 |
 |
 |
By Alicia Ivory
Geographic Range
Broad-winged hawks are native to the Nearctic and Neotropical regions. They breed throughout the eastern United States and most of southern Canada. Their winter range includes southern Florida, the Pacific slope of southern Mexico, Central America and northern South America. (Goodrich, Crocoll, and Senner, 1996; Snyder and Snyder, 1991)
Habitat
(6560 ft)
Broad-winged hawks favor dense deciduous or mixed deciduous-coniferous forests for nesting. They prefer to have water and openings such as roads, trails, wetlands or meadows nearby. Broad-winged hawks use these openings in the canopy for foraging. They tend to avoid nesting near human dwellings.
Broad-winged hawks' winter habitat is deciduous and mixed forest habitats in Central and South America. They may live anywhere between sea level and several thousand meters elevation. ("The University of Minnesota Raptor Center and Information About Raptors", 2004; Goodrich, Crocoll, and Senner, 1996)
These animals are found in the following types of habitat:
temperate 
; tropical ; terrestrial .
Terrestrial Biomes:
forest ; rainforest ; scrub forest .
Physical Description
(9.33 to 19.71 oz; avg. 14.52 oz)
(13.39 to 17.32 in)
(31.89 to 39.37 in)
Broad-winged hawks are small, stocky hawks. They are about 34 to 44 cm long and weigh 265 to 560 g. Their wingspan ranges from 81 to 100 cm. Adults have a dark brown back and a pale underside with horizontal cinnamon or chestnut barring. The tail is dark gray to black with a conspicuous broad white stripe across the middle and two less conspicuous white stripes at the base and tip. In flight, broad-winged hawks have pointed wing tips. When perched, the wing tips of broad-winged hawks don't reach the end of the tail.
Rare dark (melanistic) morphs of broad-winged hawks are occasionally seen in the northern part of the geographic range. These birds are entirely dark brown, with a tail similar to typical adults.
Juvenile broad-winged hawks are similar in appearance to adults, but have longitudinal, rather than horizontal barring on their chest and belly. Juveniles also tend to have more white on their chest and belly than adults. Males and females of any age look similar, though females tend to be larger than males (about 22% heavier). ("The University of Minnesota Raptor Center and Information About Raptors", 2004; Goodrich, Crocoll, and Senner, 1996; Snyder and Snyder, 1991)
Some key physical features:
endothermic ; bilateral symmetry ; polymorphic .
Sexual dimorphism: female larger; female larger.
Reproduction
Broad-winged hawks breed once yearly. They raise one brood per breeding season.
Broad-winged hawks breed between April and August.
Broad-winged hawks are monogamous. Breeding pairs form soon after arrival on breeding grounds in the spring, around mid- to late-April. Courtship behaviors include flight displays and possibly courtship feeding, though this has not been well documented. Breeding pairs may mate together for more than one season. (Goodrich, Crocoll, and Senner, 1996)
Mating systems:
monogamous .
Broad-winged hawks breed between April and August, raising one brood per summer. Nest building typically begins in late April through mid-May. The male and female both build the nest, a process that takes 2 to 4 weeks. The nest is built in the main crotch of deciduous trees or on a platform of branches next to the trunk of a conifer. It is constructed of dead sticks and fresh sprigs, and lined with bark chips. Some pairs may renovate and reuse nests of other species.
The female lays 1 to 4 (usually 2 to 3) eggs at 1 to 2 day intervals. The eggs can be white, pale cream, or a little bluish. Incubation is carried out by the female and lasts 28 to 31 days. During this time, the male brings food to the female at the nest. The chicks are semi-altricial at hatching; they are covered in gray down and have open eyes. The chicks are brooded by the female for the first week or so after hatching. During the early nestling period, the male brings food to the nest, and the female tears the food into pieces and feeds it to the chicks. After 1 to 2 weeks, the female begins leaving the nest to hunt. The chicks leave the nest 5 to 6 weeks after hatching, but remain in their parents territory for another 4 to 8 weeks. They begin to capture their own prey at about 7 weeks old.
Most broad-winged hawks do not breed until they are at least two years old, though yearlings occasionally breed with an older mate.
Brood reduction (siblicide among nestlings) does occur in broad-winged hawks. However, it appears to be uncommon. In one study in New York, brood reduction occurred in 3 of 11 nests. This aspect of broad-winged hawk breeding ecology has not been well studied. (Goodrich, Crocoll, and Senner, 1996)
Key reproductive features:
iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; internal ; oviparous .
