Index of Species Information
WILDLIFE SPECIES: Falco mexicanus
WILDLIFE SPECIES: Falco mexicanus
AUTHORSHIP AND CITATION :
Tesky, Julie L. 1994. Falco mexicanus. In: Fire Effects Information System, [Online].
U.S. Department of Agriculture, Forest Service,
Rocky Mountain Research Station, Fire Sciences Laboratory (Producer).
Available: http://www.fs.fed.us/database/feis/ .
COMMON NAMES :
The currently accepted scientific name for the prairie falcon is Falco
mexicanus Schlegel. It is in the family Falconidae . There are no
FEDERAL LEGAL STATUS :
See OTHER STATUS
OTHER STATUS :
Prairie falcon is under state monitor in Washington .
WILDLIFE DISTRIBUTION AND OCCURRENCE
WILDLIFE SPECIES: Falco mexicanus
GENERAL DISTRIBUTION :
Prairie falcons breed from central British Columbia, southern Alberta,
Saskatchewan, and North Dakota south to Baja California. They winter
from the northern parts of their breeding range south to central Mexico
and east to the Mississippi River [1,10,13,16].
FRES26 Lodgepole pine
FRES28 Western hardwoods
FRES30 Desert shrub
FRES32 Texas savanna
FRES33 Southwestern shrubsteppe
FRES34 Chaparral-mountain shrub
FRES36 Mountain grasslands
FRES37 Mountain meadows
FRES38 Plains grasslands
FRES40 Desert grasslands
FRES41 Wet grasslands
FRES42 Annual grasslands
BLM PHYSIOGRAPHIC REGIONS :
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
16 Upper Missouri Basin and Broken Lands
KUCHLER PLANT ASSOCIATIONS :
K008 Lodgepole pine - subalpine forest
K022 Great Basin pine forest
K023 Juniper - pinyon woodland
K024 Juniper steppe woodland
K026 Oregon oakwoods
K027 Mesquite bosque
K030 California oakwoods
K031 Oak - juniper woodlands
K032 Transition between K031 and K037
K034 Montane chaparral
K035 Coastal sagebrush
K037 Mountain-mahogany - oak scrub
K038 Great Basin sagebrush
K040 Saltbush - greasewood
K042 Creosotebush - bursage
K043 Paloverde - cactus shrub
K044 Creosotebush - tarbush
K045 Ceniza shrub
K047 Fescue - oatgrass
K048 California steppe
K050 Fescue - wheatgrass
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
K059 Trans-Pecos shrub savanna
K060 Mesquite savanna
K061 Mesquite - acacia savanna
K062 Mesquite - live oak savanna
K063 Foothills prairie
K064 Grama - needlegrass - wheatgrass
K065 Grama - buffalograss
K066 Wheatgrass - needlegrass
K067 Wheatgrass - bluestem - needlegrass
K068 Wheatgrass - grama - buffalograss
K069 Bluestem - grama prairie
K070 Sandsage - bluestem prairie
K073 Northern cordgrass prairie
K074 Bluestem prairie
K075 Nebraska Sandhills prairie
K076 Blackland prairie
K077 Bluestem - sacahuista prairie
K083 Cedar glades
K085 Mesquite - buffalograss
K086 Juniper - oak savanna
K087 Mesquite - oak savanna
K088 Fayette prairie
SAF COVER TYPES :
66 Ashe juniper - redberry (Pinchot) juniper
67 Mohrs (shin) oak
218 Lodgepole pine
220 Rocky Mountain juniper
222 Black cottonwood - willow
233 Oregon white oak
235 Cottonwood - willow
238 Western juniper
239 Pinyon - juniper
240 Arizona cypress
241 Western live oak
243 Sierra Nevada mixed conifer
246 California black oak
249 Canyon live oak
250 Blue oak - Digger pine
255 California coast live oak
SRM (RANGELAND) COVER TYPES :
PLANT COMMUNITIES :
Prairie falcons commonly occur in arid and semiarid shrubland and
grassland community types. They are also occasionally found in open
parklands within coniferous forests . In the Sierra Nevada prairie
falcons are primarily associated with perennial grasslands, lodgepole
pine (Pinus contorta) of varying canopy closures, and alpine meadows
. In British Columbia prairie falcons inhabit open treeless areas
including arid grasslands and sagebrush (Artemisia spp.) steppe, alpine
meadows and ridges, and less frequently, marshes and farmlands . In
northeastern Wyoming prairie falcons prefer grassland habitats over
those with sagebrush when given the choice . Prairie falcon habitat
in northern Mexico is a combination of forest, woodland, and chaparral
in the mountainous terrain surrounding the nest site, and grassland and
desert scrub on the open slopes and valleys used for foraging .
