Missouri Department of Conservation
Missouri Department of Conservation

Taxonomy

Common Name: SWAN, TRUMPETER

Phylum: CHORDATA

Class: AVES

Order: ANSERIFORMES

Family: ANATIDAE

Genus: CYGNUS

Species: BUCCINATOR

Taxonomic Authority: RICHARDSON

Taxonomy References: 014

Status

NONGAME
STATE RANK S1
GLOBAL RANK G4

Status References: 015 , 016 , 025 , 026

Habitat Summary

"Inhabit marshes, ponds, lakes and reservoirs with large areas of shallow (1-2.5 feet) water, extensive beds of emergent vegetation and stable water levels."

Primary Habitat: "Wetland matrix"

References: 004 , 007 , 008 , 009

Distribution

General Occurrence in State:

"Casual transient *23*. Migratory birds have been sighted at Thomas Hill wildlife area and Mingo National Wildlife Refuge since 1978 *01*."

County Occurance

County Occurence
Known Likely Unknown Not Likely Historic Extirpated
BOLLINGER ADAIR
RANDOLPH ANDREW
STODDARD ATCHISON
WAYNE AUDRAIN
BARRY
BARTON
BATES
BENTON
BOONE
BUCHANAN
BUTLER
CALDWELL
CALLAWAY
CAMDEN
CAPE GIRARDEAU
CARROLL
CARTER
CASS
CEDAR
CHARITON
CHRISTIAN
CLARK
CLAY
CLINTON
COLE
COOPER
CRAWFORD
DADE
DALLAS
DAVIESS
DEKALB
DENT
DOUGLAS
DUNKLIN
FRANKLIN
GASCONADE
GENTRY
GREENE
GRUNDY
HARRISON
HENRY
HICKORY
HOLT
HOWARD
HOWELL
IRON
JACKSON
JASPER
JEFFERSON
JOHNSON
KNOX
LACLEDE
LAFAYETTE
LAWRENCE
LEWIS
LINCOLN
LINN
LIVINGSTON
MACON
MADISON
MARIES
MARION
MCDONALD
MERCER
MILLER
MISSISSIPPI
MONITEAU
MONROE
MONTGOMERY
MORGAN
NEW MADRID
NEWTON
NODAWAY
OREGON
OSAGE
OZARK
PEMISCOT
PERRY
PETTIS
PHELPS
PIKE
PLATTE
POLK
PUTNAM
RALLS
RAY
REYNOLDS
RIPLEY
SALINE
SCHUYLER
SCOTLAND
SCOTT
SHANNON
SHELBY
ST. CHARLES
ST. CLAIR
ST. FRANCOIS
ST. LOUIS
STE. GENEVIEVE
STONE
SULLIVAN
TANEY
TEXAS
VERNON
WARREN
WASHINGTON
WEBSTER
WORTH
WRIGHT

References for distribution: 019 , 023 , 024 , 001

Distribution by Watersheds

South Fork from Headwaters to North Fork
Castor R. and Castor R. Diversion Channel
St. Francis R. from Headwaters to Wappapello Dam
St. Francis R. from Wappapello Dam to Arkansas Border
Little R.
Little Chariton R.
Black R.

Comments: "Likely to occur in units listed, based on county occurrence."

Distribution by Ecoregions

Central Till Plains, Mississippi River Alluvial Plains, Ozark Highlands

Comments: ""

Distribution by Potential Natural Vegetation

Bluestem Prairie/Oak Hickory Forest
Oak-Hickory Forest
Oak-Hickory-Pine Forest
Southern Floodplain Forest

Distribution by Natural Divisions of Missouri

Glaciated Plains: Grand River
Glaciated Plains: Eastern
Ozark Border: Mississippi River
Ozark: St. Francois Mountains
Ozark: Lower Ozark
Mississippi Lowlands: Crowley's Ridge
Mississippi Lowlands: Lowlands

Habitat Associations

Species is associated with "Terrestrial/Aquatic" habitats.

