Short Eared Owl

Maximum longevity: 21.8 years Observations: There are anecdotal reports of animals living up to 28 years but these have not been confirmed.

Short-eared owls are vulnerable primarily to mammalian predation due to the type of open habitat they occupy and their ground nesting habit. Short-eared owls fly fast and directly at an intruder, pulling up and presenting their talons at the last moment. They often use thermal updrafts during skirmishes and rise vertically, chasing and interacting with intruders. They may scream, whine, and distract predators on eggs or nestlings by pretending to have a broken wing.

Known Predators:

• northern goshawks (Accipiter gentilis)
• peregrine falcons (Falco peregrinus)
• gyrfalcons (Falco rusticolus)
• red-tailed hawks (Buteo jamaicensis)
• great horned owls (Bubo virginianus)
• snowy owls (Nyctea scandiaca)
• bald eagles (Haliaeetus leucocephalus)
• northern harriers (Circus cyaneus)
• common ravens (Corvus corax)
• herring gulls (Larus argentatus)

Short-eared owls range in length from 340 to 415 mm in males (mean 373 mm) and 340 to 423 mm in females (mean 382 mm). Wing length is from 279 to 307 mm in males and 267 to 314 mm in females. Wingspan is estimated at 950 to 1100 mm. Males and females are not easily distinguishable from each other externally, but females are usually slightly larger. Their feathers are yellow-white and dark brown; parts of the head and especially the legs and flanks are white. Individuals vary considerably in colors. The right and left ears occupy different vertical positions on the sides of their head, but the size and shape of the two ears are the same. (Holt and Leasure, 1993; Martin, 1990; Pearson, 1936)

Range mass: 206 to 475 g.

Average mass: 347 g.

Range length: 340 to 423 mm.

Range wingspan: 950 to 1100 mm.

Average basal metabolic rate: 313.375 cm3.O2/g/hr.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: female larger

Records are limited, but the longevity record for a wild short-eared owl is 4 yrs, 2 months. Causes of mortality include occasionally being hit by cars and airplanes, or being shot or trapped.

Range lifespan
Status: wild: 21.8 (high) years.

Average lifespan
Status: wild: 53 months.

One of the world's most widely distributed owls, Asio flammeus can be found throughout much of North America and Eurasia. These owls prefer to live in marshes and bogs; they inhabit open, treeless areas. Their hunting and nesting habits make them well suited to relatively flat land. This species is migratory but uses relatively similar habitats during summer and winter. Short-eared owls have specialized eating habits and tend to stay where they can find ample food. They will leave an area to find preferred prey rather than eat other animals. Nests are usually located on dry sites and in open country supporting small mammals such as voles and lemmings.

(Martin, 1990; Sparks and Soper, 1989; Pearson, 1936)

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: savanna or grassland ; forest

Wetlands: marsh ; swamp ; bog

Other Habitat Features: agricultural

Short-eared owls are one of the world's most widely distributed owls. They inhabit all of North and South America; this area includes the coast of the Arctic Ocean to Pantagonia. Short-eared owls can also be found on every continent except Australia and Antarctica. (Granlund et al., 1994; Welty, 1975; Pearson, 1936)

Biogeographic Regions: nearctic (Native ); palearctic (Native ); oriental (Native ); ethiopian (Native ); neotropical (Native )

Other Geographic Terms: cosmopolitan

Short-eared owls prey primarily on voles, mice, and other small mammals. Their strong talons and sharp beak make them well adapted to 'picking up' their food while in flight. These owls may utilize a 'perch-and-pounce' hunting method if there is an adequate perching point available. Otherwise, they hunt by flying two meters above the ground in a regular, slow manner. Short-eared owls rely mainly on auditory clues; using these alone, they can catch prey that is under continuous grass cover. (Martin, 1990 and Pearson, 1936)

Animal Foods: birds; mammals

Primary Diet: carnivore (Eats terrestrial vertebrates)

Short-eared owls are important predators on populations of many different types of small mammals and birds.

Short-eared owls help manage animals that humans consider to be pests; a large portion of their diet is small rodents, such as mice and voles. In areas where small mammals can reach plague numbers, short-eared owls capitalize on the opportunity and settle in large numbers. (Sparks and Soper, 1989 and Pearson, 1936)

Positive Impacts: controls pest population

There are no known negative effects of short-eared owls on humans.