BIOLOGICAL DATA AND HABITAT REQUIREMENTS
WILDLIFE SPECIES: Falco mexicanus
TIMING OF MAJOR LIFE HISTORY EVENTS :
Age at sexual maturity - Some prairie falcons breed when 1 year old, but
most probably do not begin breeding until 2 years old [16,27].
Breeding season - The breeding season varies depending on geographic
area. Reproductive activity usually begins in late winter or early
spring. Courtship and mate selection occur on the breeding grounds at
least 1 month before egg laying . In California prairie falcons
breed from mid-February to mid-September, with peak activity from early
May to early August . In Nevada they arrive on the breeding grounds
in March and lay eggs in March or early April .
Clutch size and incubation - Prairie falcons generally lay three to six
eggs. The eggs are incubated for 29 to 33 days. If the first clutch is
destroyed another may be laid after 20 to 25 days [27,32].
Fledging - Nestlings fledge in 40 days .
Migration - Other than local movements to low elevations, many adult
prairie falcons tend to be residents on their breeding range if there is
an adequate year-round food supply [27,32]. During the nonbreeding
season most juveniles and some adult prairie falcons migrate to the
intermontane valleys and Great Plains . Young prairie falcons in
Wyoming and Colorado often move eastward from mountainous areas to the
plains, where horned larks (Eremophila alpsetris) are numerous .
The adults seem to establish winter territories on their winter range
. In north-central Utah migrant prairie falcons usually arrive in
the valleys in late October and remain there until March .
Longevity - Prairie falcons may live as long as 20 years; the longest
known banding recovery is 13 years. Immature mortality has been
estimated to be 75 percent and average annual adult mortality 25
percent. The average life expectancy of the prairie falcon has been
estimated at 2.4 years .
PREFERRED HABITAT :
Prairie falcons occupy open treeless terrain including prairies,
deserts, riverine escarpments, canyons, foothills, and mountains in
relatively arid western regions [13,16,32,34]. In the Sierra Nevada
prairie falcons range above timberline in late summer but winter at
lower elevations .
Nesting habitat - During the breeding season prairie falcons are
commonly found in foothills and mountains which provide cliffs and
escarpments suitable for nest sites . Occasionally prairie falcons
nest at altitudes of 10,000 feet (3,048 m), although this is
exceptional. The highest recorded nest site is 11,699 feet (3,566 m) in
Colorado . Prairie falcons generally nest on cliffs, from low rock
outcrops of 30 feet (9 m) to vertical cliffs 400 feet (121 m) high.
They prefer cliffs with a sheltered ledge with loose debris or gravel
for a nest, overlooking treeless country for hunting. They may also
nest in potholes or large caves . Prairie falcons sometimes use old
nests of ravens (Corvus spp.), hawks, and golden eagles (Aquila
chrysaetos) [8,13,32]. Nest sites with southern or eastern exposures
are preferred. However, in southwestern Idaho no preference was noted
, and in the San Joaquin Valley, California, most prairie falcon
nests had northern exposures and no south-facing ledges were used .
Prairie falcons usually have alternate nesting sites located on the same
cliff and tend to use alternate ledges in succeeding years. Nesting
failure does not seem to deter use of the cliff in the following year
Of 36 nesting cliffs in Colorado and Wyoming, 14 were sandstone, 10 were
sedimentary conglomerate, 7 were limestone, and 5 were granite.
Twenty-two nesting ledges faced south, five faced north and nine faced
east or west . In southeastern Montana and northern Wyoming,
Phillips and others  reported that all prairie falcon nests were
found in cracks or potholes in sandstone cliffs. The mean distance
between occupied nest sites was 4.8 miles (7.8 km) .
