Roadless Areas
Home/Species/ Western Wood-Pewee

Contopus sordidulus

Sclater, 1859

Western Wood-Pewee

G5Secure Found in 335 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
LowThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.104052
Element CodeABPAE32050
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVertebrate Animal
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomAnimalia
PhylumCraniata
ClassAves
OrderPasseriformes
FamilyTyrannidae
GenusContopus
Other Common Names
Pibí Occidental (ES) Pioui de l'Ouest (FR)
Concept Reference
American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online: http://www.aou.org/.
Taxonomic Comments
This species previously was named C. richardsoni (AOU 1998). It has been considered conspecific with C. virens by some authors (AOU 1983). Contopus sordidulus, C. virens, and C. cinereus constitute a superspecies (AOU 1998).
Conservation Status
Rank MethodExpertise without calculation
Review Date2016-04-07
Change Date1996-12-02
Edition Date2009-03-18
Edition AuthorsHammerson, G.
Threat ImpactLow
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences81 to >300
Rank Reasons
Large breeding range mainly in western North America; large population size; relatively stable trend; no major threats.
Range Extent Comments
Breeding range extends from east-central Alaska, southern Yukon, central Mackenzie, central Saskatchewan, and central Manitoba south through western Canada (east to Manitoba) and western United States to southern Baja California and interior highlands of Mexico and Guatemala to Honduras, possibly to northern Nicaragua and Costa Rica (Bemis and Rising 1999). Nonbreeding range extends from Colombia and Venezuela south to Peru and Bolivia, casually northward to Costa Rica (Stiles and Skutch 1989, Bemis and Rising 1999).
Occurrences Comments
This species is represented by a large number of occurrences (subpopulations).
Threat Impact Comments
Certainly habitat loss and degradation has negatively affected local populations, but overall this species does not appear to face any major threats.
Ecology & Habitat

Habitat

Habitat includes forest, forest edge, and woodland, especially coniferous or mixed coniferous-deciduous forest, and poplar or riparian woodland (Subtropical and Temperate zones, in nonbreeding season also Tropical Zone) (AOU 1983). Nests usually are on horizontal branches of living or dead trees, 4-23 meters above ground, sometimes in the fork of a small tree or bush.

Reproduction

Breeding begins in early May in the south, to early June in the north (Harrison 1978). Female incubates 3, sometimes 2-4, eggs for about 12 days.
Terrestrial Habitats
Forest/WoodlandForest - HardwoodForest - ConiferForest - MixedForest EdgeWoodland - HardwoodWoodland - ConiferWoodland - Mixed
Palustrine Habitats
Riparian
Other Nations (2)
CanadaN5B,N4M
ProvinceRankNative
Yukon TerritoryS3BYes
Northwest TerritoriesS3Yes
AlbertaS3BYes
SaskatchewanS4BYes
ManitobaS2BYes
British ColumbiaS5BYes
United StatesN5B
ProvinceRankNative
South DakotaS4BYes
ColoradoS5Yes
Navajo NationS3BYes
North DakotaS4Yes
OregonS4Yes
IdahoS5BYes
OklahomaS1BYes
AlaskaS4BYes
MontanaS5BYes
TexasS4BYes
New MexicoS4B,S5NYes
KansasS1BYes
NebraskaS4Yes
CaliforniaSNRYes
NevadaS3BYes
WyomingS5BYes
UtahS4BYes
WashingtonS5BYes
ArizonaS5Yes
Roadless Areas (335)
Alaska (5)
AreaForestAcres
Chilkat-West Lynn CanalTongass National Forest199,772
HyderTongass National Forest121,723
LindenbergTongass National Forest25,855
North RevillaTongass National Forest215,430
RevillaTongass National Forest29,298
Arizona (22)
AreaForestAcres
Arnold MesaPrescott National Forest12,286
Big RidgeKaibab National Forest9,087
BoulderTonto National Forest40,359
Burro CanyonKaibab National Forest19,928
Butterfly Roadless AreaCoronado National Forest42,296
Catalina St. Pk. Roadless AreaCoronado National Forest951