Due to their wide distribution, short-eared owls are not a federally endangered species; however, in the Great Lakes region of the United States, conditions are worse. This species is threatened by the diminishing area of marshes, bogs, and open grasslands. Nesting habits and nomadism make this species particularly vulnerable to habitat loss during any season. Due to these factors, short-eared owls are endangered in Michigan, Illinois, and Pennsylvania. They are also threatened in Minnesota and of special concern in Indiana and Ohio. They are among the rarest nesting owls in Michigan. There are no major efforts to help them recover in these areas. (Granlund et al., 1994)

US Migratory Bird Act: protected

US Federal List: no special status

CITES: appendix ii

State of Michigan List: endangered

IUCN Red List of Threatened Species: least concern

Short-eared owl nestlings give high pitched calls from within the egg, and from hatching until they are about 7 days old. These are probably begging calls or perhaps expressing discomfort. The vocal pitch changes at about 7 days and becomes lower. Adults sometimes direct calls at human territorial intruders. Both males and females bark, scream, whine, and give broken wing distraction displays to defend the nest and young from potential threats. In late February and March, territorial songs are sung. (Holt and Leasure, 1993)

Short-eared owls have keen vision, especially in low light. They also use their excellent sense of hearing to help locate and capture prey.

Communication Channels: visual ; acoustic

Perception Channels: visual ; tactile ; acoustic ; chemical

The difficulty of owl reproduction lies in their usually individualistic habits; a great amount of the effort goes into learning mutual recognition as mating partners rather than prey or predator. They even have some difficulty identifying the gender of prospective mates from a distance. Male short-eared owls use an aerial display that includes wing clapping to alert the female of his presence and sex. Males also may offer food to females; this prevents females from considering the male as food.

Pair formation begins in mid-February and continues through June. Breeding usually begins in April. Short-eared owls are reported to also raise a second brood although this is not confirmed. To attract females, males perform sky dancing displays, day or night. The sky dance consists of song accompanied by aerial acrobatics. Short-eared owls are generally thought to be monogamous; however, the pair bond probably does not last beyond the breeding season. (Holt and Leasure, 1993)

Mating System: monogamous

After sufficient time and caution has been taken, the male mounts the female. One observer reported that copulation took 4 seconds, after which the male and female flew in different directions. Breeding usually takes place while in their summer habitat, but they may breed in their wintering area if food is plentiful. Short-eared owls nest on the ground in protection provided by tall grasses; they often return to the same nests. Each nest contains 4 to 7 white, unspotted eggs. The eggs have an average incubation of 21 days. Nestlings have been known to prey on their smaller nest mates. The young usually disperse from the nest when they are about 14 to 17 days old. They are independent 1 to 2 weeks after fledging. (Holt and Leasure, 1993; Sparks and Soper, 1989; Pearson, 1936; Welty, 1975)

Breeding interval: Short-eared owls typically breed once yearly in the spring. Second broods have been reported but data is still needed to confirm this.

Breeding season: Short-eared owls typically breed late March to June, but mostly in April. In the southern hemisphere, breeding begins in September.

Range eggs per season: 1 to 11.

Average eggs per season: 5.6.

Range time to hatching: 21 to 37 days.

Range fledging age: 24 to 36 days.

Range time to independence: 31 to 43 minutes.

Average age at sexual or reproductive maturity (female): 1 years.

Average age at sexual or reproductive maturity (male): 1 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous

Average eggs per season: 6.

Average age at sexual or reproductive maturity (male)
Sex: male: 365 days.

Average age at sexual or reproductive maturity (female)
Sex: female: 365 days.

Only females brood and feed nestlings, while male provide food and defend the nest with distraction displays and vocalizations. Females protect nestlings from some weather conditions by brooding when young, and mantling when larger. When they are born young are semi-altricial, which means that they are relatively immobile and helpless when they hatch, but are down-covered rather than naked. (Holt and Leasure, 1993)

