Behavioral Ecology and Sociobiology

, Volume 65, Issue 4, pp 823–835 | Cite as

Seasonal migrations of black bears (Ursus americanus): causes and consequences

  • Karen V. NoyceEmail author
  • David L. Garshelis
Original Paper


American black bears frequently abandon their home ranges in late summer and move to feeding areas to fatten themselves for hibernation. We examined seasonal movements of 206 radio-collared bears in north-central Minnesota during 1981–1990. We exploited the variability in this long-term data set to test tradeoffs for animals leaving their home range. Late summer movements were common for both sexes and all ages (39% of females, 44% of males), but were variable from year-to-year in prevalence, timing, and destination. Bears typically left their summer home ranges in August and returned ~6 weeks later in September or October. Most traveled southward, where acorns were more plentiful (median = 10 km for females, 26 km for males; maximum = 168 km). These facultative migrations were most common when rich resources were available outside home ranges. Bears were least apt to leave when foods were scarce in their home range, possibly sensing a risk of migrating during a widespread food failure. Among females, those whose body mass was close to a reproductive threshold were most prone to migrate. Migrating bears were less likely to be killed by hunters, suggesting that they were especially vigilant.


Cost/benefit trade-offs Food abundance Hunting mortality Oak mast Reproductive threshold Seasonal movements 



This project was initiated and supported by the Minnesota Department of Natural Resources as part of a long-term research project on the population dynamics of black bears in Minnesota. We are grateful for the assistance of many DNR biologists, foresters, and other personnel, as well as the pilots, student interns and volunteers who assisted with radio-telemetry, trapping and handling bears, conducting food surveys, and maintaining records. In particular, we thank P. Coy, P. Harris, J. Young, D. Clapp, B. Sampson, K. Soring, M. Gallagher, and T. Lizotte. K. Kerr and G. Matson sectioned teeth for age determination. We thank J. Fieberg for statistical advice and E. Hellgren for helpful comments on the manuscript.


