Ring-Tail Marsh Hawks (Circus hudsonius): Female and Juvenile Harriers of the Western Hemisphere

Harrier hawks are not specific to Scandinavian countries or to Scandinavian diasporas. Their name nevertheless comes from anguished depictions of Viking activities in England. The word harrier in fact dates back to the ninth century. It emerges in chronologically organized, event-oriented annals consolidated by an unknown scribe into the Anglo-Saxon Chronicle, whose publication is suspected as first occurring in England's southern half -- excluding Wales -- during the reign of Wessex's King Alfred the Great (birth 849; succession April 23, 1871; death October 26, 899). Through its etymological origins in the Old English verb hergian, it expresses the viewpoint of coastal peoples traumatized by Vikings (Old Norse for “oversea expedition”) laying waste, making war, plundering, and ravaging.

The term in its original meaning does not describe harrier hawk behavior. It does serve as an accurate designation in its evolved meaning. Since the fifteenth century, the term particularly expresses the sustained commitment to wearing down a competitor, enemy or prey through goading, harassing, and worrying. It therefore is descriptive of the harrier hawk’s patient persistence in food fights and predatory flights. For example, the harrier hawk lives in the same habitats as the short-eared owl (Asio flammeus). Each one may be accused of kleptoparasitism -- from the Greek verb κλέπτω (kleptō) for “to steal” -- in bothering one another until the predator with first claim drops the prey and flees. The harrier hawk usually prevails.

Marsh harrier hawks answer to many common names:

• Aguilucho americano, aguilucho norteño, aguilucho pálido, gavilán de ciénaga, gavilán pantanero, gavilán rastero, gavilán rastrero, and gavilán sabanero in Spanish;
• American harrier, North American harrier, northern harrier, and white-rumped harrier in English;
• Amerikaanse blauwe kiekendief in Caribbean Dutch;
• Busard d’Amérique, busard des marais, busard des roseaux, and Busard Saint-Martin d’Amérique in Caribbean French;
• Malfini savann in Caribbean creole;
• Tartaranhão-azulado in Brazilian Portuguese.

They most accurately carry the scientific name Circus hudsonius. Twenty-first century research based on scientific breakthroughs and technological advances frees them from previous subordination in 1766 by Carl Linnaeus (May 23, 1707 – January 10, 1778) to the subspecies C.c. hudsonius within the originally one-specied genus Circus cyaneus.

The scientific name acknowledges in the genus, not performability in a circus, but low-circling flight patterns (from the ancient Greek κρίκος [krikos, “ring”]) and -- in the species – location of the first specimen known to European collection (from the Latin for “relating to the Hudson [River]”). The previous species name cyaneus attributes to blue-grey coloring predominance in identification. Adult females actually convey brown-reds above, with brown-streaked buffing below and white-ringed upper tails. Adult males actually display grey breasts and uppers, with black-tipped wings and white-rumped tails. From a distance, both genders may be confused with:

• Cooper’s hawks (Accipiter cooperii);
• Northern goshawks (Accipiter gentilis);
• Rough-legged hawks (Buteo lagopus).

The marsh hawk’s back-and-forth, low-ground coursing serves as sure-fire identification. 

The term ring-tail applies only to:

• Female and male juveniles, whose eyes respectively are dark chocolate-brown and pale green-yellow;
• Female adults, whose eyes are adult male-like in lemony yellowness.

The phrase grey ghost applies only to adult males because of their spectral colors. But ghostliness characterizes all marsh harriers because of owl-like facial discs for detecting such vegetation-camouflaged prey as:

• Cotton rats;
• Field voles;
• Ground squirrels.  

Small mammals comprise 95% of marsh hawk diets. Grey ghosts and ring-tails also consider:

• Amphibians (especially frogs);
• Insects (especially cicadas, crickets, grasshoppers, katydids, locusts);
• Reptiles.

The grey ghost’s diet additionally contains:

• Ducks;
• Gamebirds;
• Passerines (especially larks, pipits, sparrows);
• Rabbits;
• Shorebirds;
• Waterfowl.

Excepting food for newborns, everything gets eaten on the ground.

Grey ghosts are the only polygynous hawks. Each male, 3 years and older, begins mating with 3 - 5 females -- aged 2 years and older -- between March and June. Within alder, cattail, and willow groves, mothers-to-be build in 1 - 2 weeks ground-level nests measuring:

• 8 - 10 inches (20.32 - 25.4 centimeters) wide by 2 - 4 inches (5.08 - 10.16 centimeters) deep interiorly;
• 16 - 24 inches (40.64 - 60.96 centimeters) wide by 4-8 inches (10.16 - 20.32 centimeters) high exteriorly.

The grass-, rush- and sedge-lined nests contain cattail, reed, and willow parts. Within 24 - 39 days, 2 to 10 unmarked blue-white eggs, sized 1.9 inches (47 millimeters) by 1.4 inches (36 millimeters), hatch if they are not devoured by:

• Badgers;
• Crows, owls, ravens;
• Raccoons;
• Red foxes;
• Skunks.

Newborns have 36 days to fledge. 

