Advertisement

Oecologia

, Volume 74, Issue 2, pp 277–285 | Cite as

Dietary shifts, niche relationships and reproductive output of coexisting Kestrels and Long-eared Owls

  • E. Korpimäki
Original Papers

Summary

Food samples of breeding Kestrels (Falco tinnunculus) and Long-eared Owls (Asio otus) were collected in the peak and low phase of their preferred prey (Microtus voles) in western Finland. Diets of pairs that bred as neighbours (≤1 km) with interspecifics were compared with those of non-neighbours. In both species, neighbouring pairs fed less on Microtus voles and more on alternative prey than did non-neighbours. Competition theory predicts that diet overlap should be lower during prey shortage and that diet similarity should be especially reduced in neighbouring pairs. Observations were consistent with expectations: diet similarity was lower in the low vole years and neighbouring pairs showed less diet overlap that non-neighbours. Differences in habitat composition and prey availability at the sample sites should not confuse the results. In addition to the high diet similarity, hunting habitats and nest sites of the species overlapped almost completely; they only showed clear temporal segregation in hunting. Probably because of food competition, the neighbouring pairs of both species produced significantly fewer young than the non-neighbours. These results contrast with the view that the diet composition and dietary shift of rodent-feeding predatory birds can be interpreted in terms of simple opportunistic foraging. In the breeding season, interspecific competition for food seems to be an important factor that affects the niches of these species, especially in northern areas, where the seasonal low phase of voles in spring and the number of alternative prey are lower than in more southern areas.