Parental Investment: altricial ; male parental care ; female parental care

A skilled hunter, the short-eared owl is most active during the morning, late afternoon and night, when it can be seen flying low above the ground searching for prey (2) (4). The structure of the wings and feathers give this species impressive aerial agility, and make its flight almost entirely silent. This is a very useful adaptation, as this species mainly hunts by sound, and also means that prey are not alerted to its presence. The short-eared owl feeds upon small mammals up to the size of hares, but will also take birds. Feeding is a rather gruesome affair, and involves the owl decapitating its prey, before pulling out the entrails, or, in the case of birds, pulling off the wings and swallowing them whole (2). In order to attract a mate, the male short-eared owl carries out a dramatic aerial display, involving rising quickly, hovering and descending with exaggerated wing beats, along with singing and wing-clapping (2) (4). Breeding pairs generally remain together for a single breeding season, although it is possible that breeding with multiple partners may also occur. Egg-laying takes place between March and June in the northern hemisphere, while in the southern hemisphere it commences in September. The female constructs a nest comprising a scraped out bowl in the ground lined with grasses and downy feathers. A clutch of between 5 and 10 eggs is laid and incubated by the female for 26 to 29 days, while the male brings food and defends the nest. At 12 to 18 days after hatching the young leave the nest, but are unable to fly and so hide in vegetation. This behaviour serves to minimise time spent in the nest, where predation is most likely to occur. The short-eared owl reaches sexual maturity at 1 year or less and may live for around 13 years (2). Although in the southern parts of its range the short-eared owl generally remains in the same location throughout the year, northern populations are highly migratory and make long-distance journeys to find food. Interestingly, if this species finds a wintering area with an abundant food supply it may remain there permanently (2).

Several state offices of the United States bird conservation organisation Audubon have initiated grassland protection and restoration initiatives, which should help to counteract the decline that this species is experiencing in some parts of its range (5).

The short-eared owl's scientific name flammeus, meaning “fiery”, is a reference to its boldly streaked plumage, which provides excellent camouflage when concealed amongst vegetation (4). This species has a large round head, with a white-bordered facial disc, and striking yellow eyes framed with black. The plumage is mostly mottled brown and buff on the upperparts, with black bars on the wings and tail feathers, while the breast is whitish or pale buff, with dense vertical streaking. The underwing is buffish-white, with a black tip, and a distinctive ochre patch just beyond the mid-wing, on the leading edge. The female short-eared owl is slightly larger than the male, with heavier streaking and browner upperparts, while the juvenile is darker still, with a brownish-black facial disc. There are ten recognised subspecies of short-eared owl, which vary in terms of location and colouration. Perhaps the most distinctive of these subspecies is Asio flammeus galapagoensis, which has extremely dark plumage and larger black regions around the eyes (2).

The short-eared owl is mostly found in open country, occupying tundra, marshland, grassland, savanna, sand dunes and moorland from sea level to elevations as high as 4,000 metres in the Andes (2). It requires sufficient vegetation to provide cover for nesting, as well as an abundance of small mammal prey (2) (4).

One of the most widespread owl species, the short-eared owl's range extends throughout the Americas, Europe and Asia (5). Subspecies Asio flammeus flammeus has the widest distribution and is known to breed in Iceland, the British Isles and much of Europe and Asia, as far east as the Kamchatka Peninsula and the Commander Islands, and south as far as Spain and north-east China. This subspecies is also found in North America from western and northern Alaska, east through Canada and south to central USA. The other subspecies have smaller ranges: Asio flammeus ponapensis occurs on Pohnpei Island in the East Caroline Island Group; Asio flammeus sandwichenis inhabits several Hawaiian Islands; Asio flammeus domingensis occupiesHispaniola and Cuba; Asio flammeus portoricensis is found on Puerto Rico; Asio flammeus pallidicaudus inhabitsnorthern Venezuela and Guyana; Asio flammeus bogotensis occurs in Colombia, Ecuador and north-west Peru; Asio flammeus galapagoensis is only found on theGalapagos Islands; Asio flammeus suinda inhabits southern Peru, western-central Bolivia, Paraguay, south-east Brazil, south to Tierra del Fuego; and Asio flammeus sanfordi is restricted to the Falkland Islands (2).

Classified as Least Concern (LC) on the IUCN Red List (1) and listed on Appendix II of CITES (3).

With its expansive range, and accordingly large population, on a global scale the short-eared owl is far from threatened (1) (2). Nevertheless, in many parts central Europe, Russia and the USA, this species is in decline, and is considered to be the rarest and most threatened owl in north-east USA. Some of the main reasons for this appear to be intensification of agriculture, urban expansion and the use of rodent poisons and other pesticides (2).

Casual breeder, regular passage visitor and winter visitor.