National Wetlands Inventory Association:

Lacustrine
Palustrine

Aquatic Associations:

"Lacustrine, littoral"
"Palustrine", "Emergent"

References for Aquatic Associations: 001 , 004 , 007 , 008

Habitat Types:

Pond, Lake, Reservoir
Marsh

References for Habitat Types: 001 , 004 , 007 , 008 , 017

Terrestrial Natural Communities:

Wetland
Marshes
Freshwater Marsh
Pond Marsh

References for Terrestrial Natural Communities: 001 , 004 , 007 , 008

Food Habits

Trophic Level:

"Omnivore"

Larval Food Habits

Comments for larval food habits:
""

References for larval food habits:

Juvenile Food Habits

Aquatic plants; Tubers
Aquatic plants; Rhizome
Aquatic plants; Bole/Stem
Aquatic plants; Leaves/Needles
Aquatic plants; Fruit/Seeds
Coleoptera (beetles); Not Specified
Algae; Not Specified
Cyperaceae (sedge); Not Specified
Najadaceae (pondweed); Not Specified
Alismaceae (water plantain, arrowhead); Not Specified
Spenopsida (horsetails); Not Specified
Haloragidaceae (water milfoil); Not Specified
Hydrocharitaceae (tape grass, water weed); Not Specified
Crustaceans; Not Specified
Insects Insects; Not Specified

Comments for Juvenile Food Habits:
""

References Juvenile Food Habits 021 , 004 , 005 , 007 , 008

Adult Food Habits

Aquatic plants; Tubers
Najadaceae (pondweed); Tubers
Aquatic plants; Rhizome
Aquatic plants; Bole/Stem
Haloragidaceae (water milfoil); Bole/Stem
Cyperaceae (sedge); Leaves/Needles
Aquatic plants; Leaves/Needles
Najadaceae (pondweed); Leaves/Needles
Haloragidaceae (water milfoil); Leaves/Needles
Cyperaceae (sedge); Fruit/Seeds
Magnoliaceae (magnolia); Fruit/Seeds
Nymphaeaceae (lily); Fruit/Seeds
Cyperaceae (sedge); Not Specified
Lemnaceae (duckweed); Not Specified
Alismaceae (water plantain, arrowhead); Not Specified
See comments on seasonal variation; Not Specified
Spenopsida (horsetails); Not Specified
Dicotyledoneae (dicots); Not Specified
Cruciferae (mustard); Not Specified
Haloragidaceae (water milfoil); Not Specified
Hydrocharitaceae (tape grass, water weed); Not Specified
Gramineae (grass); Not Specified

Comments for Adult Food Habits:
""

References Adult Food Habits 010 , 021 , 022 , 007 , 008 , 009

Niche Requirements

Egg Niche Requirements

References for egg niches requirements:

Feeding Larvae Niche Requirements

References for feeding larvae niche requirements:

Resting Larvae Niche Requirements

References for resting Larvae niche requirements:

Feeding Juvenile Niche Requirements

Current velocity: no noticable current
Water level specified in comments(00180)
Water depth: shallow
Water depth specified in comments(00230)
Inland wetlands: marsh
Isolation from humans required; should be relatively inaccessible

References for feeding juvenile niche requirements: 020 , 005 , 007 , 008

Resting Juvenile Niche Requirements

Other niche requirements specified in comments(99999)
Water level specified in comments(00180)
Water depth specified in comments(00230)

References for resting juvenile niche requirements: 020 , 005 , 007 , 008

Breeding Adult Niche Requirements

Other niche requirements specified in comments(99999)
Aquatic vegetation specified in comments(00120)
Density of aquatic vegetation specified in comments(00130)
Current velocity: no noticable current
Water level specified in comments(00180)
Water depth: shallow
Water depth specified in comments(00230)
Inland wetlands: marsh
Isolation from humans required; should be relatively inaccessible

References for feeding Adult niche requirements: 020 , 004 , 005 , 007 , 008 , 009

Feeding Adult Niche Requirements

Density of aquatic vegetation specified in comments(00130)
Current velocity: no noticable current
Water level specified in comments(00180)
Water depth: shallow
Water depth specified in comments(00230)
Inland wetlands: marsh
Inland wetlands: pond, lake, reservoir

References for feeding adult niche requirements: 005 , 007 , 008

Resting Adult Niche Requirements

Density of aquatic vegetation specified in comments(00130)
Current velocity: no noticable current
Water level specified in comments(00180)
Water depth: shallow
Water depth specified in comments(00230)
Inland wetlands: marsh
Inland wetlands: pond, lake, reservoir

References for resting adult niche requirements: 005 , 008

Niche Requirement Summary

Aquatic vegetation specified in comments(00120)
Current velocity: no noticable current
Density of aquatic vegetation specified in comments(00130)
Inland wetlands: marsh
Inland wetlands: pond, lake, reservoir
Isolation from humans required; should be relatively inaccessible
Other niche requirements specified in comments(99999)
Water depth specified in comments(00230)
Water depth: shallow
Water level specified in comments(00180)

