, Volume 139, Issue 2, pp 235–245 | Cite as

How do frugivores track resources? Insights from spatial analyses of bird foraging in a tropical forest

  • James F. SaraccoEmail author
  • Jaime A. Collazo
  • Martha J. Groom
Plant Animal Interactions


Frugivores often track ripe fruit abundance closely across local areas despite the ephemeral and typically patchy distributions of this resource. We use spatial auto- and cross-correlation analyses to quantify spatial patterns of fruit abundance and avian frugivory across a 4-month period within a forested 4.05-ha study grid in Puerto Rico. Analyses focused on two tanager species, Spindalis portoricensis and Nesospingus speculiferus, and their principal food plants. Three broad questions are addressed: (1) at what spatial scales is fruit abundance and frugivory patchy; (2) at what spatial scales do frugivores respond to fruit abundance; and (3) to what extent do spatial patterns of frugivory overlap between bird species? Fruit patch size, species composition, and heterogeneity was variable among months, despite fruit patch locations remaining relatively consistent between months. Positive correlations between frugivory and fruit abundance suggested tanagers successfully tracked fruit abundance. Frugivory was, however, more localized than fruit abundance. Scales of spatial overlap in frugivory and monthly variation in the foraging locations of the two tanager species suggested that interspecific facilitation may have been important in determining bird foraging locations. In particular, S. portoricensis, a specialist frugivore, may have relied on the loud calls of the gregarious generalist, N. speculiferus, to find new foraging areas. Such a mechanism could help explain the formation of mixed species feeding flocks and highlights the potential importance of facilitation between species that share resources.


Facilitation Frugivory Puerto Rico Spatial correlograms Tanagers 



We thank T. Carlo, H. Gamper, and C. Burney for assistance in the field. R. Moen, K. Pollock, T. Simons, J. Walters, T. Wentworth, and an anonymous reviewer provided comments that improved earlier versions of the manuscript. The study was funded by the Puerto Rico Department of Natural Resources, USGS Biological Resources Division, US Fish and Wildlife Service, and North Carolina State University.


