibit a remarkably clean, uniform blue-grey to dark slate-grey plumage over their head, back, and upper wings. Their underparts are pale grey to white, finely and densely barred with dark charcoal horizontal lines. Iris ranges from white to pale greenish-white.
Females Multi-lang
Adult females differ completely from males, displaying dark brown upperparts, a prominent cinnamon-rufous neck collar, and a creamy underbelly broadly and coarsely barred with bold reddish-brown or chestnut bands. Iris is typically a contrasting golden-yellow.
Evolutionary AdaptationsInherited traits and behaviors that improve the species' survival and reproduction in its specific environment. Multi-lang
The heavily curved, specialized bill is an evolutionary marvel designed specifically to wedge into the apertures of large tree-snails (like Bulimulidae), slicing the columellar muscle to extract the meat without breaking the shell.
Exhibits unique genetic variation in bill size within the same geographic population, with large-billed and small-billed individuals coexisting to exploit different size classes of local snail populations.
Main ThreatsDocumented pressures reducing the population: habitat loss, hunting, disease, climate change, and invasive species. Multi-lang
Extremely vulnerable to the widespread use of agricultural pesticides and herbicides that decimate terrestrial and arboreal snail populations. Severe habitat fragmentation and clearing of subtropical woodlands also restrict its specialized foraging areas.
Interesting FactsSurprising or notable facts that highlight what makes this species unique or ecologically important. Multi-lang
Because its diet is so hyper-specialized on snails, the Hook-billed Kite's local abundance and movements are completely nomadic and tied directly to the seasonal population booms and weather-dependent activity of land mollusks.
The variation in plumage and bill size is so massive that early 19th-century ornithologists erroneously described this single species under more than a dozen different scientific names before genetic sequencing grouped them.