, Volume 142, Issue 1, pp 136–149 | Cite as

Density-dependent habitat selection by brown-headed cowbirds (Molothrus ater) in tallgrass prairie

  • William E. JensenEmail author
  • Jack F. CullyJr
Behavioural Ecology


Local distributions of avian brood parasites among their host habitats may depend upon conspecific parasite density. We used isodar analysis to test for density-dependent habitat selection in brown-headed cowbirds (Molothrus ater) among tallgrass prairie adjacent to wooded edges, and prairie interior habitat (>100 m from wooded edges) with and without experimental perches. Eight study sites containing these three habitat treatments were established along a geographical gradient in cowbird abundance within the Flint Hills region of Eastern Kansas and Oklahoma, USA. The focal host species of our study, the dickcissel (Spiza americana), is the most abundant and preferred cowbird host in the prairie of this region. Cowbird relative abundance and cowbird:host abundance ratios were used as estimates of female cowbird density, whereas cowbird egg density was measured as parasitism frequency (percent of dickcissel nests parasitized), and parasitism intensity (number of cowbird eggs per parasitized nest). Geographical variation in cowbird abundance was independent of host abundance. Within study sites, host abundance was highest in wooded edge plots, intermediate in the experimental perch plots, and lowest in prairie interior. Cowbirds exhibited a pattern of density-dependent selection of prairie edge versus experimental perch and interior habitats. On sites where measures of cowbird density were lowest, all cowbird density estimates (female cowbirds and their eggs) were highest near (≤100 m) wooded edges, where host and perch availability are highest. However, as overall cowbird density increased geographically, these density estimates increased more rapidly in experimental perch plots and prairie interiors. Variation in cowbird abundance and cowbird:host ratios suggested density-dependent cowbird selection of experimental perch over prairie interior habitat, but parasitism levels on dickcissel nests were similar among these two habitats at all levels of local cowbird parasitism. The density-dependent pattern of cowbird distribution among prairie edge and interior suggested that density effects on perceived cowbird fitness are greatest at wooded edges. A positive relationship between daily nest mortality rates of parasitized nests during the nestling period with parasitism intensity levels per nest suggested a density-dependent effect on cowbird reproductive success. However, this relationship was similar among habitats, such that all habitats should have been perceived as being equally suitable to cowbirds at all densities. Other unmeasured effects on cowbird habitat suitability (e.g., reduced cowbird success in edge-dwelling host nests, cowbird despotism at edges) might have affected cowbird habitat selection. Managers attempting to minimize cowbird parasitism on sensitive cowbird hosts should consider that hosts in otherwise less-preferred cowbird habitats (e.g., habitat interiors) are at greater risk of being parasitized where cowbirds become particularly abundant.


Edge effects Ideal free distribution Isodar Molothrus ater Spiza americana 



Many thanks to Jarrod Bowers, Drew Miller, Justin Fletcher, Sean Cordill, Tracy Dick, Matt McGregor, and Sheila Santos for field assistance. Assistance from the staff at Konza Prairie Biological Station (Kansas State University, The Nature Conservancy), the Tallgrass Prairie Preserve (The Nature Conservancy), the Kansas Department of Wildlife and Parks, and the US Army Corps of Engineers was much appreciated. The manuscript was improved from suggestions made by C. Dustin Becker, Brett Sandercock, Christopher Smith, D. Rintoul, Scott Robinson, and two anonymous reviewers. Edward Peltzer provided statistical assistance. This study was funded by grants from the Kansas Department of Wildlife and Parks, and received additional support from the Division of Biology at Kansas State University and the Kansas Cooperative Fish and Wildlife Research Unit.