Both parents participate in nest building and feeding of the young. The female parent incubates the eggs and broods the nestlings. Meanwhile, the male provides food to the female and the nestlings. Both parents remove fecal sacs from the nest in order to keep it sanitary. (Goodrich, Crocoll, and Senner, 1996)
Parental investment:
altricial ; pre-fertilization (provisioning, protecting: female); provisioning; protecting (female); female; pre-hatching/birth (protecting: female); protecting (female); female; pre-weaning/fledging (provisioning: male, female, protecting: male, female); provisioning (male, female); male; female; protecting (male, female); male; female; pre-independence (provisioning: male, female); provisioning (male, female); male; female.
Lifespan/Longevity
Based on a study conducted between 1955 and 1979, the average expected lifespan of wild broad-winged hawks is 12 years. The oldest known wild broad-winged hawk lived at least 14 years and 4 months.
Behavior
Broad-winged hawks are solitary and territorial, except during migration. This is one of the few raptor species in North America that migrates in flocks. At the peak of migration, flocks (called kettles) can number tens of thousands of individuals. These flocks can also contain other raptors. Like many hawk species, broad-winged hawks are excellent at soaring. They make use of thermal currents during migration, allowing them to minimize the energy spent on flapping their wings.
Broad-winged hawks are territorial during the breeding season, and most likely during the winter as well. They use calls, such as their characteristic 'kee-eee' high-pitched whistle to advertise occupancy of a territory. They are active primarily during the day. (Goodrich, Crocoll, and Senner, 1996)
Home Range
The home range size of broad-winged hawks has not been studied. Breeding males appear to have larger home ranges than breeding females. (Goodrich, Crocoll, and Senner, 1996)
Communication and Perception
Broad-winged hawks use vocalizations and physical displays to communicate. There are four recognized calls that are used by broad-winged hawks. The most commonly heard is a 2- to 4- second high-pitched whistle that sounds like "kee-ee" or "peeoweee." Broad-winged hawks use calls to communicate in a variety of social situations, including territorial disputes and when communicating with a mate or offspring. (Goodrich, Crocoll, and Senner, 1996)
Food Habits
Broad-winged hawks are carnivores. Their diet changes seasonally, and consists of whichever insects, amphibians, reptiles, mammals and birds are available at any given time. During the nesting season, chipmunks, shrews and voles (genus Microtus and genus Myodes) are common in their diet, as well as frogs, lizards and nesting birds. In the winter, much of their diet consists of insects, lizards, frogs, snakes, crabs and small mammals. Mammals are eaten whole. Frogs and snakes are skinned and birds are plucked.
Broad-winged hawks hunt from a perch. Typically, they swoop down on prey to capture it on the ground.
Food caching has been observed in this species, though it is unknown how common this behavior is. ("The University of Minnesota Raptor Center and Information About Raptors", 2004; Goodrich, Crocoll, and Senner, 1996)
Primary Diet:
carnivore (eats terrestrial vertebrates); eats terrestrial vertebrates.
Animal Foods:
birds; mammals; amphibians; reptiles; insects.
Foraging Behaviors:
stores or caches food .
Predation
- raccoons (Procyon lotor)
- porcupines (Erethizon dorsatum)
- American crows (Corvus brachyrhynchos)
- black bears (Ursus americanus)
- great horned owls (Bubo virginianus)
Broad-winged hawk eggs and chicks are vulnerable to predation from avian and climbing predators, including raccoons, porcupines, American crows, black bears and great horned owls. Predation of adult broad-winged hawks has not been well documented. (Goodrich, Crocoll, and Senner, 1996)
Ecosystem Roles
Broad-winged hawks affect the local populations of the animals they eat. They also provide food for their predators.
Economic Importance for Humans: Negative
There are no known adverse effects of broad-winged hawks on humans.
As far as we know, broad-winged hawks do not harm humans in any way.
Economic Importance for Humans: Positive
Broad-winged hawks feed on insect and rodent species that may be considered pests by some humans. (Goodrich, Crocoll, and Senner, 1996)
Ways that people benefit from these animals:
controls pest population.
Conservation Status
IUCN Red List: [link]:
Least Concern.
US Migratory Bird Act: [link]:
Protected.
US Federal List: [link]:
No special status.
CITES: [link]:
Appendix II.
State of Michigan List: [link]:
No special status.
The global population of broad-winged hawks is estimated to be about 1,800,000 individuals. On a global scale, populations are believed to be declining, though data is scarce. In North America, broad-winged hawks are considered quite common.
Broad-winged hawks are protected under the U.S. Migratory Bird Act and CITES Appendix II. They are classified as a species of least concern by the IUCN. One subspecies of broad-winged hawk, the Puerto Rican broad-winged hawk (Buteo platypterus brunnescens) is protected as an endangered species under the U.S. Endangered Species Act.
Primary causes of mortality in this species include predation, trapping, shooting, and vehicle collisions. (Goodrich, Crocoll, and Senner, 1996)
For More Information
Find Buteo platypterus information at
Contributors
Alicia Ivory (author), University of Michigan.
Kari Kirschbaum (author, editor), Animal Diversity Web Staff.