Comments about Life History:

Code Comment
015 Nest made of aquatic vegetation.*09,08*
007 In SD, captive swans began courtship display mid-January and continued until mid-March.*11*. Average date for initiation of egg-laying in NE and SD was mid April - mid May, average hatch date: mid May - mid June.*05*. At Copper River delta, data indicated nesting and incubation began as early as 3rd week-April and extended through 1st week in July.*08*
011 Muskrat houses often used as nest sites.*04,05,07*
013 May use same nest site for several years.*09,07,04,08*. 57/74 (77%) nests were located on or within a few feet of previously or subsequently used sites.*07*
026 Behavior characterized by defense of mating, nesting and feeding ground for young, defense of area other than concerned essentially with reproduction not known, interspecific aggressive behavior on nesting territory appears directed chiefly against larger birds.*07*. In AK, territorial maintenance continued from pair's arrival on nest site until well into brood season.*08*
031 Survival on grand prairie, alberta (fledging-1 year) was 42.9%. Majority of mortality apparently occurred during late winter or spring migration. Subadult survival (1 year-2 year) 70.9%.*13*. At Red Rock Lakes, hatching success varied 51-66%.*07*. On kenai, survival (hatching-flight stage) ranged 71-80% over 3 years, average hatching success 79%. At Copper River 55% hatching success.*08*
032 In alberta, it was calculated that each pair must reproduce for 3.8 years to replace pair unit, average life expectancy of adult birds = 5.2 years.*04*
034 In SD, predation became limiting factor in captive swans. Great horned owls, raccoons, bobcats and coyotes were important potential predators.*11*. Overall, seems to be 2 critical limiting factors: lack of breeding habitat and shortage of wintering habitat.*04,05,07,08*
016 Nest usually 6-12' in diameter, some mounds reached as much as 36" in height, mean height of 36 nests in AK = 18", nest cavity 10-16" diameter and 4-8" deep.*08,09*
017 Incubation 33-37 days at Red Rock Lakes refuge, kenai peninsula, and alberta canada.*07,08,04*, 33-35 days at Copper River delta.*08*. In MN, captive swans began hatching 30 days after last egg laid, hatching complete by day 32, cygnets left nest on morning of day 33. *12*
018 7-year mean clutch at Red Rock Lakes refuge 5.1 eggs.*07*. At Copper River, mean clutch 4.9, at kenai, mean clutch 5.3 eggs.*08*. Clutch 4-9 at LaCreek refuge, average 6.4 *05*
022 Successful nesting of at least 3 pairs of swans 33 months old in sd.*08*. Captive birds in SD begyran nesting at 2 years and 9 months.*11*. In alberta, most individuals paired by 3rd winter, normally breed for 1st time at 5 years.*04*. Banko indicates that pairs do not become firmly mated until well into 3rd year of life.*07*. The initial age at which a wild pair begins breeding and nests may be influenced by quantity of unoccupied territory located in suitable nesting habitat.*07*
027 Territory size largely governed by size of water basin.*08*. In Copper River delta, about 150 acres of uninterrupted emergent vegetation/pair, one lake on Kenai supported 2 nest sites nearly 1 mile apart.*08*. At LaCreek NWR, one 320 acre pool provides habitat for 2 nesting pairs.*05*. At Red Rock Lakes refuge, nesting territories contained in single marsh system, highest concentration of nests found: about 70 acre of territory/nesting pair. On less desirable habitat, about 150 acre/nesting pair required.*07*
033 Paired birds have been seen out on snowfields as early as February 2 at Red Rock Lakes. Early occupation of breeding grounds is apparently instinctive.*07*. Arrive by 20 March at Copper River delta and remain abundant until late April. By mid-October all have departed from kenai peninsula, many remain until mid-November at Copper River.*08*. Tend to winter close to breeding grounds when open water available.*08*
035 Potential predators include: raptors, mink, otter, coyote, raccoon, bobcat.*07,08,11*. Predation on adults does not seem to be significant source of mortality in free-living swans.*04,07*. Illegal shooting and lead poisoning are sources of mortality.*04,07* parasites include lice, gizzard worm, roundworm, leeches, trematodes.*07*
099 In alberta, 180-day period required to nest, lay, hatch eggs and fledge cygnets.*04*. Synchronous hatching takes about 24 hours/clutch.*04,08*. Brood moves to water in 1st or 2nd morning post-hatch.*04*. Female may leave nest unattended for varying periods during incubation without detrimental effect.*08*. Age at 1st flight reported as 110 days at yellowstone area, but varies even within broods.*04*. In NE and SD, annual molt occurs July 15-August 10. *05*. In AK, both breeders and nonbreeders remained flightless for average of 30 days after shedding

