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Buteo platypterusbroad-winged hawk

By Kari Kirschbaum and 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, et al., 1996; Snyder and Snyder, 1991)

Habitat

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, Information About Raptors", 2004; Goodrich, et al., 1996)

  • Range elevation
    2000 (high) m
    6561.68 (high) ft

Physical Description

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, Information About Raptors", 2004; Goodrich, et al., 1996; Snyder and Snyder, 1991)

  • Sexual Dimorphism
  • female larger
  • Range mass
    265 to 560 g
    9.34 to 19.74 oz
  • Range length
    34 to 44 cm
    13.39 to 17.32 in
  • Range wingspan
    81 to 100 cm
    31.89 to 39.37 in

Reproduction

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, et al., 1996)

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, et al., 1996)

  • Breeding interval
    Broad-winged hawks breed once yearly. They raise one brood per breeding season.
  • Breeding season
    Broad-winged hawks breed between April and August.
  • Range eggs per season
    1 to 4
  • Average eggs per season
    2
    AnAge
  • Range time to hatching
    28 to 31 days
  • Range fledging age
    5 to 6 weeks
  • Range age at sexual or reproductive maturity (female)
    1 (low) years
  • Average age at sexual or reproductive maturity (female)
    2 years
  • Range age at sexual or reproductive maturity (male)
    1 (low) years
  • Average age at sexual or reproductive maturity (male)
    2 years

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, et al., 1996)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • pre-independence
    • provisioning
      • 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.

  • Range lifespan
    Status: wild
    18.3 (high) years
  • Average lifespan
    Status: wild
    12 years
  • Average lifespan
    Status: wild
    193 months
    Bird Banding Laboratory

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, et al., 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, et al., 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, et al., 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, Information About Raptors", 2004; Goodrich, et al., 1996)

  • Primary Diet
  • carnivore
    • eats terrestrial vertebrates
  • Animal Foods
  • birds
  • mammals
  • amphibians
  • reptiles
  • insects

Predation

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, et al., 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: Positive

Broad-winged hawks feed on insect and rodent species that may be considered pests by some humans. (Goodrich, et al., 1996)

  • Positive Impacts
  • controls pest population

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.

Conservation 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, et al., 1996)

Contributors

Kari Kirschbaum (author, editor), Animal Diversity Web.

Alicia Ivory (author), University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

migratory

makes seasonal movements between breeding and wintering grounds

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

polymorphic

"many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic. Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

References

2004. "The University of Minnesota Raptor Center, Information About Raptors" (On-line). Broad-winged hawk. Accessed June 07, 1999 at www.cvm.umn.edu/depts/raptorcenter/info/Broad-wingedhawk/.

Goodrich, L., S. Crocoll, S. Senner. 1996. Broad-winged hawk (Buteo platypterus). Pp. 1-28 in A Poole, F Gill, eds. The Birds of North America, Vol. 218. Philadelphia, PA: The Academy of Natural Sciences and Washington, D.C.: The American Ornithologist's Union.

Snyder, N., H. Snyder. 1991. Birds of Prey: Natural History and Conservation of North American Raptors. Stillwater, MN: Voyageur Press.

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