  1. Alerstam T, Hedenström A, Åkesson S (2003) Long-distance migration: evolution and determinants. Oikos 103:247–260CrossRefGoogle Scholar
  2. Amstrup SC, Beecham JJ (1976) Activity patterns of radio-collared black bears in Idaho. J Wildl Manage 40:340–348CrossRefGoogle Scholar
  3. Arnold TW (2010) Uninformative parameters and model selection using Akaike’s information criterion. J Wildl Manage 74:1175–1178CrossRefGoogle Scholar
  4. Beck, TDI (1991) Black bears of west-central Colorado. Colorado Div Wildl Tech Pub No 39Google Scholar
  5. Brönmark C, Skov C, Brodersen J, Nilsson PA, Hansson L (2008) Seasonal migration determined by a trade-off between predator avoidance and growth. PLoS ONE 3:e1957. doi: 10.1371/journal.pone.0001957 PubMedCrossRefGoogle Scholar
  6. Brown JS, Alkon PU (1990) Testing values of crested porcupine habitats by experimental food patches. Oecologia 83:512–518CrossRefGoogle Scholar
  7. Brown JS, Laundré JW, Gurung M (1999) The ecology of fear: optimal foraging, game theory, and trophic interactions. J Mammal 80:385–399CrossRefGoogle Scholar
  8. Costello C, Creel SR, Kalinowski ST, Vu NV, Quigley HB (2009) Determinants of male reproductive success in American black bears. Behav Ecol Sociobiol 64:125–134CrossRefGoogle Scholar
  9. Coy PC, Garshelis DG (1992) Reconstructing reproductive histories of black bears from incremental layering in dental cementum. Can J Zool 70:2150–2160CrossRefGoogle Scholar
  10. Dingemanse NJ, Réale D (2005) Natural selection and animal personality. Behav 142:1165–1190CrossRefGoogle Scholar
  11. Dingle H (1996) Migration: the biology of life on the move. Oxford University Press, CambridgeGoogle Scholar
  12. Dingle H, Drake VA (2007) What is migration? BioSci 57:113–121CrossRefGoogle Scholar
  13. Elowe KD, Dodge WE (1989) Factors affecting black bear reproductive success and cub survival. J Wildl Manage 53:962–968CrossRefGoogle Scholar
  14. Fox AD, Kobro S, Lehikoinen A, Lyngs P, Vaisanen R (2009) Northern bullfinch Pyrrhula p pyrrhula irruptive behavior linked to rowanberry Sorbus aucuparia abundance. Ornis Fenn 86:51–60Google Scholar
  15. Garshelis DL (1994) Density-dependent population regulation of black bears. In: Taylor M (ed) Density-dependent population regulation of black, brown, and polar bears. Int Conf Bear Res Manage Monog Ser 3. pp 3–14Google Scholar
  16. Garshelis DL, Noyce KV (2008) Seeing the world through the nose of a bear—diversity of foods fosters behavioral and demographic stability. In: Fulbright TE, Hewitt DG (eds) Wildlife science: linking ecological theory and management applications. CRC Press, Boca RatonGoogle Scholar
  17. Garshelis DL, Pelton MR (1980) Activity of black bears in the Great Smoky Mountains National Park. J Mammal 61:8–19CrossRefGoogle Scholar
  18. Garshelis DL, Pelton MR (1981) Movements of black bears in the Great Smoky Mountains National Park. J Wildl Manage 45:912–925CrossRefGoogle Scholar
  19. Hashimoto Y, Yasutake A (1999) Seasonal changes in body weight of female Asiatic black bears under captivity. Mamm Study 24:1–6CrossRefGoogle Scholar
  20. Hellgren EC, Vaughan MR (1990) Range dynamics of black bears in Great Dismal Swamp, Virginia-North Carolina. Proc Annual Conf SE Assoc Fish Wildl Agencies 44:268–278Google Scholar
  21. Hellgren EC, Onorato DP, Skiles JR (2005) Dynamics of a black bear population within a desert metapopulation. Biol Conserv 122:131–140CrossRefGoogle Scholar
  22. Hilderbrand GV, Jenkins SG, Schwartz CC, Hanley TA, Robbins CT (1999) Effect of seasonal differences in dietary meat intake on changes in body mass and composition in wild and captive brown bears. Can J Zool 77:1623–1630CrossRefGoogle Scholar
  23. Inman RM, Pelton MR (2002) Energetic production by soft and hard mast foods of American black bears in the Smoky Mountains. Ursus 13:57–68Google Scholar
  24. John AWG, Roskell J (1985) Jay movements in autumn 1983. Br Birds 78:611–637Google Scholar
  25. Kaitala A, Kaitala V, Lundberg P (1993) A theory of partial migration. Am Nat 142:59–81CrossRefGoogle Scholar
  26. Kasbohm JW, Vaughan MR, Kraus JG (1998) Black bear home range dynamics and movement patterns during a gypsy moth infestation. Ursus 10:259–267Google Scholar
  27. Kenney RD, Mayo CA, Winn HE (2001) Migration and foraging strategies at varying spatial scales in western North Atlantic right whales: a review of hypotheses. J Cetacean Res Manage spec issue 2:251–260Google Scholar
  28. Kirkpatrick RL, Pekins PJ (2002) Nutritional value of acorns for wildlife. In: McShea WJ, Healy WM (eds) Oak forest ecosystems: ecology and management for wildlife. Johns Hopkins University Press, Baltimore, pp 173–181Google Scholar
  29. Klenner W (1987) Seasonal movements and home range utilization patterns of the Black Bear, Ursus americanus, in western Manitoba. Can Field Nat 101:558–568Google Scholar
  30. Koenig WD, Knops JMH (2000) Patterns of annual seed production by northern hemisphere trees: a global perspective. Am Nat 155:59–69PubMedCrossRefGoogle Scholar
  31. Kohlmann SG, Risenhoover KL (1994) Spatial and behavioural response of white-tailed deer to forage depletion. Can J Zool 72:506–513CrossRefGoogle Scholar
  32. Kovach AI, Powell RA (2003) Effects of body size on male mating tactics and paternity in black bears, Ursus americanus. Can J Zool 81:1257–1268CrossRefGoogle Scholar