Cdo WsaCoronado National Forest1,955
CenterfireApache-Sitgreaves National Forests13,130
ChiricahuaCoronado National Forest76,876
GaliuroCoronado National Forest28,333
Lime CreekTonto National Forest42,568
Lower San FranciscoApache-Sitgreaves National Forests59,310
MazatzalTonto National Forest16,942
Middle Dragoon RoadlessCoronado National Forest10,543
NolanApache-Sitgreaves National Forests6,780
Oracle RoadlessCoronado National Forest22,365
PinalenoCoronado National Forest130,920
Pine Mountain Wilderness ContiguousTonto National Forest6,518
PipestemApache-Sitgreaves National Forests34,598
TumacacoriCoronado National Forest44,594
Upper Romero WsrCoronado National Forest150
WhetstoneCoronado National Forest20,728
California (124)
AreaForestAcres
AgnewSequoia National Forest9,561
AntimonyLos Padres National Forest40,911
Arroyo SecoAngeles National Forest4,703
Bald MountainTahoe National Forest5,832
Barker ValleyCleveland National Forest11,940
Bell MeadowStanislaus National Forest7,968
Birch CreekInyo National Forest28,816
Black ButteMendocino National Forest15,461
Black ButteLos Padres National Forest5,116
Black Mtn.Sequoia National Forest15,102
Bucks LakePlumas National Forest680
CajonSan Bernardino National Forest7,548
CalienteCleveland National Forest5,953
Caples CreekEldorado National Forest17,854
Carson - IcebergStanislaus National Forest56,430
Castle PeakTahoe National Forest14,974
ChanchelullaShasta-Trinity National Forest3,915
ChannellSequoia National Forest45,429
Cherry LakeStanislaus National Forest1,106
ChicoSequoia National Forest39,836
Chips CreekPlumas National Forest12,940
Chips CreekLassen National Forest29,089
City CreekSan Bernardino National Forest9,997
ColdwaterCleveland National Forest8,402
Coyote NorthInyo National Forest11,932
Coyote SoutheastInyo National Forest53,159
Crystal CreekSan Bernardino National Forest6,783
Cucamonga AAngeles National Forest1,249
Cucamonga BSan Bernardino National Forest11,933
Cutca ValleyCleveland National Forest14,530
CuyamaLos Padres National Forest19,631
Damon ButteModoc National Forest25,022
DardanellesEldorado National Forest8,110
Deep CreekSan Bernardino National Forest23,869
Devil GulchSierra National Forest30,490
Dinkey LakesSierra National Forest34,171
DomeStanislaus National Forest11,085
Domeland Add.Sequoia National Forest3,046
Dry LakesLos Padres National Forest17,043
Duncan CanyonTahoe National Forest8,621
EagleStanislaus National Forest16,116
East YubaTahoe National Forest17,968
Ferguson RidgeSierra National Forest6,104
Fox MountainLos Padres National Forest52,072
Glass MountainInyo National Forest52,867
Granite ChiefTahoe National Forest6,546
Granite PeakSan Bernardino National Forest450
GrindstoneMendocino National Forest26,031
Hall Natural AreaInyo National Forest5,236
Heart LakeLassen National Forest9,349
Hoover - Green Ck NoHumboldt-Toiyabe National Forest7,155
Hoover - Mt.olsenHumboldt-Toiyabe National Forest624
Hoover - NorthHumboldt-Toiyabe National Forest1,574
Hoover - Twin LakesHumboldt-Toiyabe National Forest102
Hoover - Virginia LksHumboldt-Toiyabe National Forest5,050
Horse Creek RidgeSan Bernardino National Forest8,969
Horse Mdw.Inyo National Forest5,687
HortonInyo National Forest5,717
Iceberg - Mill CreekHumboldt-Toiyabe National Forest26,988
IshiLassen National Forest21,805
Kings RiverSierra National Forest52,999
Log Cabin SaddlebagInyo National Forest15,165
Middle ForkPlumas National Forest29,278
Middle YubaTahoe National Forest7,379
Mill CreekLassen National Forest7,587
Mill PeakSan Bernardino National Forest7,884
MonarchSierra National Forest697
Mt. BidwellModoc National Forest11,687
Mt. LassicSix Rivers National Forest6,643
Mt. OlsenInyo National Forest2,161
Mt. VidaModoc National Forest7,771
Nevahbe RidgeInyo National Forest302
NightStanislaus National Forest3,173