In British Columbia prairie falcon nests were situated on ledges, in
caves, in crevices, and in potholes on cliffs. Nesting cliffs were
granite or sandstone and ranged from 49 to 453 feet (15-138 m) in
height; the actual nest site ranged from 29 to 295 feet (9-90 m) from
the base of the cliff .
Foraging habitat - Prairie falcons generally forage in open areas with
low vegetation containing ground squirrels (Spermophilus spp.) and
passerine birds. They tend to have definite hunting ranges. When food
is plentiful these areas are confined to the least possible radius
necessary to secure required food supplies , but prairie falcons
will forage up to 15 miles (24 km) from the nest . The usual
hunting method consists of flying at a altitude of 50 to 300 feet (15-91
m) and diving at potential prey. Prairie falcons also hunt from
perches. Prairie falcons often eat while perched on a convenient
vantage point or on the ground where they have captured their prey .
During the breeding season extra food is cached near the nest for
subsequent use .
Winter habitat - Winter habitat for prairie falcons is generally the
same as nesting habitat, except that high elevation areas are not used
. In northern Colorado winter ranges (maximum distance between
observation points of individual marked birds) averaged 3.8 miles (6.1
km) for males and 7.2 miles (11.5 km) for females. The maximum range
was 12.1 miles (919.4 km) for one female .
COVER REQUIREMENTS :
Nests are often recessed in a cliff to provide protection from mammalian
predators, shelter, and shade [1,12,27]. Nests are rarely located at
the top of a cliff . In southwestern Idaho 60 percent of the nests
surveyed were in cavities that afforded some protection for the eggs and
young; 19 percent were on exposed ledges . The need for cover does
not seem to affect foraging behavior. Prairie falcons prefer to hunt in
open areas covered only by short, sparse ground vegetation .
FOOD HABITS :
Prairie falcons eat a wide variety of prey including mammals, birds,
reptiles, and insects. In many areas mammals, primarily ground
squirrels, are the major prey item eaten during the breeding season
[16,19,32]. In areas lacking ground squirrels, small- to medium-sized
birds and reptiles are major prey items . The horned lark is the
main food item for prairie falcons wintering in the wheat-growing areas
of the western United States [16,32].
Prairie falcons develop prey preferences and will concentrate on a
single species or group of species exclusively for as long as possible.
When those species have diminished in the hunting area, a new prey
species is selected and hunted .
Some prairie falcon prey items not mentioned above include pocket
gophers (Geomyidae), cottontails and jackrabbits (Leporidae), pikas
(Ochotona spp.), wood rats (Neotoma spp.), mice, mourning doves (Zenaida
macroura), burrowing owls (Athene cunicularia), jays (Corvidae), western
meadowlarks (Sturnella neglecta), blackbirds, shrikes (Lanius spp.),
wrens (Troglodytidae), lark buntings (Calamospiza melanocorys), magpies
(Pica spp.), sparrows (Emberizidae), quail (Phasianidae), longspurs
(Calcarius spp.), pigeons (Columbidae), ducks (Anatidae), lizards,
grasshoppers, and beetles [13,27,32].
Adult prairie falcons are seldom killed by predators, although adult
incubating birds are sometimes taken by great horned owls (Bubo
virginianus) at night . Predation by coyotes (Canis latrans), dogs
(Canis familiaris), badgers (Taxidea taxus), bobcats (Lynx rufus),
golden eagles, and great horned owls is probably the greatest overall
factor in nestling mortality by predators [16,26,32].
MANAGEMENT CONSIDERATIONS :
The current breeding status of prairie falcons is unknown. In Utah
prairie falcons show reduced occupation rates at historical nests and
total extirpation from others. Some western Montana populations may not
be stable, while Idaho contains an apparently stable population. A
declining Canadian population has shown some recovery .
Breeding habitat loss is probably the most important factor threatening
prairie falcon populations. Artificial aeries with reinforcing frames
should be considered for prairie falcon management where development
activities affect the availability or useability of natural aeries or
where substrate conditions reduce aerie longevity [25,31].
