Introduction / Taxonomy
The Sharp-shinned Hawk (Accipiter straitus) is species is a member of the genus Accipiter which is a group of raptors that includes a total of 51 species. Member of this genus are generally slender birds that have short, broad, rounded wings and a long tail which helps them maneuver in flight. They have long legs, toes, and talons which they used to kill their prey.
Member of this genus also have a sharp, hooked bill used in feeding. They often hunt by ambushing their prey, which are mainly small birds and mammals, that they capture after a short chase. The typical flight pattern is a series of flaps followed by a short glide. They are commonly found in wooded or shrubby areas.
The Sharp-shinned Hawk male is the smallest hawk in the USA. Females are approximately one-third larger than males.
The Sharp-shinned Hawk has 8 subspecies:
- A. s. velox breeds across North America from Alaska and northern Canada south to the southern U.S.A.
- A. s. perobscurus is a resident of the Queen Charlotte Islands.
- A. s. suttoni breeds from the most southern area of New Mexico, U.S.A. south to central Mexico.
- A. s. madrensis is found in Guerrero in the Sierra Madre del Sur, in Mexico, where it is considered an endemic.
- A. s. fingillodies is a resident subspecies in Cuba.
- A. s. stratus is a resident subspecies in Hispaniola.
- A. s. venator is a resident subspecies in Puerto Rico.
- A. s. chionogaster is a resident subspecies from Chiapas, Mexico to Nicaragua and is sometimes considered to be a separate species.
How to Identify a Sharp-Shinned Hawk
Sharp-shinned Hawk are small forest hawks. They have relatively short, rounded wings and a long, straight tail that is squared off at the tip, or even notched. They have small beaks and large eyes, relative to the size of their small rounded heads. Their legs are long and narrow (hence their name) with large, long toes and talons. Adult birds are blackish-blue on the top of the head, blue-grey on the back and on the upper surface of the wings.
Adult bird undersides are white with fine orange barring running horizontally across the breast and belly, and white feathers near the legs. Juvenile birds are brown on the top of the head, on the back, and on the upper surface of the wings. Juvenile bird undersides are white with dense, dark brown streaking running vertically down the breast and belly.
When in flight, Sharp-shinned Hawks beat their wings in a characteristic pattern of flap-flap-glide, flap-flap-glide. Since these hawks are so small, they are very buoyant in the air and are easily shifted around, mid-air, by wind currents.
Where Do Sharp-Shinned Hawks Live: Habitat
Breeds is forested areas. This includes the northern boreal forest of Canada, many forest and woodland types in temperate North America, mountainous uplands in Central and South America, and can also include arid and humid tropical lowland forests. Generally, forest edges and clearings, watersides, and broken or patchwork woodlands are preferred over areas of dense forest. Elevation ranges from sea level to about 3,700 meters. During migration, this species can be found at any elevation.
Sharp-Shinned Hawk Diet and Feeding
This species of hawk eats almost exclusively birds. Bird prey species range from hummingbirds to small pigeons and doves. In the breeding season, this hawk will take nestlings of other birds. Occasionally, small mammals are taken. Foraging involves still hunting from a concealed perch, ambush visits to bird feeders and known roosting sites, or transect flights along the transition zones between habitats such as where a forest and grassland meet or along a hedgerow.
This species relays on surprise followed by relatively short chases with the hawk attempting to grab its prey before the prey animal can find cover.
Female birds, being larger, tend to take larger prey species, while the male birds, being smaller, tend to focus on smaller prey species. In this way, members of a pair avoid directly competing with one another for prey and are able to maximize the diversity of prey species they relay on and are able to provide to their young during the breeding season.
Sharp-Shinned Hawk Breeding
Breeding begins later at higher latitudes and later at lower latitudes. In Alaska and northern Canada, breeding begins in May-August. In the southern USA, breeding begins in from March to July. In the Caribbean, breeding begins in January. In South America, little seasonality is shown.
Sharp-Shinned Hawk Nesting
Nests are small, bulky masses of sticks that are often lined with strips of bark and leaves. Nests are generally built from 4 to 20 meters above the ground at a branch fork or near the central trunk of a tree. Clutches range from 1 to 6 eggs but usually include from 4 to 5. Incubation lasts from 30 to 35 days, and is conducted almost exclusively by the female bird while the male provides her with food.
A baby hawk is called an “eyas.” Young fledge from the nest about 21 to 27 days after hatching at which point the young birds usually remain in branches near the nest until they grow in all their feathers which generally takes another 10 to 15 days. Young at this stage of development are called “branchers.”
Sharp-Shinned Hawk Eggs
Eggs are generally laid shortly after the nest building is complete. One egg is laid every other day until the clutch is complete. The eggs are similar in shape to chicken eggs, though a bit smaller. They are usually smooth, white, and oval. Less commonly, Sharp-shinned Hawk eggs can sometimes have brown speckling and some can have a bluish tint.