No NameCleveland National Forest4,897
NordhoffLos Padres National Forest12,031
North Fork American RiverTahoe National Forest38,495
North Fork SmithSix Rivers National Forest37,898
North LakeInyo National Forest2,406
Onion SpringsLassen National Forest2,421
PacksaddleSix Rivers National Forest3,862
Pine CreekCleveland National Forest503
Pleasant ViewAngeles National Forest26,395
Poison HoleEldorado National Forest2,627
PyramidEldorado National Forest24,347
Pyramid Peak BSan Bernardino National Forest7,194
Raymond PeakStanislaus National Forest3,646
Raymond PeakEldorado National Forest2,518
Raywood Flat BSan Bernardino National Forest11,373
RinconSequoia National Forest54,610
Robinson PeakHumboldt-Toiyabe National Forest5,835
Rock Creek WestInyo National Forest3,626
Rouse HillSan Bernardino National Forest13,745
Salt GulchShasta-Trinity National Forest6,511
San Gabriel AddAngeles National Forest2,527
San JoaquinSierra National Forest22,474
Sawmill - BadlandsLos Padres National Forest51,362
Sespe - FrazierLos Padres National Forest106,910
Sheep MountainAngeles National Forest21,098
SherwinInyo National Forest3,140
Sill HillCleveland National Forest5,294
Silver HillHumboldt-Toiyabe National Forest4,423
SinkardHumboldt-Toiyabe National Forest2,004
Slate Mtn.Sequoia National Forest12,299
Soldier CanyonInyo National Forest40,589
South ForkShasta-Trinity National Forest16,786
South SierraSequoia National Forest8,008
South SierraInyo National Forest41,853
Strawberry PeakAngeles National Forest7,245
SugarloafSan Bernardino National Forest8,206
Table Mtn.Inyo National Forest4,215
TinemahaInyo National Forest27,060
Tioga LakeInyo National Forest829
Tragedy - Elephants BackEldorado National Forest20,866
Trail LakeLassen National Forest1,124
Trumbull PeakStanislaus National Forest6,164
WestforkAngeles National Forest4,407
Wheeler RidgeInyo National Forest15,744
Whisky CreekInyo National Forest865
Wild Cattle MtnLassen National Forest4,965
Wild Horse Mtn. (CA)Humboldt-Toiyabe National Forest28,822
Wilderness ContiguousMendocino National Forest3,606
Wonoga Pk.Inyo National Forest11,272
WoodpeckerSequoia National Forest11,936
WoolstaffSequoia National Forest41,445
Colorado (7)
AreaForestAcres
Bristol HeadRio Grande NF46,087
Comanche Peak Adjacent AreaArapaho & Roosevelt NFs44,158
Dome PeakRoutt NF35,716
HermosaSan Juan NF148,103
Long ParkRoutt NF42,100
Pagoda PeakRoutt NF57,676
Red TableWhite River NF39,122
Idaho (7)
AreaForestAcres
Borah PeakSalmon-Challis National Forest130,463
HoodooNez Perce-Clearwater National Forest153,868
Lemhi RangeSalmon-Challis National Forest308,533
PalisadesCaribou-Targhee National Forest122,002
Peace RockBoise National Forest191,734
Pioneer MountainsSawtooth National Forest119,563
Pioneer MountainsSalmon-Challis National Forest172,460
Montana (27)
AreaForestAcres
Basin CreekBeaverhead-Deerlodge National Forest9,500
Bear - Marshall - Scapegoat - SwanLewis and Clark National Forest344,022
Big LogHelena National Forest8,954
Bmss Ra 1485Flathead National Forest334,275
Buckhorn Ridge (MT)Kootenai National Forest34,716
Cabinet Face East #671Kootenai National Forest50,326
Cube Iron - SilcoxLolo National Forest36,998
East PioneerBeaverhead-Deerlodge National Forest145,082
ElkhornHelena National Forest75,468
Freezeout MountainBeaverhead-Deerlodge National Forest97,305
HolterHelena National Forest1,965
Jerico MountainHelena National Forest8,445
Lost Water CanyonCuster National Forest9,251
MadisonGallatin National Forest127,859
Mt. Gmt Area HCuster National Forest1,335
North AbsarokaGallatin National Forest159,075
North AbsarokaCuster National Forest21,063
North SiegelLolo National Forest9,208
Patricks Knob - North CutoffLolo National Forest16,970
QuiggLolo National Forest67,267
Reservation DivideLolo National Forest16,908
Scotchman Peaks (MT)Kootenai National Forest53,909