  1. Alvarez F (1993) Proximity of trees facilitates parasitism by cuckoos Cuculus canorus on rufous warblers. Ibis 135:331Google Scholar
  2. Bult TP, Riley SC, Haedrich RL, Gibson RJ, Heggenes J (1999) Density-dependent habitat selection by juvenile Atlantic salmon (Salmo salar) in experimental riverine habitats. Can J Fish Aquat Sci 56:1298–1306CrossRefGoogle Scholar
  3. Chalfoun AD, Thompson FR III, Ratnaswamy MJ (2002) Nest predators and fragmentation: a review and meta-analysis. Conserv Biol 16:306–318CrossRefGoogle Scholar
  4. Clotfelter ED (1998) What cues do brown-headed cowbirds use to locate red-winged blackbird host nests? Anim Behav 55:1181–1189CrossRefPubMedGoogle Scholar
  5. Cully J, Egbert S, Harrington J, Hornemann T, Kaufman G, Lauver C, Martinko E, Price K (2002) A gap analysis of Kansas. Kansas Cooperative Fish and Wildlife Research Unit, ManhattanGoogle Scholar
  6. Curson DR, Mathews NE (2003) Reproductive costs of commuting flights in brown-headed cowbirds. J Wildl Manage 67:520–529Google Scholar
  7. Dearborn DC (1999) Brown-headed cowbird nestling vocalizations and risk of nest predation. Auk 116:448–457Google Scholar
  8. Dearborn DC, Lichtenstein G (2002) Begging behaviour and host exploitation in parasitic cowbirds. In: Wright J, Leonard ML (eds) The evolution of begging: competition, cooperation and communication. Kluwer, Dordrecht, pp 361–387Google Scholar
  9. Donovan TM, Jones PW, Annand EM, Thompson FR III (1997) Variation in local-scale edge effects: mechanisms and landscape context. Ecology 78:2064–2075Google Scholar
  10. Donovan TM, Thompson FR III, Faaborg JR (2000) Cowbird distribution at different scales of fragmentation: trade-offs between feeding and breeding opportunities. In: Smith JNM, Cook TL, Rothstein SI, Robinson SK, Sealy SG (eds) Ecology and management of cowbirds and their hosts. University of Texas Press, Austin, pp 255–264Google Scholar
  11. Elliott PF (1977) Adaptive significance of cowbird egg distribution. Auk 94:590–593Google Scholar
  12. Elliott PF (1978) Cowbird parasitism in the Kansas tallgrass prairie. Auk 95:161–167Google Scholar
  13. Elliott PF (1980) Evolution of promiscuity in the brown-headed cowbird. Condor 82:138–141Google Scholar
  14. Fernández-Juric E (2001) Density-dependent habitat selection of corridors in a fragmented landscape. Ibis 143:278–287Google Scholar
  15. Fleischer RC (1985) A new technique to identify and assess the dispersion of eggs of individual brood parasites. Behav Ecol Sociobiol 17:91–99Google Scholar
  16. Freeman S, Gori DF, Rohwer S (1990) Red-winged blackbirds and brown-headed cowbirds: some aspects of a host parasite relationship. Condor 92:336–340Google Scholar
  17. Fretwell SD (1972) Populations in a seasonal environment. Princeton University Press, PrincetonGoogle Scholar
  18. Fretwell SD, Lucas HL Jr (1970) On territorial behavior and other factors influencing habitat distribution in birds. Acta Biotheor 19:16–36Google Scholar
  19. Friedman HL, Kiff LF (1985) The parasitic cowbirds and their hosts. Proc West Found Zool 2:226–304Google Scholar
  20. Goguen CB, Mathews NE (2000) Local gradients of cowbird abundance and parasitism relative to livestock grazing in a western landscape. Conserv Biol 14:1862–1869CrossRefGoogle Scholar
  21. Hahn DC, Sedgewick JA, Painter IS, Casna NJ (1999) A spatial and genetic analysis of cowbird host selection. Stud Avian Biol 18:204–217Google Scholar