Life History Information

Territoriality specified in comments(026)
Territory size specified in comments(027)
Mortality rate specified in comments(031)
Turnover rate specified in comments(032)
Migration patterns specified in comments(033)
Limiting factors specified in comments(034)
Regulatory factors specified in comments(035)
Other life history information specified in comments(099)
Origin in state: native
Seasonal distribution in state: spring/fall
Foraging strategy: probing
Foraging strategy: grazing
Foraging sites: water
Foraging sites: feed on bottom of stream, lake or pond
Breeding season specified in comments(007)
Mating system: monogamy
Duration of pair bond: pair for life
Display site: water
Nest/den site: emergent aquatic vegetation
Nest/den site specified in comments(011)
Nest/den/spawning site tenacity specified in comments(013)
Nest materials specified in comments(015)
Nest dimensions specified in comments(016)
Gestation/incubation period specified in comments(017)
Clutch/litter size specified in comments(018)
Number of broods/litter per year: one
Parental care of young: both parents
Age at sexual maturity specified in comments(022)
Territoriality: defends entire breeding, feeding, and nesting territory

Comments about Life History:

Code Comment
015 Nest made of aquatic vegetation.*09,08*
007 In SD, captive swans began courtship display mid-January and continued until mid-March.*11*. Average date for initiation of egg-laying in NE and SD was mid April - mid May, average hatch date: mid May - mid June.*05*. At Copper River delta, data indicated nesting and incubation began as early as 3rd week-April and extended through 1st week in July.*08*
011 Muskrat houses often used as nest sites.*04,05,07*
013 May use same nest site for several years.*09,07,04,08*. 57/74 (77%) nests were located on or within a few feet of previously or subsequently used sites.*07*
026 Behavior characterized by defense of mating, nesting and feeding ground for young, defense of area other than concerned essentially with reproduction not known, interspecific aggressive behavior on nesting territory appears directed chiefly against larger birds.*07*. In AK, territorial maintenance continued from pair's arrival on nest site until well into brood season.*08*
031 Survival on grand prairie, alberta (fledging-1 year) was 42.9%. Majority of mortality apparently occurred during late winter or spring migration. Subadult survival (1 year-2 year) 70.9%.*13*. At Red Rock Lakes, hatching success varied 51-66%.*07*. On kenai, survival (hatching-flight stage) ranged 71-80% over 3 years, average hatching success 79%. At Copper River 55% hatching success.*08*
032 In alberta, it was calculated that each pair must reproduce for 3.8 years to replace pair unit, average life expectancy of adult birds = 5.2 years.*04*
034 In SD, predation became limiting factor in captive swans. Great horned owls, raccoons, bobcats and coyotes were important potential predators.*11*. Overall, seems to be 2 critical limiting factors: lack of breeding habitat and shortage of wintering habitat.*04,05,07,08*
016 Nest usually 6-12' in diameter, some mounds reached as much as 36" in height, mean height of 36 nests in AK = 18", nest cavity 10-16" diameter and 4-8" deep.*08,09*
017 Incubation 33-37 days at Red Rock Lakes refuge, kenai peninsula, and alberta canada.*07,08,04*, 33-35 days at Copper River delta.*08*. In MN, captive swans began hatching 30 days after last egg laid, hatching complete by day 32, cygnets left nest on morning of day 33. *12*
018 7-year mean clutch at Red Rock Lakes refuge 5.1 eggs.*07*. At Copper River, mean clutch 4.9, at kenai, mean clutch 5.3 eggs.*08*. Clutch 4-9 at LaCreek refuge, average 6.4 *05*
022 Successful nesting of at least 3 pairs of swans 33 months old in sd.*08*. Captive birds in SD begyran nesting at 2 years and 9 months.*11*. In alberta, most individuals paired by 3rd winter, normally breed for 1st time at 5 years.*04*. Banko indicates that pairs do not become firmly mated until well into 3rd year of life.*07*. The initial age at which a wild pair begins breeding and nests may be influenced by quantity of unoccupied territory located in suitable nesting habitat.*07*
027 Territory size largely governed by size of water basin.*08*. In Copper River delta, about 150 acres of uninterrupted emergent vegetation/pair, one lake on Kenai supported 2 nest sites nearly 1 mile apart.*08*. At LaCreek NWR, one 320 acre pool provides habitat for 2 nesting pairs.*05*. At Red Rock Lakes refuge, nesting territories contained in single marsh system, highest concentration of nests found: about 70 acre of territory/nesting pair. On less desirable habitat, about 150 acre/nesting pair required.*07*
033 Paired birds have been seen out on snowfields as early as February 2 at Red Rock Lakes. Early occupation of breeding grounds is apparently instinctive.*07*. Arrive by 20 March at Copper River delta and remain abundant until late April. By mid-October all have departed from kenai peninsula, many remain until mid-November at Copper River.*08*. Tend to winter close to breeding grounds when open water available.*08*
035 Potential predators include: raptors, mink, otter, coyote, raccoon, bobcat.*07,08,11*. Predation on adults does not seem to be significant source of mortality in free-living swans.*04,07*. Illegal shooting and lead poisoning are sources of mortality.*04,07* parasites include lice, gizzard worm, roundworm, leeches, trematodes.*07*
099 In alberta, 180-day period required to nest, lay, hatch eggs and fledge cygnets.*04*. Synchronous hatching takes about 24 hours/clutch.*04,08*. Brood moves to water in 1st or 2nd morning post-hatch.*04*. Female may leave nest unattended for varying periods during incubation without detrimental effect.*08*. Age at 1st flight reported as 110 days at yellowstone area, but varies even within broods.*04*. In NE and SD, annual molt occurs July 15-August 10. *05*. In AK, both breeders and nonbreeders remained flightless for average of 30 days after shedding