Selway - Bitterroot (01067)Bitterroot National Forest114,953
Sheep Mountain - StatelineLolo National Forest37,844
Silver KingBeaverhead-Deerlodge National Forest64,289
South Siegel - South CutoffLolo National Forest13,474
West PioneerBeaverhead-Deerlodge National Forest248,631
Nevada (18)
AreaForestAcres
Angel Peak NorthHumboldt-Toiyabe National Forest12,577
Arc Dome - Secret BsnHumboldt-Toiyabe National Forest74,782
Aurora CraterHumboldt-Toiyabe National Forest5,689
Boundary Peak (NV)Inyo National Forest21,851
Humboldt - Angel LkHumboldt-Toiyabe National Forest1,008
Jarbidge - West ForkHumboldt-Toiyabe National Forest2,725
North Shoshone PeakHumboldt-Toiyabe National Forest40,667
Pearl PeakHumboldt-Toiyabe National Forest71,405
QuinnHumboldt-Toiyabe National Forest62,459
Rose - EvansHumboldt-Toiyabe National Forest4,782
Rose - GalenaHumboldt-Toiyabe National Forest3,711
Rose - Whites CanyonHumboldt-Toiyabe National Forest2,568
Ruby - Lamoille CynHumboldt-Toiyabe National Forest32,771
Ruby - SouthHumboldt-Toiyabe National Forest13,195
Ruby - ThompsonHumboldt-Toiyabe National Forest5,289
Snake - Big WashHumboldt-Toiyabe National Forest4,146
Snake - ChokecherryHumboldt-Toiyabe National Forest30,845
Snake - HatcheryHumboldt-Toiyabe National Forest4,627
New Mexico (29)
AreaForestAcres
Alamo CanyonSanta Fe National Forest8,639
Black CanyonSanta Fe National Forest1,922
Bull CanyonCarson National Forest11,512
Canyon CreekGila National Forest9,824
Capitan MountainsLincoln National Forest14,069
Columbine - Hondo Wilderness Study AreaCarson National Forest43,739
Contiguous To Black & Aldo Leopold WildernessGila National Forest111,883
Contiguous To Gila Wilderness & Primitive AreaGila National Forest79,049
Devils CreekGila National Forest89,916
Frisco BoxGila National Forest38,979
GallinasSanta Fe National Forest13,208
Gila BoxGila National Forest23,759
Grass MountainSanta Fe National Forest3,254
Jacks CreekSanta Fe National Forest740
Jefferies CanyonLincoln National Forest8,934
Lower San FranciscoGila National Forest26,460
Meadow CreekGila National Forest34,167
Nichols ReservoirSanta Fe National Forest1,518
NolanGila National Forest13,051
Pecos WS RiverSanta Fe National Forest5,396
Peloncillo (NM)Coronado National Forest43,339
Ryan HillCibola National Forest34,201
Sawyers PeakGila National Forest59,743
South Guadalupe MountainsLincoln National Forest20,930
Tesuque CreekSanta Fe National Forest810
Thompson PeakSanta Fe National Forest33,001
Virgin CanyonSanta Fe National Forest6,068
West Face Sacramento MountainsLincoln National Forest41,176
Wheeler Peak WildernessCarson National Forest2,677
Oregon (15)
AreaForestAcres
Coleman RimFremont National Forest10,638
Crane MountainFremont National Forest23,096
Drift CreekSiuslaw National Forest6,333
HellholeUmatilla National Forest65,679
HomesteadWallowa-Whitman National Forest5,817
Hurricane CreekWallowa-Whitman National Forest1,606
Imnaha FaceWallowa-Whitman National Forest29,575
Joseph CanyonWallowa-Whitman National Forest24,288
LookingglassUmatilla National Forest4,859
Lookout MountainOchoco National Forest14,115
Mt. JeffersonDeschutes National Forest2,282
Sheep DivideWallowa-Whitman National Forest16,201
Sky Lakes AWinema National Forest3,940
Walla Walla RiverUmatilla National Forest34,416
WoahinkSiuslaw National Forest5,309
South Dakota (1)
AreaForestAcres
Indian CreekBuffalo Gap National Grassland24,666
Utah (33)
AreaForestAcres
0401001Ashley National Forest11,705
0401005Ashley National Forest38,930
0401024Ashley National Forest12,882
0419020Ashley National Forest355,684
418001Uinta National Forest5,697
418014Uinta National Forest9,683
418016Uinta National Forest35,240
418025Uinta National Forest32,698
418026Uinta National Forest14,038
418028Uinta National Forest34,002
418029Uinta National Forest15,673
Boulder Mtn. / Boulder Top / Deer LakeDixie National Forest110,690