The small tufts of feathers on its forehead give the Short-eared Owl its name. Like all birds, however, the Short-eared Owl’s real ears are small openings hidden underneath the feathers on the sides of its head. This species possesses the short legs, rounded wings, large yellow eyes, and disk-shaped face characteristic of owls. The Short-eared Owl may also be identified by its size (15 inches), streaked brown-and-tan body, and off-white face. Males and females are similar at all seasons. The Short-eared Owl occurs across much of the world, being absent only from polar regions, isolated oceanic islands, and Australia. In North America, the Short-eared Owl breeds across Canada, Alaska, and the northern tier of the United States. Populations breeding in colder regions migrate south for the winter, while warmer parts of the Short-eared Owl’s breeding range host this species all year. In winter, Short-eared Owls may be found across much of the United States and south to central Mexico. Short-eared Owls breed primarily in open, treeless habitats such as tundra, grassland, and prairie. This species also frequents open habitats in winter, when it may be found in fields and marshes. Typical for an owl, the Short-eared Owl eats small mammals, such as mice, voles, and shrews, and may be found in greater numbers where prey is plentiful. The Short-eared Owl is an adept night hunter, using its excellent hearing to locate prey on the ground in order to fly down and capture it with its talons. However, like some other owls, this species frequently hunts during the day as well. This fact, combined with the Short-eared Owl’s preference for open habitat, makes this a comparatively easy owl species to observe.

Threat Status: Least Concern

Unlike most owls, you see short-eared owls flying also during the day. Their flame-colored plumage is easy to recognize in daylight. It's no coincidence that their Latin name describes this feature (flammeus). Short-eared owls are the only species of owls in the Netherlands that build their own nest. It's no more than a hollow, lined with grass and hidden in the vegetation. During years with lots of voles, these owls will lay as many as a dozen eggs. They protect their nests from predators using the cripple-wing technique: pretend to make an easy prey by walking around with a 'wounded' wing, thusly fooling the intruder and taking its attention away from the nest.

The small tufts of feathers on its forehead give the Short-eared Owl its name. Like all birds, however, the Short-eared Owl’s real ears are small openings hidden underneath the feathers on the sides of its head. This species possesses the short legs, rounded wings, large yellow eyes, and disk-shaped face characteristic of owls. The Short-eared Owl may also be identified by its size (15 inches), streaked brown-and-tan body, and off-white face. Males and females are similar at all seasons. The Short-eared Owl occurs across much of the world, being absent only from polar regions, isolated oceanic islands, and Australia. In North America, the Short-eared Owl breeds across Canada, Alaska, and the northern tier of the United States. Populations breeding in colder regions migrate south for the winter, while warmer parts of the Short-eared Owl’s breeding range host this species all year. In winter, Short-eared Owls may be found across much of the United States and south to central Mexico. Short-eared Owls breed primarily in open, treeless habitats such as tundra, grassland, and prairie. This species also frequents open habitats in winter, when it may be found in fields and marshes. Typical for an owl, the Short-eared Owl eats small mammals, such as mice, voles, and shrews, and may be found in greater numbers where prey is plentiful. The Short-eared Owl is an adept night hunter, using its excellent hearing to locate prey on the ground in order to fly down and capture it with its talons. However, like some other owls, this species frequently hunts during the day as well. This fact, combined with the Short-eared Owl’s preference for open habitat, makes this a comparatively easy owl species to observe.

More info for the terms: forest, taiga, tundra

The short-eared owl occurs in most open plant communities in North
America [12,13,21,22,28]. Taiga is usually used only in late summer
[12]. The owl avoids tundra and closed-canopy brushland and forest
[12,21,22,32].

short-eared owl

Information on state- and province-level protection status of animals in the
United States and Canada is available at NatureServe, although recent
changes in status may not be included.

More info for the term: cover

Nesting cover - Short-eared owl require open areas with dense, tall
herbs for nesting. They are the only North American owl that habitually
build their own nest each year. Nesting short-eared owl build the nest
with sticks and rotting vegetation; they approach it through a short
tunnel in the thick grass [28]. Duebbert and Lokemoen [15] found that
in North Dakota rangeland planted to smooth brome (Bromus inermis),
intermediate wheatgrass (Thinopyrum intermedium), and tall wheatgrass
(Elytrigia elongata), owls selected sites where grass cover was 12 to 24
inches (30-60 cm) tall. Seventy-five percent of nests were
three-fourths concealed from the sides; tops were mostly open. Evrard
and others [18] found that in a Wisconsin old field, nesting cover was
mostly 3-foot (90-cm) quackgrass (Elytrigia repens).

