The common black-hawk (Buteogallus anthracinus) is a widespread raptor found throughout much of the Americas. This medium-sized hawk inhabits a variety of wooded habitats and can often be seen soaring over open areas looking for prey. One of the defining features of the common black-hawk is its broad wingspan, which allows it to effortlessly ride thermals while hunting.
Typical Wingspan Measurements
Most sources report the wingspan of the common black-hawk as approximately 3.3-4.3 feet (1-1.3 meters). More specifically, the typical measurements are:
- Males: 3.3-3.7 feet (1-1.13 m)
- Females: 3.6-4.3 feet (1.1-1.3 m)
Females are slightly larger than males, which is common among birds of prey. The largest wingspans at the upper end of the range may belong to subspecies found in the southern parts of the range, such as B. a. anthracinus and B. a. plagiatus, which average larger than northern subspecies.
Wingspan Comparisons
The common black-hawk has a medium-sized wingspan compared to other hawks and eagles:
- Smaller than large eagles like the golden eagle (6.6-7.5 feet / 2-2.3 m)
- Larger than the sharp-shinned hawk (1.5-2 feet / 0.5-0.6 m)
- Similar to other Buteogallus hawks like the great black hawk (3.3-4.2 feet / 1-1.3 m)
- Smaller than the Harris’s hawk (3.3-4.3 feet / 1-1.3 m), which has the widest wingspan of all raptors relative to its body length
Overall, the common black-hawk has a medium to large wingspan compared to other buteos and Accipiters. It’s not the largest by any means, but its wings are broad enough to allow specialized hunting techniques like thermal soaring.
Flight Capabilities
The wide wingspan of the common black-hawk gives it versatility in flight and hunting styles. Some key capabilities include:
- Soaring – Broad wings work like aircraft wings to ride warm updrafts and thermals high into the sky with little effort. This allows wide-ranging searches for prey.
- Maneuverability – The wings enable tight turns and sudden movements to grab prey while cruising over open areas.
- Speed – These hawks are impressively fast in open areas when motivated, using their wings for rapid straight-line flight.
- Acceleration – Their muscular flight muscles and low wing loading (ratio of body weight to wing area) allows very quick acceleration.
- Takeoff – Their wings give them the power needed for straight vertical takeoff from perches when pursuing prey.
In woodland habitats, the broad wings act like maneuverable oars to zig and zag through dense vegetation. Overall, the common black-hawk’s diverse hunting strategies rely on its medium to long, broad wings.
Wing Shape
The wings of common black-hawks have a rectangular shape when fully extended. The wing chord (distance from leading to trailing edge) is fairly consistent from the shoulder to the wingtip, giving it an overall rectangular silhouette.
The wingtips are slightly tapered but do not come to a point. This provides balance between speed, maneuverability, and soaring ability. The rectangular shape gives the wings both aerodynamic properties for cruising, as well as lift properties to soar upwards.
Wing Loading
Wing loading refers to the ratio between a bird’s weight and its wing area. It provides an indication of flight capabilities. Common black-hawks have a wing loading of approximately 0.2 lb/ft2 (10 N/m2).
This low wing loading allows easy takeoff, good maneuverability, and easy soaring. For comparison, turkey vultures have an extremely low wing loading of 0.064 lb/ft2 (3.1 N/m2) which enhances their soaring. Falcons have a higher wing loading around 0.4 lb/ft2 (20 N/m2) which gives fast diving speeds.
So the common black-hawk’s intermediate wing loading gives it versatility between soaring efficiency and high-speed flapping flight when chasing prey.
Wing Position at Rest
When perching, common black-hawks tend to hold their wings loosely folded against their bodies. The wings are held horizontally against the body, sometimes appearing like a mantle over the hawk’s back.
Unlike smaller hawks that hold their wings tightly folded making a neat silhouette, the larger wings of the common black-hawk appear more casually folded around the sides and across the back. However, the wings can open quickly to catch rising thermals.
Wing Molt
Like all birds, common black-hawks molt and replace their wing feathers periodically. This is essential for maintaining healthy, aerodynamic feathers.
In common black-hawks, the molt sequence begins in early spring with the shedding of the outermost primary feathers. This descends in sequence over the rest of the wing through summer and fall. The molt occurs gradually, so the hawk never sheds all wing feathers simultaneously and is never left flightless.
By late fall, the molt is usually complete. The new set of flight feathers will last until the next molt sequence begins in spring. Synchronizing molt with seasons helps ensure the hawk has strong flight feathers just before the higher energy demands of spring breeding and summer hunting.
Juvenile Wings
Juvenile common black-hawks have a similar wingspan to adults. However, their flight feathers are often somewhat more tattered from the stresses of early flight practice.
Young fledglings will also retain some downy feathering, especially around the wing edges. This is gradually molted and replaced with adult-like plumage through its first year of life.