  22. Hatch SA (1983) Nestling growth relationships of brown-headed cowbirds and dickcissels. Wilson Bull 95:669–671Google Scholar
  23. Hauber ME, Russo SA (2000) Perch proximity correlates with higher rates of cowbird parasitism of ground nesting song sparrows. Wilson Bull 112:150–153Google Scholar
  24. Herkert JR, Reinking DL, Wiedenfeld DA, Winter M, Zimmerman JL, Jensen WE, Finck EJ, Koford RR, Wolfe DH, Sherrod SK, Jenkins MA, Faaborg J, Robinson SK (2003) Effects of prairie fragmentation on the nest success of breeding birds in the mid-continental United States. Conserv Biol 17:587–594CrossRefGoogle Scholar
  25. Hosoi SA, Rothstein SI (2000) Nest desertion and cowbird parasitism: evidence for evolved responses and evolutionary lag. Anim Behav 59:823–840CrossRefPubMedGoogle Scholar
  26. Jensen WE (1999) Nesting habitat and responses to habitat edges of three grassland passerine species. MS Thesis, Emporia State University, Kan.Google Scholar
  27. Jensen WE (2003) Spatial variation in brown-headed cowbird (Molothrus ater) Abundance and brood parasitism in flint hills tallgrass prairie. PhD Dissertation, Kansas State UniversityGoogle Scholar
  28. Jensen WE, Finck EJ (2004) Edge effects on nesting dickcissels (Spiza americana) in relation to edge type of remnant tallgrass prairie in Kansas. Am Midl Nat 151:192–199Google Scholar
  29. Johnsgard PA (1997) The avian brood parasites: deception at the nest. Oxford University Press, OxfordGoogle Scholar
  30. Johnson RG, Temple SA (1990) Nest predation and brood parasitism of tallgrass prairie birds. J Wildl Manage 54:106–111Google Scholar
  31. Kershner EL, Bollinger EK (1998) Low incidence of cowbird parasitism of grassland birds on Illinois airports. Trans Illinois State Acad Sci 91:103–107Google Scholar
  32. Koford RR, Bowen BS, Lokemoen JT, Kruse AD (2000) Cowbird parasitism in grassland and cropland in the Northern Great Plains. In: Smith JNM, Cook TL, Rothstein SI, Robinson SK, Sealy SG (eds) Ecology and management of cowbirds and their hosts. University of Texas Press, Austin, pp 229–235Google Scholar
  33. Krasnov BR, Khokhlova IS, Shenbrot GI (2002) Density-dependent host selection in ectoparasites: an application of isodar theory to fleas parasitizing rodents. Oecologia 134:365–372PubMedGoogle Scholar
  34. Krebs CJ (1989) Ecological methodology. Harper and Row, New YorkGoogle Scholar
  35. Lowther PE (1993) Brown-headed cowbird (Molothrus ater). In: Poole A, Gill F (eds) The birds of North America, no. 47. The Birds of North America, Philadelphia, Pa.Google Scholar
  36. Marshall CT, Frank KT (1995) Density-dependent habitat selection by juvenile haddock (Melanogrammus aeglefinus) on the southwestern Scotian Shelf. Can J Fish Aquat Sci 52:1007–1017CrossRefGoogle Scholar
  37. Martin TE (1995) Avian life history evolution in relation to nest sites, nest predation, and food. Ecol Monogr 65:101–127Google Scholar
  38. Martin TE, Scott J, Menge C (2000) Nest predation increases with parental activity: separating nest site and parental activity effects. Proc R Soc Lond B 267:2287–2293CrossRefPubMedGoogle Scholar
  39. Mayfield HF (1965) Chance distribution of cowbird eggs. Condor 67:257–263Google Scholar
  40. Mayfield HF (1975) Suggestions for calculating nest success. Wilson Bull 87:456–466Google Scholar
  41. McGeen DS (1972) Cowbird-host relationships. Auk 89:360–380Google Scholar
  42. McLaren CM, Woolfenden BE, Gibbs HL, Sealy SG (2003) Genetic and temporal patterns of multiple parasitism by brown-headed cowbirds (Molothurs ater) on song sparrows (Melospiza melodia). Can J Zool 81:281–286CrossRefGoogle Scholar
