Yolanda Luna
Did You Know?
- There is a huge amount of variation among the size of Hook-billed Kites' beaks! This difference isn't based on a bird's gender, though. Some individuals have beaks up to twice as large as other Hook-billed Kites, which likely has to do with a variation in the size of their main prey - tree snails - throughout their range.
- Though scientists long thought that these raptors were not migratory, researchers are finding evidence to the contrary! In Belize, local researchers counted about 5,000 individuals moving south in the fall of 2001.
- There is a subspecies of Hook-billed Kite found on the island of Grenada. There is also a Hook-billed Kite found only on the island of Cuba, but researchers believe this to be its own species.
How The Peregrine Fund is Helping
From 1988 to 1996, The Peregrine Fund was dedicated to studying Neotropical birds of prey in the Peten region of Guatemala in an ambitious undertaking called the Maya Project. All the information gathered on diet, nesting, threats and behavior helped contribute to the scientific world's knowledge of many of these species.This is important because the more we know about a species, the better we are able to help conserve it. The Peregrine Fund published the results of the Maya Project in a book called "Neotropical Birds of Prey, Biology and Ecology of a Forest Raptor Community."
Additionally, our efforts in scientific research, habitat conservation, education, and community development help conserve raptors on a global scale. We also supply literature to researchers from our avian research library, which helps scientists around the world gather and share important information on raptor conservation. We also support the Neotropical Raptor Network - a group that helps conserve birds of prey by improving communication and collaboration among raptor enthusiasts throughout the region!
Peregrine Fund staff and collaborators continue to conduct surveys of Grenada Hook-billed Kites to better understand the status and distribution of this population.
Where They Live
The Hook-billed Kite is found throughout a large part of the Americas, and is considered a Neotropical species. It makes its home throughout South America into northern Argentina. Its range continues north through Central America and Mexico, and even parts of Texas in the United States.
This truly unique looking raptor can be seen perching, hunting, soaring or nesting in lowland forest habitats, wooded freshwater swamps, mangrove swamps, gallery forest, palm forest, montane evergreen forest, deciduous forests, shaded coffee plantations, second-growth, or semi-open areas near water. In northern Mexico and southern Texas it inhabits dry acacia thorn woodlands and tropical deciduous forest.
What They Do
The Hook-billed Kite is quite a unique raptor, particularly because it varies so much in the size of its beak and the colors and patterns of its plumage. Males tend to be a solid bluish-gray color on their heads and backs, while their breasts are grayish and adorned with pale streaking in horizontal bars. Females tend to have brown upperparts, though the sides of their heads are gray. Their breasts are a rusty color decorated with thin, white bars.
Of course, you probably know that one of the characteristics of most raptors is a hooked beak. So, why was this kite named for a characteristic that most birds of prey exhibit? This is probably because individuals with large beaks have them in the extreme. Their beaks are quite large and hooked!
This incredibly beautiful raptor spends quite a bit of its time perching on tree branches. Researchers and bird watchers have noticed that it appears to be quite tame, meaning people can get relatively close to it without causing it flush or fly away. During the mid-morning, this bird sometimes enjoys soaring over the forest or open habitats. Though it is usually found hanging out by itself, or in family groups where three or four individuals are hanging out next to each other, researchers have occasionally observed this species flocking in groups of 10-20 individuals or more!
Why They Need our Help
The Hook-billed Kite is categorized as Least Concern. This is, in part, because it has a wide range as is considered to be rather common throughout. However, there is so much we still need to learn about this species, that is sometimes hard to find and therefore, study. Even though they are considered to be of Least Concern, researchers are noticing a decline in their numbers. Natural disasters, such as hurricanes which can fell trees, destroy habitats, and cause nests to fall, man-caused habitat destruction, and even introduced snails that feed on the Hook-billed Kite's native snail prey are all threats to this species.The endemic subspecies in Grenada is considered to be Endangered.