Key words

Diet breadth Overlap Competition Kestrel Long-eared Owl 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Abrams P (1983) The theory of limiting similarity. Ann Rev Ecol Syst 14:359–376Google Scholar
  2. Alatalo RV (1981) Competition in tits Parus spp. and the Goldcrest Regulus regulus: foraging shifts in multispecific flocks. Oikos 37:335–344Google Scholar
  3. Alatalo RV, Gustafsson K, Lundberg A, Ulfstrand S (1985) Habitat shift of the Willow Tit Parus montanus in the absence of the Marsh Tit Parus palustris. Ornis Scand 16:121–128Google Scholar
  4. Avery RA (1971) Estimates of food consumption by the lizard Lacerta vivipara Jacquin. J Anim Ecol 40:351–366Google Scholar
  5. Beusekom CF van (1972) Ecological isolation with respects to food between Sparrowhawk and Goshawk. Ardea 60:72–96Google Scholar
  6. Carothers JH, Jaksié FM (1984) Time as a niche difference: the role of interference competition. Oikos 42:403–406Google Scholar
  7. Charnov EL, Orians GH, Hyatt K (1976) Ecological implications of resource depression. Am Nat 110:247–259Google Scholar
  8. Cody ML (1974) Competition and the structure of bird communities. Princeton University Press, PrincetonGoogle Scholar
  9. Colwell RK, Futuyma DJ (1971) On the measurement of niche breadth and overlap. Ecology 52:567–576Google Scholar
  10. Connell JH (1983) On the prevalence and relative importance of interspecific competition: evidence from field experiments. Am Nat 122:661–696Google Scholar
  11. Craighead JJ, Craighead FC (1969) Hawks, owls and wildlife. Dover Publ, New York, 2nd EditionGoogle Scholar
  12. Diamond JM (1978) Niche shifts and the rediscovery of interspecific competition. Am Sci 66:322–331Google Scholar
  13. Emlen JM (1966) The role of time and energy in food preference. Am Nat 100:611–617Google Scholar
  14. Erlinge S, Göransson G, Högstedt G, Liberg O, Loman J, Nilsson I, Nilsson T, von Schantz T, Sylvén M (1982) Factors limiting numbers of vertebrate predators in a predator prey community. Trans Intern Congr Game Biol 14:261–268Google Scholar
  15. Forsman D (1984) Rovfagelsguiden. Lintutieto, HelsinkiGoogle Scholar
  16. Glutz von Blotzheim UN, Bauer KM (1980) Handbuch der Vögel Mitteleuropas. Band 9. Akademische Verlagsgesellschaft; WiesbadenGoogle Scholar
  17. Greene HW, Jaksié FM (1983) Food-niche relationships among sympatric predators: effects of level of prey identification. Oikos 40:151–154Google Scholar
  18. Grossman ML, Hamlet J (1964) Birds of Prey of the World. Bonanza Books, New YorkGoogle Scholar
  19. Gustafsson L (1985) Fitness factors in the Collared Flycatcher Ficedula albicollis Temm. Ph D thesis, Dept Zool, Univ Uppsala, SwedenGoogle Scholar
  20. Haartman L von, Hildén O, Linkola P, Suomalainen P, Tenovuo R (1963–72) Pohjolan linnut värikuvin. Otava, HelsinkiGoogle Scholar
  21. Hairston NG, Smith FE, Slobodkin LB (1960) Community structure, population control, and competition. Am Nat 94:421–425Google Scholar
  22. Herrera CM, Hiraldo F (1976) Food-niche and trophic relationships among European owls. Ornis Scand 7:29–41Google Scholar
  23. Huey RP, Pianka ER, Egan ME, Coons LW (1974) Ecological shifts in sympatry: Kalahari fossorial lizards (Typhlosaurus). Ecology 55:304–316Google Scholar
  24. Hutchinson GE (1957) Concluding remarks. Cold Spring Harbor Symp Quant Biol 22:415–427Google Scholar
  25. Högstedt G (1980) Prediction and test of the effects of interspecific competition. Nature 283:64–66Google Scholar
  26. Hämies J, Korpimäki E (1987) Insect food of the Kestrel, Falco tinnunculus, during breeding in western Finland. Aquilo Ser Zool 25 (in press)Google Scholar
  27. Järvinen O (1977) A methodological note on the measurement of the diet specialization of predators. Ornis Fenn 54:90–91Google Scholar
  28. Jaksić FM (1982) Inadequacy of activity time as a niche difference: the case of diurnal and nocturnal raptors. Oecologia (Berl) 52:171–175Google Scholar
  29. Jaksié FM, Braker HE (1983) Food-niche relationships and guild structure of diurnal birds of prey: competition versus opportunism. Can J Zool 61:2230–2241Google Scholar
  30. Korpimäki E (1981) On the ecology and biology of Tengmalm's Owl (Aegolius funereurs) in Southern Ostrobothnia and Suomenselkä, western Finland. Acta Univ Oul A 118 Biol 13:1–84Google Scholar
  31. Korpimäki E (1982) Zur Aktivität des Stars (Sturnus vulgaris) in Süd-österbotten, Finnland, während der Nistzeit. Beitr Vogelkd (Jena) 28:129–138Google Scholar
  32. Korpimäki E (1983) Tuulihaukkapönttökokeilun tuloksia. Lintumies 18:132–137Google Scholar
  33. Korpimäki E (1984a) Population dynamics of birds of prey in relation to fluctuations in small mammal populations in western Finland. Ann Zool Fennici 21:287–293Google Scholar
  34. Korpimäki E (1984b) Food piracy between European Kestrel and Short-eared Owl. Raptor Res 18:113–115Google Scholar
  35. Korpimäki E (1985a) Prey choice strategies of the Kestrel Falco tinnunculus in relation to available small mammals and other finnish birds of prey. Ann Zool Fennici 22:91–104Google Scholar
  36. Korpimäki E (1985b) Rapid tracking of microtine populations by their avian predators: possible evidence for stabilizing predation. Oikos 45:281–284Google Scholar
  37. Korpimäki E (1985c) Diet of the Kestrel Falco tinnunculus in the breeding season. Ornis Fenn 62:130–137Google Scholar