References for life history: 011 , 012 , 013 , 018 , 001 , 004 , 005 , 007 , 008 , 009

Management

Beneficial Management Practices:

Water - develop/maintain spawning/nesting facilities
Water - develop/maintain wetlands
Water - develop/maintain freshwater marsh
Water - control pollution (thermal, physical, chemical)
Water - control water levels
Water - control aquatic animals
Water - exclude livestock from water
Water - restrict human disturbance
Water - supplemental feeding (winter, spring, etc.)
Water - other (specify in comments)

Beneficial Management References: 020 , 001 , 004 , 005 , 007 , 008

Adverse Managment Practices:

Water - application of pesticides
Water - application of insecticides
Water - dredging and filling
Water - control aquatic plants
Water - drainage of wetlands, marshes, ponds, lakes

Adverse Management References: 001

Comments on Management:
Specific management recommendations: protection and reduction of all disturbance in nesting and wintering areas, public programs to reduce losses through shooting, encouragement of muskrat populations (for nesting sites), encouragement of aquatic vegetation favored by swans for food and cover, fence stock ponds to protect shoreline and emergent vegetation (fences should be placed so to minimize danger of adults and cygnets flying into fence), overhead wires should not cross close to ponds *05,08,04,07*. Large areas of shallow water (1.0-2.5') essential for production of emergent vegetation and for area in which swans can dig and feed. Area of open water about 300' long required for take-off and landing of cygnets.*05*. Stable water levels encourage growth of emergent vegetation. Swans most susceptible to human disturbance during territory establishment and early nesting period (April 15-June 15)*04*. In AK, 6-35 acres more likely to support extensive stands of emergent and floating vegetation.*08*. At red rock lakes refuge, winter habitat was improved through development of warm-water, spring-fed ponds. Muskrat trapping was limited, initiated coyote control, winter feeding of small grain (wheat and barley). Sufficiently protected wintering waters preferable in close proximity to managed breeding grounds.*07*. In MO, at Mingo NWR, an experimental restoration project aimed at re-establishing a wintering population in MO was initiated in 1982, one family group was transplanted from lacreek NWR on September 2, 1982.*01*