Despite their somewhat unkempt appearance, juvenile hawks quickly gain strong flight capabilities under the tutelage of their parents.
Range of Habitats
Common black-hawks occupy a variety of habitats across their large range, including:
- Tropical rainforests
- Temperate broadleaf forests
- Coniferous forests
- Forest edges and clearings
- Woodland savannahs
- Marshes and wetlands
Their diverse habitat range, made possible by their wing capabilities, is an important reason for their wide distribution across two continents.
Diet
The common black-hawk uses its wingspan and flight capabilities to hunt a variety of prey, including:
- Snakes
- Lizards
- Small mammals like squirrels and rats
- Large insects
- Amphibians like frogs
- Other birds
Its broad hunting range includes cruising over wetlands, scanning from a forest perch, swooping through dense woods, and soaring high over fields.
Breeding
The common black-hawk’s large wingspan aids in securing breeding territories and food for its mate and offspring. Courting males perform circular territorial flights and dramatic dives to impress females.
Once breeding, the female depends on her wingspan to hunt prey to feed the nestlings while the male defends the territory. The male also uses his flight abilities to hunt and bring food to his incubating mate. So both sexes rely heavily on their flight capabilities during breeding season.
Migration
Some northern populations of common black-hawks migrate short distances of up to a few hundred miles. Their broad wings allow them to make these seasonal movements fairly effortlessly.
However, most populations are non-migratory and remain resident year-round. The wings provide the mobility needed to secure territories and hunt prey even in the lean winter months.
Adaptations for Flight
Common black-hawks have several adaptations that allow powerful and efficient flight:
- Large pectoral muscles – The breast muscles that power the wings are very large and strong.
- Lightweight skeleton – The bones are light yet sturdy to minimize weight.
- Dense feathers – The feathers have a streamlined structure for smooth airflow.
- Aerodynamic body – The tapered body and narrow tail reduce drag.
- Excellent eyesight – Their vision aids hunting from great heights.
Together, these attributes allow common black-hawks to utilize their impressive wingspan to the fullest.
Flying Methods
Common black-hawks employ a variety of flight techniques thanks to their versatile wings, including:
- Flapping – Powerful wingbeats for active hunting and chasing prey.
- Soaring – Wings held stiffly to ride thermal updrafts and cover large areas with minimal effort.
- Gliding – Wings held outstretched and motionless to descend from heights.
- Kiting – Flapping while facing into the wind to hover stationary above one spot.
- Cruising – Relaxed flapping along a straight course for migration or moving between hunting spots.
This variety of flight methods allows common black-hawks to successfully inhabit their widespread range.
Wing Tags
Ornithologists who study common black-hawks sometimes attach numbered tags to the patagial wing tags to track individual hawks. These provide information on migration routes, lifespan, territories, and population health.
The patagial tag is a stretchy tissue on the front edge of the wing that can be gently clamped and marked without harming the bird. When appropriately sized, tags do not impede the hawk’s flight at all.
Lifespan
In the wild, common black-hawks can live 12-15 years on average. With such a long lifespan, the wings must withstand many years of environmental stresses and wear.
Molting and replacement of feathers is essential for maintaining strong flight performance season after season throughout the bird’s life. In captivity with ideal conditions, Lifespans of 18-25 years have been recorded.
Wingspan Records
Among common black-hawks, some maximum wingspan measurements that have been recorded are:
- Male: 3.7 feet (1.13 m)
- Female: 4.5 feet (1.37 m)
These represent the extremes of the range, well above average measurements. There are anecdotal reports of female hawks with wingspans up to 5 feet (1.5 m), although these are very rare cases.
Identification
The common black-hawk’s distinctive wingspan and flight silhouette aids in identifying the bird at a distance:
- Rectangular, broad wings held flat while soaring
- Small head relative to long wings
- Slow, steady wingbeats interspersed with gliding while hunting
- Dark plumage on undersides of flight feathers
These identification points distinguish them from smaller, more compact hawks, as well as from eagles who soar on flat wings held in a slight upturned dihedral.
Conservation Status
The common black-hawk has a very large range and global population estimated at 100,000 to 1 million birds. For these reasons, it is classified as Least Concern on the IUCN Red List.
However, some local populations are in decline, especially in the northern end of the range. Loss of forests is reducing habitat and prey availability. Ongoing protection of wooded environments will be important for the long-term health of common black-hawk populations.
Summary
With a typical wingspan of 3.3-4.3 feet (1-1.3 m), the common black-hawk has broad, rectangular wings well suited to soaring, maneuvering through dense habitats, migrating, and hunting diverse prey. Compared to other raptors, it is medium-large in size but smaller than many eagles. The wings provide great agility and speed as well as slow soaring flight to utilize thermals and energy-efficiently patrol territories. Overall, the common black-hawk is aptly named for its dark plumage and its exceptionally capable black wings.