Capital ReefDixie National Forest763
Circleville MountainFishlake National Forest24,142
Clarkston Mtn.Caribou National Forest7,099
FishhookDixie National Forest12,959
Fishlake MountainFishlake National Forest25,217
HancockDixie National Forest9,809
High Uintas (UT)Wasatch-Cache National Forest102,398
Joe LottFishlake National Forest19,826
LakesWasatch-Cache National Forest121,967
Lava BedsDixie National Forest14,944
Lewis PeakWasatch-Cache National Forest11,616
Lone Peak ContiguousWasatch-Cache National Forest874
Mt. AireWasatch-Cache National Forest9,681
Mt. OlympusWasatch-Cache National Forest9,982
NoblettsWasatch-Cache National Forest3,116
Pine Valley MountainsDixie National Forest57,673
Red Canyon NorthDixie National Forest9,973
Signal PeakFishlake National Forest30,889
South FrancisWasatch-Cache National Forest3,374
Table Cliffs - Henderson CanyonDixie National Forest19,581
Twin PeaksWasatch-Cache National Forest6,157
Washington (21)
AreaForestAcres
Black CanyonOkanogan National Forest9,681
Boulder RiverMt Baker-Snoqualmie National Forest32,563
ChelanWenatchee National Forest74,650
Devils GulchWenatchee National Forest24,419
EntiatWenatchee National Forest72,617
Glacier Peak JMt Baker-Snoqualmie National Forest26,482
Glacier Peak KMt Baker-Snoqualmie National Forest47,269
Goat Rocks AdjWenatchee National Forest6,108
Granite MountainOkanogan National Forest27,428
Higgins MountainMt Baker-Snoqualmie National Forest13,185
Liberty BellOkanogan National Forest108,495
ManastashWenatchee National Forest11,155
Mill Creek Watershed (WA)Umatilla National Forest16,747
Nason RidgeWenatchee National Forest19,329
Norse PeakWenatchee National Forest10,169
Pasayten RimOkanogan National Forest17,074
QuartzWenatchee National Forest8,550
Rock CreekWenatchee National Forest32,239
Salmo - Priest BColville National Forest11,869
SawtoothOkanogan National Forest122,194
TaneumWenatchee National Forest26,140
Wyoming (26)
AreaForestAcres
0401036Ashley National Forest6,309
Beartooth Proposed WildernessShoshone National Forest16,837
Canyon CreekShoshone National Forest7,530
Cloud Peak ContiguousBighorn National Forest113,757
French CreekMedicine Bow-Routt National Forest5,928
Grayback RidgeBridger-Teton National Forest295,113
Gros Ventre MountainsBridger-Teton National Forest106,418
Horse Creek MesaBighorn National Forest77,808
Leigh CreekBighorn National Forest19,180
Libby FlatsMedicine Bow-Routt National Forest11,107
Middle ForkMedicine Bow-Routt National Forest13,238
Middle ForkShoshone National Forest51,772
Mosquito Lake - Seven LakesBridger-Teton National Forest51,950
Munger MountainBridger-Teton National Forest12,827
PalisadesTarghee National Forest1,121
Piney CreekBighorn National Forest22,240
Rock CreekBighorn National Forest48,657
Salt River RangeBridger-Teton National Forest235,661
Sheep MountainMedicine Bow-Routt National Forest17,626
Snowy RangeMedicine Bow-Routt National Forest29,660
South Beartooth HighwayShoshone National Forest105,570
Spread Creek - Gros Ventre RiverBridger-Teton National Forest166,097
Teton Corridor TrailheadsBridger-Teton National Forest286
West Slope TetonsTarghee National Forest47,448
West Slope WindsBridger-Teton National Forest143,252
Wilderness Study AreaTarghee National Forest51,961
References (29)
  1. American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp.
  2. American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in <i>The Auk</i>]. Also available online: http://www.aou.org/.
  3. Balda, R. P., and G. C. Bateman. 1971. Flocking and annual cycle of the piñon jay, <i>Gymnorhinus cyanocephalus</i>. Condor 73:287-302.
  4. Bemis, C., and J. D. Rising. 1999. Western wood-pewee (<i>Contopus sordidulus</i>). In A. Poole and F. Gill, editors. The Birds of North America, No. 451. The Birds of North America, Inc., Philadelphia, PA. 20 pp.