Sharp-Shinned Hawk Population
According to the North American Breeding Bird Survey, Sharp-shinned Hawk population numbers have remained relatively stable between 1966 and 2019. the most accurate populations estimates that are made from yearly migration counts across the range of this species. This is due to their solitary and elusive nature and the deep-forest habitats where they breed which combine make large scale surveying and data collection difficult. The global breeding population is estimated to be about 1 million individuals.
Is the Sharp-Shinned Hawk Endangered?
This species is overall of low conservation concern due to the relatively stable population numbers that have been measured over the past several decades. However, the Puerto Rican Sharp-shinned Hawk is federally listed as Endangered. This small population has been severely effected by large hurricanes that have swept over the island and caused significant deforestation.
As the size and intensity of hurricanes increase due to climate change, this and other island populations of Sharp-shinned Hawks, will likely be ever more impacted.
Another impact that Sharp-shinned Hawks face is related to their breeding habitats of dense stands of trees. This means that their population is intertwined with the persistence of wooded wilderness. As habitat fragmentation and deforestation increase, Sharp-shinned Hawk populations will likely be impacted.
Like many other species of birds of prey, Sharp-shinned Hawks suffered breeding failure when the pesticide DDT was in wide use in North America. Some carry high levels of this pesticide in their bodies even today which could be a result of the bird prey species that they eat spending significant amounts of time in South America during the non-breeding season.
DDT is still used in many South American countries and so these prey species may absorb the pesticide and cause secondary exposure to Sharp-shinned Hawks when the hawks eat the contaminated prey birds.
Sharp-Shinned Hawk Habits
These hawks are found in forests and forest edges where they wait in ambush. Once a prey presents itself as a target, the hawk bursts out of hiding in a high speed, high maneuverability, chase. These chases usually do not last long and either the hawk is successful or the prey species escapes. Sharp-shinned Hawks do sometimes hunt birds at feeders, and the spread of backyard bird feeding may have helped populations of Sharp-shinned Hawks or allowed them to spend winters farther north than they used to.
Sharp-Shinned Hawk Predators
Sharp-shinned Hawks were once killed as vermin by bird enthusiasts trying to protect songbirds. This practice has largely stopped partly due to better understanding that a healthy predator population actually helps keep prey populations healthy, and partly due to the passing of laws and ratifying of treaties, in and between various countries such as the Endangered Species Act in the USA and the Migratory Bird Treaty Act between Canada, the USA, and Mexica.
These laws and treaties have the specific goal of protecting many different bird species, including the Sharp-shinned Hawk.
Sharp-Shinned Hawk Lifespan
Sharp-shinned Hawks tend to live an average of about three years in the wild. Individuals can live up to ten years.
Answer: Sharp-shinned Hawks (SSHA) and Cooper’s Hawks (COHA) are very similar in many ways, but there are differences. Some of these differences are listed below. These differences can be used to distinguish between individuals of these two species, but may require some practice to observe.
This list is not exhaustive as other differences to exist, but these are some of the most useful and observable.
• Body Size: SSHA are roughly robin-sized, COHA are roughly crow-sized.
• Head: SSHA have smaller heads which are less prominently visible while in flight, COHA have larger heads that are more prominently visible while in flight.
• Eye Size: The eye of a SSHA is large in relation to the size of the head which can give this species a bug-eyed look, the eye of a COHA is smaller in relation to the size of the head.
• Adult Neck Coloration: The dark coloring of the top of the head on a SSHA extends down the back of the neck and merges with the the color of the back, the dark coloring in the top of the head of a COHA stops at the back of the head while the neck is the reddish-orange of the face and cheek.
• Tail: The tip of the tail of a SSHA is squared off, the tip of the tail of a COHA is rounded.
• Flight Behavior: The flapping and gliding pattern of a SSHA is faster (flapflapglide)
Answer: No. The Sharp-shinned hawk is the smallest hawk in North America, but the American Kestrel is a species of falcon, and is the smallest raptor (or bird of prey) found in North America.
Answer: The lower leg of a Sharp-shinned Hawk is especially narrow and flattened, side to side. This gives the “shin bones” a very thin and narrow edge, front and back. This trait is where the name of this hawk comes from.
Ferguson-Lees, J. and D. A. Christie. (2001). Raptors of the World. Houghton Mifflin Company, New York, NY, USA.
Johnsgard, P. A. (1990). Hawks, eagles, and falcons of North America. Smithsonian Institution Press, Washington D.C., USA.
Pyle, P. (1957). Identification Guide to North American Birds : a Compendium of Information on Identifying, Ageing, and Sexing “near-Passerines” and Passerines in the Hand. Slate Creek Press, Bolinas, CA, USA.
Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.
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