  33. Kudaktin AN, Chestin IE (1993) The Caucasus. In: Vaisfeld MA, Chestin IE (eds) Game animals of Russia and adjacent countries and their environment: bears. Nauka, Moscow, pp 136–169Google Scholar
  34. Landriault J, Hall MN, Hamr J, Mallory FF (2006) Long-range homing by an adult female black bear, Ursus americanus. Can Field Nat 120:57–60Google Scholar
  35. Lariviere S, Huot J, Samson C (1994) Daily activity patterns of female black bears in a northern mixed-forest environment. J Mammal 75:613–620CrossRefGoogle Scholar
  36. Lee DJ, Vaughan MR (2003) Dispersal movements by subadult American black bears in Virginia. Ursus 14:162–170Google Scholar
  37. McShea WJ, Schwede G (1993) Variable acorn crops: responses of white-tailed deer and other mast consumers. J Mammal 74:999–1006CrossRefGoogle Scholar
  38. Minnesota Department of Natural Resources (2003) Field guide to the native plant communities of Minnesota: the Laurentian mixed forest province. Ecological land classification program, Minnesota County Biological survey and Natural Heritage and Nongame Research Program. Minnesota Dept Nat Resources St. PaulGoogle Scholar
  39. Newton I (2006) Advances in the study of irruptive migration. Ardea 94:433–460Google Scholar
  40. Nicholson MC, Bowyer RT, Kie JG (1997) Habitat selection and survival of mule deer: tradeoffs associated with migration. J Mammal 789:483–504CrossRefGoogle Scholar
  41. Noyce KV, Coy PL (1990) Abundance and productivity of bear food species in different forest types of northcentral Minnesota. Int Conf Bear Res Manage 8:169–181Google Scholar
  42. Noyce KV, Garshelis DL (1994) Body size and blood characteristics as indicators of condition and reproductive performance in black bears. Int Conf Bear Res Manage 9:481–496Google Scholar
  43. Noyce KV, Garshelis DL (1997) Influence of natural food abundance on black bear harvests in Minnesota. J Wildl Manage 61:1067–1074CrossRefGoogle Scholar
  44. Noyce KV, Garshelis DL (1998) Spring weight changes in black bears in northcentral Minnesota: the negative foraging period revisited. Ursus 10:521–531Google Scholar
  45. Olsson IC, Greenberg LA, Bergman E, Wysujack K (2006) Environmentally induced migration: the importance of food. Ecol Lett 9:645–651PubMedCrossRefGoogle Scholar
  46. Pelton MR (1989) The impacts of oak mast on black bears in the southern Appalachians. In: McGee CH (ed) Proceedings of the workshop on Southern Appalachian mast management. University of Tennessee, Knoxville, pp 7–11Google Scholar
  47. Rogers LL (1987a) Effects of food supply and kinship on social behavior, movements, and population growth of black bears in northeastern Minnesota. Wildl Monog 97Google Scholar
  48. Rogers LL (1987b) Navigation by adult black bears. J Mammal 68:185–188CrossRefGoogle Scholar
  49. Rogers LL (1989) Home, sweet-smelling home. Nat Hist 9(89):61–67Google Scholar
  50. Sabine DL, Morrison SF, Whitlaw HA, Ballard WB, Forbes GJ (2002) Migration behavior of white-tailed deer under varying winter climate regimes in New Brunswick. J Wildl Manage 66:718–728CrossRefGoogle Scholar
  51. Sæther BE, Andersen R (1990) Resource limitation in a generalist herbivore, the moose Alces alces: ecological constraints on behavioural decisions. Can J Zool 68:993–999CrossRefGoogle Scholar
  52. Samson C, Huot J (1998) Movements of female black bears in relation to landscape vegetation type in southern Quebec. J Wildl Manage 62:718–727CrossRefGoogle Scholar
  53. Sauer PR, Free SL, Browne SD (1969) Movement of tagged black bears in the Adirondacks. NY Fish Game J 16:205–223Google Scholar
  54. Schooley RL, McLaughlin CR, Krohn WB, Matula GJ (1994) Spatiotemporal patterns of macrohabitat use by female black bears during fall. Int Conf Bear Res Manage 9:339–348Google Scholar
  55. Schorger AW (1946) Influx of bears into St. Louis County, Minnesota. J Mammal 27:177Google Scholar
  56. Schwartz CC, Franzmann AW (1991) Interrelationship of black bears to moose and forest succession in the northern coniferous forest. Wildl Monog 113Google Scholar
  57. Schwartz CC, Franzmann AW (1992) Dispersal and survival of subadult black bears from the Kenai Peninsula, Alaska. J Wildl Manage 56:426–431CrossRefGoogle Scholar
  58. Symonds MRE, Moussalli A (2010) A brief guide to model selection, multimodal inference, and model averaging in behavioural ecology using Akaike’s information criterion. Behav Ecol Sociobiol. doi: 10.1007/s00265-010-1037-6 Google Scholar
  59. Vaughan M (2002) Oak trees, acorns, and bears. In: McShea WJ, Healy WM (eds) Oak forest ecosystems: ecology and management for wildlife. The Johns Hopkins University Press, Baltimore, pp 224–240Google Scholar
  60. Welch CA, Keay J, Kendall KC, Robbins CT (1997) Constraints on frugivory by bears. Ecology 78:1105–1119CrossRefGoogle Scholar
  61. White PJ, Davis TL, Barnowe-Meyer KK, Crabtree RL, Garrott RA (2007) Partial migration and philopatry of Yellowstone pronghorn. Biol Conserv 135:502–510CrossRefGoogle Scholar
  62. Whitehead CJ (1969) Oak mast yields on wildlife management areas in Tennessee. Tennessee Game and Fish Commission, NashvilleGoogle Scholar
  63. Willey CH (1974) Aging black bears from first premolar tooth sections. J Wildl Manage 38:97–100CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  1. 1.Minnesota Department of Natural ResourcesForest Wildlife Populations and Research GroupGrand RapidsUSA

Personalised recommendations