  5. BirdLife International. 2004b. Threatened birds of the world 2004. CD ROM. BirdLife International, Cambridge, UK.
  6. Carter, M., G. Fenwick, C. Hunter, D. Pashley, D. Petit, J. Price, and J. Trapp. 1996. Watchlist 1996: For the future. Field Notes 50(3):238-240.
  7. Godfrey, W.E. 1966. The birds of Canada. National Museums of Canada. Ottawa. 428 pp.
  8. Hagan, J. M., III, and D. W. Johnston, editors. 1992. Ecology and conservation of neotropical migrant landbirds. Smithsonian Institution Press, Washington, D.C. xiii + 609 pp.
  9. Harrison, C. 1978. A Field Guide to the Nests, Eggs and Nestlings of North American Birds. Collins, Cleveland, Ohio.
  10. Hilty, S.L. and W. L. Brown. 1986. A Guide to the Birds of Colombia. Princeton University Press, Princeton, USA. 836 pp.
  11. Horn, H. S. 1968. The adaptive significance of colonial nesting in the Brewer's Blackbird. Ecology 49:682-694.
  12. Howell, S. N. G., and S. Webb. 1995. A guide to the birds of Mexico and northern Central America. Oxford University Press, Oxford, UK.
  13. Ligon, J. D. 1971. Late summer-autumnal breeding of the piñon jay in New Mexico. Condor 73:147-153.
  14. Moore, W. S., and R. A. Dolbeer. 1989. The use of banding recovery data to estimate dispersal rates and gene flow in avian species: case studies in the Red-winged Blackbird and Common Grackle. Condor 91:242-253.
  15. National Geographic Society (NGS). 1983. Field guide to the birds of North America. National Geographic Society, Washington, DC.
  16. Oberholser, H.C. 1974. The bird life of Texas. 2 vols. Univ. of Texas Press, Austin.
  17. Parker III, T. A., D. F. Stotz, and J. W. Fitzpatrick. 1996. Ecological and distributional databases for neotropical birds. The University of Chicago Press, Chicago.
  18. Raffaele, H., J. Wiley, O. Garrido, A. Keith, and J. Raffaele. 1998. A guide to the birds of the West Indies. Princeton University Press, Princeton, NJ. 511 pp.
  19. Rich, T. D., C. J. Beardmore, H. Berlanga, P. J. Blancher, M.S.W. Bradstreet, G. S. Butcher, D. W. Demarest, E. H. Dunn, W. C. Hunter, E. E. Iñigo-Elias, A. M. Martell, A. O. Panjabi, D. N. Pashley, K. V. Rosenberg, C. M. Rustay, J. S. Wendt, T. C. Will. 2004. Partners in Flight North American landbird conservation plan. Cornell Lab of Ornithology. Ithaca, NY. Online. Available: <u><http://www.partnersinflight.org/cont_plan/></u>
  20. Ridgely, R. S. 2002. Distribution maps of South American birds. Unpublished.
  21. Ridgely, R. S. and J. A. Gwynne, Jr. 1989. A Guide to the Birds of Panama. 2nd edition. Princeton University Press, Princeton, USA.
  22. Sauer, J.R., and S. Droege. 1992. Geographical patterns in population trends of Neotropical migrants in North America. Pages 26-42 in J.M. Hagan, III, and D.W. Johnston, editors. Ecology and conservation of Neotropical migrant landbirds. Smithsonian Institution Press, Washington, DC.
  23. Stiles, F. G. and A. F. Skutch. 1989. A guide to the birds of Costa Rica. Cornell University Press, Ithaca, New York, USA. 511 pp.
  24. Tarvin, K. A., and G. E. Woolfenden. 1999. Blue Jay (<i>Cyanocitta cristata</i>). No. 469 IN A. Poole and F. Gill, editors. The birds of North America. The Birds of North America, Inc., Philadelphia, PA. 32pp.
  25. Terres, J. K. 1980. The Audubon Society encyclopedia of North American birds. Alfred A. Knopf, New York.
  26. Thompson, F. R., III. 1994. Temporal and spatial patterns of breeding brown-headed cowbirds in the midwestern United States. Auk 111:979-990.
  27. Williams, L. 1952b. Breeding behavior of the Brewer blackbird. Condor 54:3-47.
  28. Willson, M. F. 1966. Breeding ecology of the Yellow-headed Blackbird. Ecological Monographs 36:51-77.
  29. Zook, J. L. 2002. Distribution maps of the birds of Nicaragua, Costa Rica, and Panama. Unpublished.