  43. Messier F, Virgl JA, Marinelli L (1990) Density-dependent habitat selection in muskrats: a test of the ideal free distribution model. Oecologia 84:380–385Google Scholar
  44. Morris DW (1988) Habitat-dependent population regulation and community structure. Evol Ecol 2:253–269Google Scholar
  45. Morris DW (2003) Toward an ecological synthesis: a case for habitat selection. Oecologia 136:1–13CrossRefPubMedGoogle Scholar
  46. Normon RF, Robertson RJ (1975) Nest-searching behavior in the brown-headed cowbird. Auk 92:610–611Google Scholar
  47. O’Connor RJ (1986) Dynamical aspects of avian habitat use. In: Verner J, Morrison ML, Ralph CJ (eds) Wildlife 2000: modeling habitat relationships of terrestrial vertebrates. University of Wisconsin Press, Madison, pp 235–240Google Scholar
  48. θien IJ, Honza M, Moksnes A, Roskaft E (1996) The risk of parasitism in relation to the distance from reed warbler nests to cuckoo perches. J Anim Ecol 65:147–153Google Scholar
  49. Ortega CP, Ortega JC, Cruz A (1994) Use of artificial brown-headed cowbird eggs as a potential management tool in deterring parasitism. J Wildl Manage 58:488–492Google Scholar
  50. Parker TH (1999) Responses of Bells’ vireos to brood parasitism by the brown-headed cowbird in Kansas. Wilson Bull 111:499–504Google Scholar
  51. Peer BD, Robinson SK, Herkert JR (2000) Egg rejection by cowbird hosts in grasslands. Auk 117:892–901Google Scholar
  52. Peterjohn BG, Sauer JR, Schwarz S (2000) Temporal and geographic patterns in population trends of brown-headed cowbirds. In: Smith JNM, Cook TL, Rothstein SI, Robinson SK, Sealy SG (eds) Ecology and management of cowbirds and their hosts. University of Texas Press, Austin, pp 21–34Google Scholar
  53. Pulliam HR, Danielson BJ (1991) Sources, sinks, and habitat selection: a landscape perspective on population dynamics. Am Nat 137:S50-S66CrossRefGoogle Scholar
  54. Ricker WE (1973) Linear regression in fishery research. J Fish Res Board Can 30:409–434Google Scholar
  55. Robinson SK (1999) Cowbird ecology: factors affecting the abundance and distribution of cowbirds. Stud Avian Biol 18:4–9Google Scholar
  56. Robinson SK, Brawn JD, Morse SF, Herkert JR (1999) Use of different habitats by breeding brown-headed cowbirds in fragmented Midwestern landscapes. Stud Avian Biol 18:52–61Google Scholar
  57. Robinson SK, Hoover JP, Herkert JR (2000) Cowbird parasitism in a fragmented landscape: effects of tract size, habitat, and abundance of cowbirds and hosts. In: Smith JNM, Cook TL, Rothstein SI, Robinson SK, Sealy SG (eds) Ecology and management of cowbirds and their hosts. University of Texas Press, Austin, pp 280–297Google Scholar
  58. Rothstein SI, Cook TL (2000) Introduction to ‘Cowbird management, host population limitation, and efforts to save endangered species.’ In: Smith JNM, Cook TL, Rothstein SI, Robinson SK, Sealy SG (eds) Ecology and management of cowbirds and their hosts. University of Texas Press, Austin, pp 323–332Google Scholar
  59. Rothstein, SI, Yokel DA, Fleischer RC (1986) Social dominance mating and spacing systems, female fecundity, and vocal dialects in captive and free-ranging brown-headed cowbirds. Curr Ornithol 3:127–185Google Scholar
  60. Shenbrot G, Krasnov B (2000) Habitat selection along an environmental gradient: theoretical models with an example of Negev Desert rodents. Evol Ecol Res 2:257–277Google Scholar