What They Eat
Looking at the large beak of a Hook-billed Kite might lead one to believe that it feeds on large mammalian prey. In fact, this species' diet actually consists mostly of terrestrial and arboreal snails, though it will sometimes feed on frogs, salamanders, lizards, crabs, insects, caterpillars, and spiders. In fact, if you compare their beak shape to another snail-eating raptor, the Snail Kite, you might notice some similarities. However, there are some differences too. The Hook-billed Kite's beak isn't specialized for piercing snail shells, like that of the Snail Kite. They extract the snails by breaking into the whorls of the shell.
Though the this kite's most-used hunting strategy probably involves the bird snatching prey as they slowly move along tree trunks and branches. But, it also sometimes waits patiently on a perch before flying to the ground to capture land snails or other prey. A good way to know if there is a Hook-billed Kite nearby is to search for a midden of broken and discarded snail shells beneath one of these bird's favorite feeding perches.
Nests, Eggs, and Young
As a rule, Hook-billed Kites breed later than other kite species. This might be due to seasonal changes in the abundance and availability of prey. For example, usually their eggs hatch right at the start of rainy season. It probably isn't a coincidence that that is when snails are most abundant!
Female and male Hook-billed Kites work together to build their nests, which are shallow and cup-shaped and built from small twigs and sticks. They place their nest in the crotch of a tree near the trunk or further out on a horizontal branch. Unlike other birds of prey, Hook-billed Kites don't tend to line their nests with other materials, though sometimes fresh twigs are added. Some researchers have described their nests as "remarkably flimsy" and for good reason. If you were to stand beneath a Hook-billed Kite's nest and look up, chances are you would be able to see the eggs and young through the bottom of the nest!
When the time is right, the female will lay 1-3 eggs, but most often they will lay 2. Their eggs are dull white and heavily spotted with dark brown blotches. After the eggs hatch, they need to be kept warm and safe for the next 34 days or so, so that the growing embryos can develop into healthy young. The process of sitting on and warming the eggs is called incubation and both parents take turns carrying out this duty, though the female might do a bit more of this than the male.
After the young hatch, they will grow quickly. While the male is responsible for catching and bringing food to the nest, both parents help in this duty and in feeding the young. And at around 38 or 39 days, the nestlings will be ready to fly for the first time.
Hook-billed Kite and the World Center for Birds of Prey
The World Center for Birds of Prey offers fun ways to learn about all birds of prey. Interactive activities, tours, interesting videos, and a children's room with activities from coloring sheets to quizzes to costumes await you. The visitor center has many live raptors on display, and in the fall you can observe some of the raptors showing off their flying skills during our Fall Flight Shows. This is a great chance to see birds of prey up close and learn about the wonderful and interesting adaptations they have in order to survive in their respective habitats. There is also a touch table with feathers and other natural objects available for exploration. Our knowledgeable staff is on hand year-round to answer any questions you may have about the Hook-billed Kite or any other bird of prey.
References:
Bierregaard, R. O., J. del Hoyo, G. M. Kirwan, N. Collar, J. S. Marks, and C. J. Sharpe (2020). Hook-billed Kite (Chondrohierax uncinatus), version 1.0. In Birds of the World (S. M. Billerman, B. K. Keeney, P. G. Rodewald, and T. S. Schulenberg, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.hobkit.01
de Dantas, S.M., Portes, C.E.B., Pinheiro, E. and Kirwan, G.M., 2018. A review of flocking behavior by Hook-billed Kite, Chondrohierax uncinatus, in South America. Revista Brasileira de Ornitologia, 26(1), pp.9-11.
Global Raptor Information Network. 2021. Species account: Hook-billed Kite Chondrohierax uncinatus. Downloaded from http://www.globalraptors.org on 23 Aug. 2021
Paulson, D.R., 1983. Flocking in the Hook-billed Kite. The Auk.
Smith, T.B. and Temple, S.A., 1982. Feeding habits and bill polymorphism in hook-billed kites. The Auk, 99(2), pp.197-207.
