The Northern Harrier (Circus hudsonius) is a medium-sized raptor found throughout North America. The males, known as the “gray ghost” due to their striking gray and white plumage, are smaller than the brown females. Let’s take a closer look at the dimensions of male Northern Harriers.
Wingspan
The wingspan is the distance between the tip of one wing to the tip of the other when the wings are fully outstretched. For male Northern Harriers, the average wingspan ranges from 110-145 cm (43-57 in). Their long, slender wings allow them to skillfully maneuver through open habitats like marshes and fields when hunting.
Body Length
From the tip of the beak to the end of the tail, male Northern Harriers measure approximately 33-48 cm (13-19 in) in body length. Their tails make up around half of their total body length. The elongated tail feathers help provide stability and assist with aerial acrobatics.
Weight
These slim raptors weigh 330-700 g (11.6-24.7 oz) on average. Some key factors that influence their weight include age, time of year, and food availability. Males are typically about 20% lighter than females of the species.
Wing Loading
Wing loading measures the ratio of body mass to wing area. It provides an indication of how much lift a bird’s wings need to produce to stay aloft. Male Northern Harriers have a wing loading of around 4 g/cm2 (0.8 oz/in2). Their light wing loading allows them to fly slowly and hover low over vegetation when hunting.
Wing Shape
Northern Harriers have long, broad wings ideal for soaring and gliding low over open country. The wings are tapered and narrow at the tips, which reduces drag and allows for high maneuverability. The wings are positioned further forward on the body compared to other raptors, giving the harriers their distinctive flight profile.
Leg Length
These raptors have relatively long legs compared to other hawks and falcons. Their tarsus length (lower leg) averages around 7.5-9 cm (3-3.5 in). Long legs combined with their owl-like facial disk help them locate prey by sound in tall grass or marshes.
Foot Size
Male Northern Harriers have feet about 5-7 cm (2-2.8 in) long from the back of the heel to the tip of the middle toe claw. Their feet help them grasp and carry prey items, and also aid in maneuvering on the ground.
Beak Size
They have a hooked, raptor-like beak that measures approximately 2-3 cm (0.8-1.2 in) long from the tip to the base. Their beak helps them tear into prey and eat smaller items like rodents whole.
Conclusion
In summary, male Northern Harriers are medium-sized raptors with a wingspan of about 110-145 cm (43-57 in), body length around 33-48 cm (13-19 in), and weight from 330-700 g (11.6-24.7 oz). Key features include long, slender wings for agile flight, an owl-like facial disk, relatively long legs, and a sharp hooked beak. Their lightweight, aerodynamic build allows them to hunt very effectively over open areas.
Size Comparisons
It can be helpful to compare the size of male Northern Harriers to other familiar birds:
Crows
Crows are stockier with shorter wings and tails than Northern Harriers. An American Crow measures around 40-50 cm (16-20 in) long with a wingspan of about 85-100 cm (33-39 in). Crows are heavier, weighing 300-600 g (10.6-21.2 oz).
Red-tailed Hawks
Red-tailed Hawks are more robust and nearly twice as heavy as male Northern Harriers. They have shorter wings spanning about 110-145 cm (43-57 in). Length ranges from 45-65 cm (17.7-25.6 in) and weight from 680-1400 g (1.5-3.1 lbs).
Great Horned Owls
The chunky, powerful Great Horned Owl dwarfs the slender Northern Harrier. Great Horneds have a wingspan of approximately 110-150 cm (43-59 in) but are much heavier at 1000-3000 g (2.2-6.6 lbs). They have a stockier body 45-63 cm (17.7-24.8 in) long.
Male vs Female Size
Female Northern Harriers are distinctly larger and heavier than the males. Here’s a comparison of their average dimensions:
Measurement | Male | Female |
---|---|---|
Wingspan | 110-145 cm (43-57 in) | 125-150 cm (49-59 in) |
Body Length | 33-48 cm (13-19 in) | 40-58 cm (15.7-22.8 in) |
Weight | 330-700 g (11.6-24.7 oz) | 480-1300 g (17-46 oz) |
The size difference between males and females is known as sexual dimorphism. The larger female harriers are able to incubate eggs and also help defend the nest if needed.
Juvenile Size
Northern Harrier chicks grow rapidly after hatching. Here is how their size progresses with age:
Age | Wingspan | Weight |
---|---|---|
Hatching | Around 5 cm (2 in) | 35-55 g (1.2-1.9 oz) |
10 days old | About 30 cm (12 in) | 150-200 g (5.3-7 oz) |
30 days old | Around 75 cm (29.5 in) | 500-700 g (17.6-24.7 oz) |
Young harriers reach adult size after 8-10 weeks. They learn to fly around 40 days of age and hunt on their own at 60-70 days old.
Factors Influencing Size
Several factors can contribute to size variations among individual male Northern Harriers:
Age
Younger birds are typically smaller. Yearlings may still be finishing growing, while old birds can lose some mass.
Geography
Geographic variations exist across populations. Northern birds are generally larger than Southern ones.
Prey Availability
Abundant prey allows harriers to maintain higher body weights.
Time of Year
Harriers lose body fat during migration and can weigh less outside the breeding season.
Parasites and Disease
Illnesses and external/internal parasites can negatively impact size and condition.
Pollutants
Environmental toxins like pesticides may interfere with growth and development.
Uses for Size Information
Knowing the typical dimensions of male Northern Harriers has several applications:
Field Identification
Size clues assist birdwatchers with identifying harriers in flight or distinguishing them from other raptors.
Tracking Growth
Biologists use measurements to monitor development of nestlings andCondition
determine if the birds are getting adequate food.
Assessing Condition
Weight data helps rehabilitators evaluate rehabilitation progress and health issues for injured harriers.
Research
Scientists may study geographical size variations to understand effects of factors like climate and urbanization on harrier populations.
Falconry
Falconers must consider size to ensure proper housing, equipment, and care for captive harriers.
Conclusion
The male Northern Harrier is a medium-sized raptor with unique adaptations for hunting over open country. Average dimensions include a wingspan of 110-145 cm, length of 33-48 cm, and weight around 330-700 g. Females run larger at 125-150 cm wingspan and 480-1300 g weight. Juveniles hatch small but grow rapidly to adult size in 8-10 weeks. While geography, age, and other factors create some variability, being familiar with typical harrier sizes aids in identification, care, and research for these graceful hunters.