  38. Korpimäki E (1986) Predation causing synchronous decline phases in microtine and shrew populations in western Finland. Oikos 46:124–127Google Scholar
  39. Korpimäki E (1987) Timing of breeding of Tengmalm's Owl Aegolius funereus in relation to vole dynamics in western Finland. Ibis 129:58–68Google Scholar
  40. Korpimäki E, Haapoja R, Ikola S (1979) Two nests of the Kestrel close to each other. Lintumies 14:35Google Scholar
  41. Korpimäki E, Huhtala K (1986) Nest visit frequencies and activity patterns of Ural Owls Strix uralensis. Ornis Fenn 63:42–46Google Scholar
  42. Lack D (1946) Competition for food by birds of prey. J Anim Ecol 15:123–129Google Scholar
  43. Lawlor LR (1980) Overlap, similarity, and competition coefficients. Ecology 61:245–251Google Scholar
  44. Levins R (1968) Evolution in changing environments. Princeton Univ Press, PrincetonGoogle Scholar
  45. Lundberg A (1979) Residency, migration and a compromise: adaptations to nest-site scarcity and food specialization in three Fennoscandian owl species. Oecologia (Berlin) 41:273–281Google Scholar
  46. MacArthur RH, Levins R (1967) The limiting similarity, convergence, and divergence of coexisting species. Am Nat 101:377–385Google Scholar
  47. Marks JS, Marti CD (1984) Feeding ecology of sympatric Barn Owls and Long-eared Owls in Idaho. Ornis Scand 15:135–143Google Scholar
  48. May RM (1975) Some notes on measuring the competition matrix, α. Ecology 56:737–741Google Scholar
  49. Menge BA, Sutherland JP (1976) Species diversity gradients: synthesis of the roles of predation, competition, and temporal heterogeneity. Am Nat 110:351–369Google Scholar
  50. Mikkola H (1983) Owls of Europe. T & AD Poyser, CaltonGoogle Scholar
  51. Minot EO (1981) Effects of interspecific competition for food in breeding Blue and Great Tits. J Anim Ecol 50:375–385Google Scholar
  52. Newton I (1979) Population ecology of raptors. T & AD Poyser, BerkhamstedGoogle Scholar
  53. Nilsson IN (1984) Prey weight, food overlap, and reproductive output of potentially competing Long-eared and Tawny Owls. Ornis Scand 15:176–182Google Scholar
  54. Opdam P (1975) Inter- and intraspecific differentiation with respect to feeding ecology in two sympatric species of the genus Accipiter. Ardea 63:30–54Google Scholar
  55. Pianka ER (1973) The structure of lizard communities. Ann Rev Ecol Syst 4:53–74Google Scholar
  56. Piechocki R (1982) Der Turmfalke. Die Neue Brehm-Bücherie, A Ziemsen Verlag, Wittenberg Lutherstadt, 6.ed.Google Scholar
  57. Pyke GH, Pulliam HR, Charnov EL (1977) Optimal foraging: a selective review of theory and tests. Quart Rev Biol 52:137–154Google Scholar
  58. Reynolds RT, Meslow EC (1984) Partitioning of food and niche characteristics of coexisting Accipiter during breeding. Auk 101:761–779Google Scholar
  59. Schmitt RJ, Coyer JA (1983) Variation in surfperch diets between allopatry and sympatry: circumstancial evidence for competition. Oecologia (Berlin) 58:402–410Google Scholar
  60. Schmutz JK, Schmutz SM, Boag DA (1980) Coexistence of three species of hawks (Buteo spp) in the prairie-parkland ecotone. Can J Zool 58:1075–1089Google Scholar
  61. Schoener TW (1971) Theory of feeding strategies. Ann Rev Ecol Syst 2:369–404Google Scholar
  62. Schoener TW (1974) The compression hypothesis and temporal resource partitioning. Proc Natl Acad Sci US A 71:4169–4172Google Scholar
  63. Schoener TW (1975) Presence and absence of habitat shift in some widespread lizard species. Ecol Monogr 45:233–258Google Scholar
  64. Schoener TW (1982) The controversy over interspecific competition. Am Sci 70:586–590Google Scholar
  65. Schoener TW (1983) Field experiments on interspecific competition. Am Nat 122:240–285Google Scholar
  66. Schoener TW (1984) Size differences among sympatric, bird-eating hawks: a world-wide survey. In: Strong DR, Simberloff D, Abele LG, Thistle AB (eds). Ecological communities: conceptual issues and the evidence. Princeton University Press, Princeton, pp 254–281Google Scholar
  67. Schoener TW (1985) Some comments on Connell's and my reviews of field experiments on interspecific competition. Am Nat 125:730–740Google Scholar
  68. Sih A, Crowley P, McPeek M, Petranka J, Strohmeier K (1985) Predation, competition, and prey communities: a review of field experiments. Ann Rev Ecol Syst 16:269–311Google Scholar
  69. Siivonen L (1974) Pohjolan nisäkkäät. Otava, HelsinkiGoogle Scholar
  70. Simmons R (1986) Ecological segregation of the Red-Breasted Sparrowhawk Accipiter rufiventris and six coexisting accipitrine raptors in Southern Africa. Ardea 74:137–149Google Scholar
  71. Steenhof K, Kochert MN (1985) Dietary shifts of sympatric buteos during a prey decline. Oecologia (Berlin) 66:6–16Google Scholar
  72. Storer RW (1966) Sexual dimorphism and food habits in three North American accipiters. Auk 83:423–436Google Scholar
  73. Walter GH, Hulley PE, Craig AJFK (1984) Speciation, adaptation and interspecific competition. Oikos 43:246–248Google Scholar
  74. Wiens JA (1983) Interspecific competition. Am Sci 71:234–235Google Scholar
  75. Wiens JA, Rotenberry JT (1979) Diet niche relationships among North American grassland and shrubsteppe birds. Oecologia (Berlin) 42:253–292Google Scholar

Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • E. Korpimäki
    • 1
  1. 1.Department of ZoologyUniversity of OuluOuluFinland

Personalised recommendations