Everything about marsh harriers acknowledges length. Fledglings that survive their most virulent predator, the great horned owl (Bubo virginianus), become medium-sized raptors showcasing:

• Long, narrow faces with down-turned beaks, ruffled sound-directing feathers, and tan eyebrows;
• Long, slender bodies with long, rounded tails and long, V-held wings;
• Long, unfeathered, yellow legs with long, sharp talons on anisodactylic (3 toes forward, 1 back) feet.

Adult harriers exhibit the longest tail and wing lengths relative to body size of all North American raptors. They realize:

• Body lengths of 16 - 24 inches (40.64 - 60.96 centimeters);
• Tail lengths of 7.6 - 10.2 inches (19.30 - 25.91 centimeters);
• Weights of 10 - 14 ounces (283.49 - 396.89 grams) in males and 14 - 26 ounces (396.89 - 737.09 grams) in females;
• Wingspans of 38 - 48 inches (96.52 - 121.92 centimeters).

Except for dropping food for mothers and nestlings, male harriers absent themselves from family life. They are solitary other than:

• Competing in diving, rolling, somersaulting, swooping courtship flights;
• Foraging in groups of tens;
• Migrating in high-flying flocks, August to November and March to May.

They assert claims to territories, each of which measures about 1 square mile (2.59 square kilometers). They can sustain daily flights of 100+ miles (160.93 kilometers). They communicate by way of such calls as:

• Chek-chek-chek;
• Chuk-uk-uk-uk during courtship.

They heed such female-emitted calls as:

• Chit-it-it-it-it-et-it to sound predatory and territorial alarms;
• Piih-eh to whistle “thanks” for food drops.

Females and males may live 8 years in the wild and 16 years in captivity.

The oldest known marsh hawk fossils date back 11,000 - 40,000 years in Mexico. Harriers therefore emerge as adaptable survivors since Mesoamerica’s role as cultural and environmental conduit continues into the twenty-first century. Harrier hawks favor high-profile existences in their Western Hemisphere habitat choices of:

• Bogs, marshes, moorlands, swamps, wetlands;
• Grasslands;
• Prairies;
• Shrublands;
• Thicketlands;
• Tundra.

They closely hunt open-country prey by flying near to the ground. They impress cultivators, farmers and growers with:

• Abstention from poultry;
• Pursuit of crop-damaging insects and mammals, quail-eating predators, and reptilian pests.

Marsh hawks still keep harrier population levels sustainable despite agro-industry’s heavy pesticide usage of 1950 - 1990. May sustainability survive the twenty-first century’s ironically harrier habitat-damaging endeavors of:

• Agro-industrialists;
• Wetland diversifiers;
• Wind energy proponents. 

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Light Green - nesting area; Dark Green - resident all year; Blue - wintering area: The Engineer 2005, CC BY SA 3.0, via Wikimedia Commons @ https://en.wikipedia.org/wiki/File:Circus_cyaneus_dis.PNG

British Wildlife Centre, Newchapel, Surrey, South East England: Peter Trimming (Peter G Trimming), CC BY 2.0, via Flickr @ https://www.flickr.com/photos/55426027@N03/5692471273/

Akcja Bałtycka (Operation Baltic), University of Gdańsk: Katarzyna Stępniewska, CC BY 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Błotniak_zbożowy_2.jpg

Northern harrier (marsh hawk): Stephanie (koiart71), CC BY-ND 2.0, via Flickr @ https://www.flickr.com/photos/22334690@N07/6095780882

Northern harrier: Jean (Just chaos), CC BY 2.0, via Flickr @ https://www.flickr.com/photos/7326810@N08/1807432924

illustrations by John James Audubon (April 26, 1785-January 27, 1851); The Birds of America, Vol. I (1840), opp. p. 105: Not in copyright, via Biodiversity Heritage Library @ https://www.biodiversitylibrary.org/page/40383130

John Heinz National Wildlife Refuge at Tinicum, southeastern Pennsylvania: Susan Rachlin, Public Domain, via US Fish and Wildlife Digital Library @ https://digitalmedia.fws.gov/digital/collection/natdiglib/id/11626

"Busard Saint-Martin / Hen Harrier Circus cyaneus, male. France.": sébastien bertru, CC BY SA 2.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Circus_cyaneus,_France_1.jpg

Brazoria National Wildlife Refuge, Gulf Coast, southeastern Texas: Dan Pancamo, CC BY SA 2.0, via Flickr @ https://www.flickr.com/photos/10017367@N03/5259875890

Northern Harrier Hawk fan
Navajo Nation, Tségháhoodzání (Window Rock), northeastern Arizona: Medicinehorse7, CC BY ND 2.0, via Flickr @ https://www.flickr.com/photos/34285523@N06/3205768351/

"About 1/4 Life-size"; William Kerr Higley, ed., Birds and Nature in Natural Colors (1905), Vol. I, opp. p. 201: Public Domain, via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/36105993

Morro Bay, Central Coast, California: Kevin Cole (kevincole), CC BY SA 2.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Circus_hudsonius_female.jpg

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