Alteration of prey habitat has also had an impact on prairie falcon
populations . Broad expanses of grassland and prairie with
occasional scattered trees provide excellent habitat for prairie
falcons. Unfortunately much of this habitat has been altered by
cultivation, water impoundments, or heavy grazing, which reduces the area
of suitable habitat for many prey species . Range management
practices that produce or maintain ranges in good condition provide a
greater abundance and variety of prey for many raptor species including
prairie falcons .
Organochlorine contaminants and mercury appear to have been primarily
responsible for earlier prairie falcon declines because of direct
effects on prairie falcons and effects on their prey base. Restrictions
on DDT and mercury use have considerably alleviated the declines caused
by biocide pollution, but populations in areas of agricultural pesticide
use continue to show lowered reproduction. In areas where prairie
falcons feed primarily on birds, productivity and nest success are much
lower than where the diet is primarily mammalian. In California pest
control eliminated 1 million passerines from 1966 to 1972; roughly 30
percent of these were horned larks .
Human disturbance near prairie falcon nest sites during the breeding
season may result in nest abandonment . Construction of homes at
the base of cliffs throughout the West has caused prairie falcons to
leave areas where they may have nested for generations . High
levels of human disturbance near historical nesting territories were
thought to be responsible for declines of prairie falcons in the Mojave
Desert . Boyce  suggested placing roads at least a 15-minute walk
from a prairie falcon nest, preferably a 30-minute walk. He also
suggests placing restrictions on recreational activities and/or closure
of habitat near nests if possible.
Prairie falcons are being bred successfully in captivity.
Captive-raised birds are being placed in wild aeries to help managers
develop techniques for reintroduction of peregrine falcons.
Captive-raised prairie falcons are also raised for falconry purposes
FIRE EFFECTS AND USE
WILDLIFE SPECIES: Falco mexicanus
DIRECT FIRE EFFECTS ON ANIMALS :
Direct mortality from fire is rare for raptors . Adults can
probably easily escape fire, and eggs and nestlings are rarely in
locations that can burn.
HABITAT RELATED FIRE EFFECTS :
Prairie falcons occur in the following five major fire-dependent plant
associations in the western United States: grasslands, semidesert
shrub-grasslands, sagebrush-grasslands, chaparral, and pinyon-juniper
(Pinus spp.-Juniperus spp.) .
Grassland raptors such as prairie falcons have been adversely affected
by fire exclusion wherever woodlands have encroached upon grasslands
. Periodic fire may enhance the foraging habitat of prairie falcons
and increase the prey base [3,14,24]. Several studies indicate that
many small mammal and bird populations increase rapidly subsequent to
burning in response to increased food availability [14,24].
Additionally, fires in grasslands may increase prey availability by
removing accumulated litter and reducing cover . Fire suppression in
grasslands is detrimental to populations of small bird and mammal
herbivores due to organic matter accumulation and reduced plant vigor
Raptors associated with pinyon-juniper woodlands depend upon edges of
openings created by fire and scattered islands of unburned woodlands
Although fire is often beneficial to prairie falcon prey species, Yensen
and others  reported that in the Snake River Birds of Prey Area,
southwestern Idaho, fire may reduce populations of Townsend's ground
squirrels (Spermophilus townsendii), a major prey species of prairie
FIRE USE :
To create or maintain desert grasslands, prescribed burning at an
interval not less than 5 years is recommended. Periodic fire at
approximately 5-year intervals will probably maintain an open condition,
though burning over successive years may be necessary to eliminate woody
invaders. Five-year intervals between fires allow for herbaceous plant
recovery while not adversely affecting prey populations. The goal of
prescribed burning in chaparral should be to create opportunities for
perennial grass to extend the open grass-shrub character. Complete
elimination of climax chaparral species is not recommended. Periodic
fire at approximately 5-year intervals will probably maintain an open
condition. In most cases, burning plans must be integrated with proper
range management. Postfire seeding of perennial grasses as well as rest
from livestock grazing may be necessary to achieve desired goals.
Because of human disturbance, prescribed burning should be deferred
until nesting is completed in areas where impact to breeding prairie
falcons may occur . For more information regarding the use of
prescribed fire in specific habitats for the benefit of raptors in
general, see Dodd .
WILDLIFE SPECIES: Falco mexicanus
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