  61. Shochat E, Abramsky Z, Pinshow B, Whitehouse MEA (2002) Density-dependent habitat selection in migratory passerines during stopover: what causes the deviation from IFD? Evol Ecol 16:469–488CrossRefGoogle Scholar
  62. Strausberger BM, Ashley MV (1997) Community-wide patterns of parasitism of a host “generalist” brood parasitic cowbird. Oecologia 112:254–262CrossRefGoogle Scholar
  63. Strausberger BM, Ashley MV (2001) Eggs yield nuclear DNA from egg-laying female cowbirds, their embryos and offspring. Conserv Gen 2:385–390CrossRefGoogle Scholar
  64. Strausberger BM, Ashley MV (2003) Breeding biology of brood parasitic brown-headed cowbirds (Molothrus ater) characterized by parent-offspring and sibling-group reconstruction. Auk 120:433–445Google Scholar
  65. Sutherland WJ, Parker GA (1985) Distribution of unequal competitors. In: Sibley RM, Smith RH (eds) Behavioural ecology: ecological consequences of adaptive behaviour. Blackwell, Oxford, pp 255–274Google Scholar
  66. Swain DP, Wade EJ (1993) Density-dependent geographic distribution of Atlantic cod (Gadus morhua) in the southern gulf of St. Lawrence. Can J Fish Aquat Sci 50:725–733Google Scholar
  67. Thompson FR III, Robinson SK, Donovan TM, Faaborg J, Whitehead DR (2000) Biogeographic, landscape, and local factors affecting cowbird abundance and host parasitism levels. In: Smith JNM, Cook TL, Rothstein SI, Robinson SK, Sealy SG (eds) Ecology and management of cowbirds and their hosts. University of Texas Press, Austin, pp 271–279Google Scholar
  68. Tregenza T (1995) Building on the ideal free distribution. Adv Ecol Res 26:253–307Google Scholar
  69. Trine CL (2000) Effects of multiple parasitism on cowbird and wood thrush nesting success. In: Smith JNM, Cook TL, Rothstein SI, Robinson SK, Sealy SG (eds) Ecology and management of cowbirds and their hosts. University of Texas Press, Austin, pp 135–144Google Scholar
  70. Valladares G, Lawton JH (1991) Host-plant selection in the holly leaf-miner: does mother know best? J Anim Ecol 60:227–240Google Scholar
  71. Vogl W, Taborsky M, Taborsky B, Teuschl Y, Honza M (2002) Cuckoo females preferentially use specific habitats when searching for host nests. Anim Behav 64:843–850CrossRefGoogle Scholar
  72. Winslow DE (1999) Mechanistic approaches to the investigations of edge effects on avian productivity. Curr Ornithol 15:262–309Google Scholar
  73. Winter M (1999) Nesting biology of dickcissels and Henslow’s sparrows in southwestern Missouri prairie fragments. Wilson Bull 111:515–527Google Scholar
  74. Winter M, Johnson DH, Faaborg J (2000) Evidence for edge effects on multiple levels in tallgrass prairie. Condor 102:256–266Google Scholar
  75. Woolfenden BE, Gibbs HL, Sealy SG, McMaster DG (2003) Host use and fecundity of individual female brown-headed cowbirds. Anim Behav 66:95–106CrossRefGoogle Scholar
  76. Zimmerman JL (1983) Cowbird parasitism of dickcissels in different habitats and at different nest densities. Wilson Bull 95:7–22Google Scholar
  77. Zimmerman JL (1993) The birds of Konza: the avian ecology of the tallgrass prairie. University Press of Kansas, LawrenceGoogle Scholar

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  1. 1.United States Geological Survey, Kansas Cooperative Fish and Wildlife Research Unit, Division of BiologyKansas State UniversityManhattanUSA
  2. 2.Division of BiologyKansas State UniversityManhattanUSA

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