Hunting cover - Short-eared owl require open landscapes for hunting.
They generally hunt on the wing, flying low [28], but occasionally hunt
from low perches such as saplings and fenceposts [7].

Roosting cover - Short-eared owl usually roost on the ground or on grass
tussocks, although they occasionally use low brush [28], fenceposts, and
telephone poles [9]. During winter in snow country, they often roost
communally in low-growing conifers [12,28,33,39]. Observers in New
Jersey saw short-eared owl flocking together and roosting in short
conifers whenever snow cover was greater than 30 inches (75 cm) [9].

The short-eared owl occurs on all continents except Australia and
Antarctica [5,12,28]. In North America, it is distributed from Alaska
and all Canadian provinces except the Northwest Territories south
through the conterminous United States to central Mexico. It also
occurs on Pacific and Caribbean islands including Hawaii, Puerto Rico,
and the Virgin Islands [12,22,23,28].

Unlike most owls, short-eared owl hunt both day and at night until
sufficient prey are taken [12,28]. Throughout most of North America,
the meadow vole (Microtus pennsylvanicus) is selectively hunted and
comprises at least 90 percent of the short-eared owl's diet
[5,12,14,26,28]. Clark [12] speculated that on this continent,
short-eared owl cannot reproduce unless sufficient meadow vole are
taken. Current knowledge of short-eared owl food habits and nutritional
requirements is insufficient to determine whether this is true, however
[50]. Minor items in the short-eared owl diet include other voles
(Microtus spp.), deer mouse (Peromyscus maniculatus), shrews
(Soricidae), and small birds [9,46,48]. In Hawaii, the house mouse (Mus
musculus) and the Polynesian rat (Rattus exulans) are primary prey
[22,42].

More info for the terms: fire suppression, succession

Fire was historically an important disturbance in many of the plant
communities short-eared owl occupy. It created grass patches within
shrublands, maintained the open structure of parklands, and prevented
woody plant invasion of marshlands and grasslands. Although much of
short-eared owl decline can be attributed to urbanization, at least some
is probably due to succession of open plant communities to closed ones
as a result of fire suppression. Expansion of eastern deciduous species
into prairie, for example, has reduced short-eared owl habitat [32].

More info on this topic.

This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

13 Black spruce - tamarack
37 Northern white-cedar
38 Tamarack
68 Mesquite
209 Bristlecone pine
242 Mesquite
250 Blue oak - Digger pine

More info on this topic.

This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

More info for the term: shrub

FRES26 Lodgepole pine
FRES28 Western hardwoods
FRES29 Sagebrush
FRES30 Desert shrub
FRES32 Texas savanna
FRES33 Southwestern shrubsteppe
FRES34 Chaparral-mountain shrub
FRES36 Mountain grasslands
FRES37 Mountain meadows
FRES38 Plains grasslands
FRES39 Prairie
FRES40 Desert grasslands
FRES41 Wet grasslands
FRES42 Annual grasslands
FRES44 Alpine

More info on this topic.

This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the terms: cactus, forest, shrub

K022 Great Basin pine forest
K030 California oakwoods
K042 Creosotebush - bursage
K043 Paloverde - cactus shrub
K048 California steppe
K049 Tule marshes
K051 Wheatgrass - bluegrass
K052 Alpine meadows and barren
K053 Grama - galleta steppe
K054 Grama - tobosa prairie
K055 Sagebrush steppe
K056 Wheatgrass - needlegrass shrubsteppe
K057 Galleta - three-awn shrubsteppe
K058 Grama - tobosa shrubsteppe
K061 Mesquite - acacia savanna
K063 Foothills prairie
K064 Grama - needlegrass - wheatgrass
K065 Grama - buffalograss
K066 Wheatgrass - needlegrass
K073 Northern cordgrass prairie
K074 Bluestem prairie
K077 Bluestem - sacahuista prairie
K079 Palmetto prairie
K080 Marl - everglades
K088 Fayette prairie
K092 Everglades
K093 Great Lakes spruce - fir forest
K094 Conifer bog

