MARSH HAWK

INDEX:
    WHAT IS A MARSH HAWK?
    WHAT IS ITS ROLE IN THE GREAT SALT LAKE MARSHES?
    WHERE DO THEY LIVE?
    HOW DO YOU IDENTIFY THE MARSH HAWK?
    MATING AND NESTING
    HOW DO I FIND OUT MORE ABOUT OTHER GREAT SALT LAKE RAPTORS?

 
 female harrier

WHAT IS A MARSH HAWK?

      The Northern harrier, more commonly called the marsh hawk, belongs to the family

Accipitridae, along with kites, accipiters, and eagles.  The genus and species of the harrier is

Circus cyaneus. (See above image)
 

WHAT IS ITS ROLE IN THE GREAT SALT LAKE MARSHES?

     Harriers of the Great Salt Lake ecosystem receive energy and nutrients necessary for their

survival by feeding on certain organisms around the Great Salt Lake.  One of the most important

food sources for the harrier is the meadow vole, which lives in the grasslands around the lake, and

is there year-round.   See meadow vole.    
 
    Small birds are also an important food source for the harrier.  The marsh hawk often feeds on

migratory birds of the Great Salt Lake.  One of the more common of these migratory birds is the

Wilson's Phalarope, which arrives in Utah around mid-June, and leaves late July and into August;

thus, providing food for the harrier for these few summer months.  Another common migratory bird

that provides food for the harrier is the Eared Grebe, which arrives to the Great Salt Lake around

the end of June, and leaves during the winter months.

    Other birds eaten by the harrier include waterfowl, such as Cinnamon and Green winged Teal,

and Avocets.  Refer back to Great Salt Lake food web in the introduction.
 

WHERE DO THEY LIVE?

     Marsh hawks are found in marshes, meadows, and fields.  They are common residents of

Utah, and many remain year-round; although, migration takes place in the northern part of the

range in North America.  Northern harriers breed from Alaska through Canada and the northern

half of the United States; and winter from the middle United States into Mexico.  Those that

migrate leave Utah during November, and arrive again in March or April.  During spring and

summer, harriers eat approximately 12% of their body weight per day.  During the colder seasons,

they eat approximately 19% of their body weight per day.  Hunting for these birds consists mainly

of small rodents and birds, over two thirds of their diet. Insects, snakes, and frogs are also

occasionally eaten. Harriers sometimes feed on carrion, although they prefer live prey.
 

HOW DO YOU IDENTIFY THE MARSH HAWK?

     It is a slim hawk with long wings, tail, and legs, and also a small head.  It is generally 17 1/2 to

24 inches in length, with a wingspan of 42 to 54 inches.  Distinctive features of the marsh hawk

include: a white rump patch; an owl like face; and the low quartering flight over fields and marshes,

with the wings held in a shallow "V" position.

male harrier
    Sexual dimorphism of this bird is pretty distinguishable.  Adult males are a light gray color with

white under parts, and some reddish spotting.  They also have black wing tips.  Adult females are

brown with some brownish streaks on the under parts. They are also larger than the males.  The

males weigh approximately 472 grams(1.04 lbs.),while the females weigh approximately 570

grams(1.25 lbs.).   Juveniles closely resemble the female but are cinnamon on the under parts;

however, this color fades by mid-winter.

  juvenile harrier

MATING AND NESTING

        The nest of the marsh hawk consists of sticks and grasses, on the ground or on low

vegetation.  Both birds participate in nest construction, but brooding is done by the female. Mating

takes place in Utah around early April, and nesting begins by early May.  The distinctive courtship

flight of the male during March and April is said to be spectacular.  The flight consists of dives from

50 to 100 feet, swooping near the ground and climbing again to repeat the process.  The apex of

the climb is usually terminated by a roll or somersault before the next dive.  See  northern harrier.

Three to nine eggs are laid in the nest, on average five.  The eggs are white, sometimes splotched

with brown.  The incubation period is 31 days. Before the young can fly, they leave the nest and

scatter throughout the surrounding vegetation.  Age at first flight is 30 to 35 days.
 
HOW DO I FIND OUT MORE ABOUT OTHER GREAT SALT LAKE RAPTORS?

    To find more information on other Great Salt Lake raptors, (which include the Bald and Golden

Eagle, the Peregrine Falcon, the American Kestrel, and the Red-tail Hawk), as well as other birds,

visit these sites:  

http://www.raptor.cvm.umn.edu/newwebdev/raptor/rfacts/rfacts.htmlhttp://www.hawkwatch.org/http://www.suttoncenter.org/other.html .
 
 
 
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 Northern Harrier
 Drawing by:  Nghia Nguyen, 1998
 

REFERENCES

Peterson, Roger Tory; A Field Guide to Western Birds; Riverside Press, 1961.

URL:  Gothard, Greg;  (http://home.sprynet.com/sprynet/chip_tg/harr.htm).

URL:  Wetnet-Northern Harrier;  (http://www.glo.state.tx.us/res_mgmt/wetnet/species/harrier.html).

URL:  Conover, Kirsten; Simon-Brown, Viviane; The High Desert Museum;  (http://www.highdesert.org/birds6.htm).

URL:  Grassland Animals-Meadow Vole;  (http://www.mobot.org/pfg/diverse/biomes/grasslnd/animals/vole.htm).

URL:  The Raptor Center at the University of Minnesota; Raptor Facts-Northern Harrier;  (http://www.raptor.cvm.umn.edu/newwebdev/raptor/rfacts/nharr.html).