References for Management Comments: 001 , 004 , 005 , 006 , 007 , 008

References

Reference Code Citation
001 Unpb Smith, John. Mo Dept. Conserv. 1110 S. College Ave. Columbia, Mo 65201. (573)882-9880.
002 Thom, R.H. and J.H. Wilson. 1980 The Natural Divisions Of Missouri. Trans. Mo Acad. Sci. 14:9-24.
003 American Ornithologists Union. 1957. Checklist Of North American Birds, 5th Ed. Lord Baltimore Press. Baltimore, Md. 691 Pp.
004 Unpb Brechtel, S.H. 1982a Management Plan For Trumpeter Swans In Alberta-1982. Alberta Energy and Nat. Res. Fish and Wildl. Div. 135p.
005 Unpb United States Fish and Wildlife Service. 1982. Management For Lacreek Trumpeter Swans. Manuscript. 36pp.
006 Fjetland, C.A. 1974. Trumpeter Swan Management In The National Wildlife Refuge System. Trans. N.A. Wildl. and Nat. Res. Conf. 39:136-141.
007 Banko, W.E. 1960. The Trumpeter Swan: Its History, Habits, And Population In The United States. N.A. Fauna #63. Bur. Sport Fish. and Wildl., Wash. D.C. 214pp.
008 Hansen, H.A., P.E.K. Shepherd, J. King, and W.A. Troyer. 1971. The Trumpeter Swan In Alaska. Wildl. Monogr. 26. 83pp.
009 Bellrose, F.C. 1980. Ducks, Geese And Swans Of North America, 3rd Ed Stackpole Books. Harrisburg, Pa. 540pp.
010 Mckelvey, R.W. 1980. Winter Habitat And Food Of Cygnus Cygnus Buccinator In British Columbia, Canada. In Proceedings Of 2nd Internat. Swan Symp. Sapporo, Japan.
011 Monnie, J.B. 1966. Reintroduction Of The Trumpeter Swan To Its Former Prairie Breeding Range. J. Wildl. Manage. 30(4):691-696.
012 Cooper, J.A. 1979. Trumpeter Swan Nesting Behaviour. Wildfowl 30:55-71.
013 Unpb Turner, B.C. and R.H. Mackay. (Cited In Ref. 04). The Population Dynamics Of The Trumpeter Swans Of Grande Prairie, Alberta. Rept. Canadian Wildl. Serv. Edmonton, Alberta. 18p.
014 American Ornithologists Union. 1982. Thirty-fourth Supplement To The A.O.U. Checklist Of North American Birds. Auk 99(3):1-16 Cc.
015 The Wildlife Code of Missouri. Missouri Department of Conservation, P.O. Box 180, Jefferson City, MO 65102. 573-751-4115.
016 Checklist Of Rare And Endangered Species Of Missouri. 1991. Mo Dept. Of Conservation. Jefferson City, Mo. 44 Pp.
017 Kelly, G. (Ed.) 1986. Animal Habitat Relations Handbook. Mo Dept. Of Conservation and U.S.D.A. Forest Service. Jefferson City, Mo. 293 Pp.
018 Anderson, D.R., R.C. Hesson, and B. Reiswig. 1986. Estimates Of Annual Survival Rates Of Trumpeter Swans Banded 1949-1982 Near Red Rocks National Wildlife Refuge, Montana. J. Wildl. Manage. 50(2):218-221.
019 Unpb Wilson, J.D. and B. Jacobs. 1988. The Distribution And Breeding Status Of The Birds Of Missouri (Preliminary Report). Mo Dept. Of Conservation, P.O. Box 180, Jefferson City, Mo 65102.
020 Henson, P. and T.A. Grant. 1991. The Effects Of Human Disturbance On Trumpeter Swan Breeding Behavior. Wildl. Soc. Bull. 19:248-257.
021 Grant, T.A., P. Henson and J.A. Cooper. 1994. Feeding Ecology Of Trumpeter Swans Breeding In South Central Alaska. J. Wildl. Manage. 58:774-780.
022 Squires, J.R. and S.H. Anderson. 1995. Trumpeter Swan (Cygnus Buccinator) Food Habits In The Greater Yellowstone Ecosystem. Amer. Midl. Nat. 133:274-282.
023 Easterla, D.A., M.B. Robbins and R.A. Anderson. 1992. Annotated Check-List Of Missouri Birds. The Audubon Society Of Missouri.
024 Jacobs, B. and J.D. Wilson. 1997. Missouri Breeding Bird Atlas 1986-1992. Mo Dept. Of Conservation. Natural History Series No. 6. Jefferson City, Mo. 430 Pp.
025 Missouri Natural Heritage Program. 2001. Missouri Species Of Conservation Concern. Mo Dept. Of Conservation, Jefferson City, Mo. Xi + 28 Pp.
026 Missouri Natural Heritage Program. 2011. Missouri species and communities of conservation concern checklist. Missouri Department of Conservation. Jefferson City, Missouri. pp. 55.