More info for the term: cover

Short-eared owl populations have declined over most of their former
North American range due to habitat loss [24]. By 1986, they were
widely reported as declining in the Hudson-Delaware region, the Midwest,
and the Southern Great Plains; in severe decline in central-southern,
prairie, and mid-Pacific coast regions; and long since extirpated from
southern California [17]. In the Midwest, short-eared owl are currently
reported only from remnant prairie [44]. Baldner [2] and Sinclair [43]
attributed the species' rarity in Iowa to loss of tallgrass prairie.
Urbanization of coastlands has decimated populations in Massachusetts
[12,45]. Central California populations have been reduced by
agricultural and urban development [21]. Marti and Marks [35] have
listed populations as stable in Oregon and Colorado and fluctuating but
stable in Montana.

Short-eared owl often persist near farmland borders where agriculture is
not intensive. Intensive agriculture or conversion of meadows,
wetlands, or other short-eared owl habitat to cropland, however, results
in short-eared owl decline [24,29].

Overgrazing removes cover needed for nesting and brooding [21,35]. In
Idaho, short-eared owl were present in ungrazed big sagebrush-standard
wheatgrass (Artemisia tridentata-Agropyron desertorum), but not in areas
grazed by sheep [40,41].

AL
AK
AZ
AR
CA
CO
CT
DE
FL
GA

HI
ID
IL
IN
IA
KS
KY
LA
ME
MD

MA
MI
MN
MS
MO
MT
NE
NV
NH
NJ

NM
NY
NC
ND
OH
OK
OR
PA
RI
SC

SD
TN
TX
UT
VT
VA
WA
WV
WI
WY

DC
PR
VI


AB
BC
MB
NB
NF
NS
ON
PE
PQ

SK
YT

MEXICO

Large avian predators such as great horned owl (Bubo virginianus) [4],
snowy owl (Nyctea scandiaca) [33], and rough-legged hawk (Buteo lagopus)
[36] occasionally prey upon both juvenile and adult short-eared owl.
Ground-nest predators such as American badger (Taxidea taxus) [47] and
gulls (Larus spp.) [12] eat the eggs.

More info for the terms: cover, heath, herbaceous, marsh, taiga, tundra

Short-eared owl occupy a variety of open habitats within their wide
geographical distribution. Preferred habitats include fresh- and
saltwater marshes [6,7,12,21], coastal plains [24], tamarack (Larix
laricina)-black spruce (Picea mariana) bogs [8], old fields [14,18],
prairies [30], sagebrush (Artemisia spp.) steppes [38,40,42], wet
meadows, grasslands, open shrublands, and montane parklands [21,22].

Since the species is only weakly migratory, nesting, hunting, and
wintering habitats are generally the same [12,28]. In Massachusetts,
short-eared owl in maritime heath occupied a home range of 63 to 198
acres (25-79 ha) [45]. In freshwater marsh, the home range was 184.8 to
303.5 acres (73.9-121.4 ha) [12].

Nesting habitat - Short-eared owl nest on dry ground in open areas with
dense herbaceous cover. Even in wetlands, dry microsites are selected
for nesting [13]. Taiga and tundra are poor nesting habitat [12].

Hunting habitat - The owl uses open ground where prey is available [7,33].

More info on this topic.

This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

1 Northern Pacific Border
2 Cascade Mountains
3 Southern Pacific Border
4 Sierra Mountains
5 Columbia Plateau
6 Upper Basin and Range
7 Lower Basin and Range
8 Northern Rocky Mountains
9 Middle Rocky Mountains
10 Wyoming Basin
11 Southern Rocky Mountains
12 Colorado Plateau
13 Rocky Mountain Piedmont
14 Great Plains
15 Black Hills Uplift
16 Upper Missouri Basin and Broken Lands

The currently accepted scientific name of short-eared owl is Asio
flammeus (Pontoppidan) [1]. It is in the family Strigidae [28]. Only
the type subspecies, Asio flammeus flammeus, occurs in North America.
A. f. ponapensis, Ponape short-eared owl, occurs on the Caroline
islands, and A. c. sandwichensis, Hawaiian short-eared owl, occurs on
the Hawaiian islands [13,28].

More info for the terms: heath, marsh, taiga

Age at sexual maturity - 1 year [27]

Courtship and breeding - Short-eared owl form pair bonds; whether the
pairing lasts past the breeding season is unknown [27]. Depending upon
latitude, courtship begins in mid-winter or early spring, and breeding
is completed by late winter or late spring. In Idaho and Massachusetts,
courtship begins in March and the female lays eggs by May [2,24]. In
Illinois, courtship begins in late April and egg-laying is complete by
early May [28].

Nesting and incubation - Most North American populations are
single-brooded, although short-eared owls in the South are sometimes
double-brooded. Clutch size varies from 2 to 14 eggs, with 5 to 7 eggs
being the norm [28]. The female tends to lay more eggs when prey
populations are high [13]. Murray [37] found that clutch sizes were
significantly larger with increasing latitude; he attributed this to
larger rodent populations in the North. The female lays her eggs
asynchronously, from 2 to 7 days apart. Regional egg-laying dates are
given below [28].

Alaska and arctic Canada: June 5-July 2; usually June 10-June 25
southern Canada: April 30-June 22; usually May 4-June 17
northern United States: April 14-June 15; usually April 23-June 10
Midwest: April 4-June 8; usually April 16-May 25
southern California: March 20-May 18; usually March 26-April 26

Destroyed clutches are usually replaced within 2 weeks; second clutch
sizes are smaller [12,28].

The female is the sole incubator; the male supplies her with food during
incubation. Incubation time is 21 to 29 days per egg. The eggs hatch
asynchronously, about one every 3 days. The brood therefore consists of
different-aged sibs. The female does all brooding; the male hunts to
feed the young and his mate [12,16,24,28].

Fledging - Young leave the nest on foot about 16 days after hatching and
fledge at approximately 29 days of age [24,25]. The brood is dependent
on the parents for food "for a period of time" after fledging [13].
After all young have fledged, parents lead the brood to a new area if
prey is scarce on the nesting grounds [34].

Clark [12] reported a mean clutch size of 8.6 for short-eared owl nests
in a Massachusetts freshwater marsh. An average of 7.0 young per nest
hatched, and an average of 4.0 young per nest fledged. On Nantucket
maritime heath, Tate and others [45] found a mean clutch size of 5.7 in
1985. An average of 3.4 eggs hatched, and 2.0 young per nest fledged. In
1986, mean clutch size was 7.7, with an average of 7.0 eggs hatching and
3.4 young per nest fledging.

Migration - Much remains to be discovered about short-eared owl
migration dates and routes. The short-eared owl is well adapted to heat
and cold. As a result, it is apparently only weakly migratory [28].
Short-eared owl populations at the edge of the species' northern
distribution move south in late summer or early fall, but it is unclear
whether more southerly populations migrate or remain in an area as
permanent residents. Banding records are few, but limited studies show
that some individuals in populations south of taiga are regular
migrants. Others are irregular migrants, leaving in some years but not
others. Some owls probably migrate to new areas as young adults, then
become permanent residents. Migration routes are generally north-south,
but not always. Some migrants, for example, move back and forth from
North Dakota and eastern Oregon [12].

Except for populations at climatic extremes, when entire populations
migrate it is usually in response to depletion of the prey base rather
than seasonal climate changes. Short-eared owl rapidly move out of an
area bereft of prey, and rapidly move into areas where rodent
populations are rising [12,29,34].

Longevity - Captive birds have lived to age 15. It is unknown how long
short-eared owl usually survive in the wild [28].

More info for the terms: cover, fire regime

Fire can maintain or expand short-eared owl habitat. Burning after the
fledging stage, so that young owls are not lost to fire, is probably
best [30]. Because summer or fall fires are usually more severe than
spring fires, they would probably kill more woody vegetation, opening up
habitat as well as avoiding damage to reproduction. Burning during the
nesting season, however, does not totally eliminate reproduction of
ground-nesting birds such as short-eared owl. Kruse and Piehl [30]
recommended partial burning during the nesting season. Partial burns
reduce cover less uniformly, but should result in higher recruitment of
ground-nesting birds than would complete burns conducted during the
nesting season.

FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find FIRE REGIMES".

In flight In Texel, North Holland, Netherlands

The short-eared owl (Asio flammeus) is a widespread grassland species in the family Strigidae. Owls belonging to genus Asio are known as the eared owls, as they have tufts of feathers resembling mammalian ears. These "ear" tufts may or may not be visible. The short-eared owl will display its tufts when in a defensive pose, although its very short tufts are usually not visible. The short-eared owl is found in open country and grasslands.