  1. Birdsey, RA, Weaver, PM (1982) The forest resources of Puerto Rico. USDA Forest Service Resource Bulletin SO-85, Río Piedras, Puerto RicoGoogle Scholar
  2. Cruz A (1980) Avian feeding assemblages in Puerto Rico. Caribb J Sci 15:21–27Google Scholar
  3. Daily GC, Ehrlich PR (1994) Influence of social status on individual foraging and community structure in a bird guild. Oecologia 100:153–165Google Scholar
  4. Dowsett-Lemaire F (1996) Avian frugivore assemblages at three small-fruited tree species in the forests of northern Congo. Ostrich 67:88–89Google Scholar
  5. Ellingson AR, Andersen DC (2002) Spatial correlations of Diceroprocta apache and its host plants: evidence for a negative impact from Tamarix invasion. Ecol Entomol 27:16–24CrossRefGoogle Scholar
  6. Fauchald P, Erikstad KE, Skarsfjord H (2000) Scale-dependent predator-prey interactions: the hierarchical spatial distribution of seabirds and prey. Ecology 81:773–783Google Scholar
  7. Fleming TH (1979) Do tropical frugivores compete for food? Am Zool 19:1157–1172Google Scholar
  8. Giraldeau L-A (1984) Group foraging: the skill pool effect and frequency-dependent learning. Am Nat 124:72–79CrossRefGoogle Scholar
  9. Holdridge LR (1947) Determination of world plant formations from simple climatic data. Science 105:367–368Google Scholar
  10. Howe HF, Estabrook GF (1977) On intraspecific competition for avian dispersers in tropical trees. Am Nat 111:817–832CrossRefGoogle Scholar
  11. Hutto RL (1988) Foraging behavior patterns suggest a possible cost associated with participation in mixed-species bird flocks. Oikos 51:79–83Google Scholar
  12. Krebs JR (1973) Social learning and the significance of mixed-species flocks of chickadees. Can J Zool 51:1275–1288Google Scholar
  13. Krebs JR, MacRoberts MH, Cullen JM (1972) Flocking and feeding in the Great Tit, Parus major – an experimental study. Ibis 114:507–530Google Scholar
  14. Legendre P, Fortin M-J (1989) Spatial pattern and ecological analysis. Vegetatio 80:107–138Google Scholar
  15. Legendre P, Legendre L (1998) Numerical ecology, 2nd edn. Elsevier, AmsterdamGoogle Scholar
  16. Levey DJ (1988) Spatial and temporal variation in Costa Rican fruit and fruit-eating bird abundance. Ecol Monogr 58:251–269Google Scholar
  17. Liogier HA (1985) Descriptive flora of Puerto Rico and adjacent islands. Vol. 1: Casuarinaceae to Connaraceae. Editorial de la Universidad de Puerto Rico, Río Piedras, Puerto RicoGoogle Scholar
  18. Liogier HA, Martorell LF (2000) Flora of Puerto Rico and adjacent islands: a systematic synopsis, 2nd edn. Editorial de la Universidad de Puerto Rico, San Juan, Puerto RicoGoogle Scholar
  19. Loiselle BA, Blake JG (1993) Spatial distribution of understory fruit-eating birds and fruiting plants in a neotropical lowland wet forest Vegetatio 107/108:177–189Google Scholar
  20. Martin TE (1985) Resource selection by tropical frugivorous birds: integrating multiple interactions. Oecologia 66:563–573Google Scholar
  21. Miranda-Castro L, Puente-Rolón AR, and Vega-Castillo S (2000) First list of the vertebrates of Los Tres Picachos State Forest, Puerto Rico, with data on relative abundance and altitudinal distribution. Caribb J Sci 36:117–126Google Scholar
  22. Moran PAP (1950) Notes on continuous stochastic phenomena. Biometrika 37:17–23.Google Scholar
  23. Morisita M (1959) Measuring of interspecific association and similarity between communities. Mem Fac Sci Kyushu Univ Ser E 3:65–80Google Scholar
  24. Olupot W, Waser PM, Chapman CA (1998) Fruit finding by mangabeys (Lophocebus albigena): are monitoring of fig trees and use of sympatric frugivore calls possible strategies? Int J Primatol 19:339–353CrossRefGoogle Scholar
  25. Pérez-Rivera RA (1994) Feeding ecology of the Puerto Rican Bullfinch (Loxigilla portoricensis) in the Carite and Guánica Forests. Caribb J Sci 30:242–249Google Scholar
  26. Pratt TK (1984) Examples of tropical frugivores defending fruit-bearing plants. Condor 86:123–129Google Scholar
  27. Recher HF, Recher JT (1966) A contribution to the knowledge of the avifauna of the Sierra de Luquillo, Puerto Rico. Caribb J Sci 6:151–161Google Scholar
  28. Reich RM, Czaplewski RL, Bechtold WA (1994) Spatial cross-correlation of undisturbed, natural shortleaf pine stands in northern Georgia. Environ Ecol Stat 1:201–217Google Scholar
  29. Rey PJ (1995) Spatio-temporal variation in fruit and frugivorous bird abundance in olive orchards. Ecology 76:1625–1635Google Scholar
  30. Schaik CP van, Terborgh JW, Wright SJ (1993) The phenology of tropical forests: adaptive significance and consequences for primary consumers. Annu Rev Ecol Syst 24:353–377CrossRefGoogle Scholar
  31. Sokal RR (1979) Ecological parameters inferred from spatial correlograms. In Patil GP, Rosenzweig M (eds). Contemporary quantitative ecology and related ecometrics. International Co-operative Publishing, Fairland, Md., pp 167–196Google Scholar
  32. Terborgh J, Diamond JM (1970) Niche overlap in feeding assemblages of New Guinea birds. Wilson Bull 82:29–52Google Scholar
  33. Wartenberg D (1985) Multivariate spatial correlation: a method for exploratory geographical analysis. Geogr Anal 17:263–283Google Scholar
  34. Whetmore A (1916) Birds of Puerto Rico. U.S. Department of Agriculture Bulletin 326. U.S. Government Printing Office, Washington, D.C.Google Scholar
  35. Wiens JA (1989) Spatial scaling in ecology. Funct Ecol 3:385–397Google Scholar
  36. Willis EO (1966) Competitive exclusion and birds at fruiting trees in western Columbia. Auk 83:479–480Google Scholar
  37. Willis EO (1973) Local distribution of mixed flocks in Puerto Rico. Wilson Bull 85:75–77Google Scholar
  38. Willson MF, Whelan CJ (1990) The evolution of fruit color in fleshy-fruited plants. Am Nat 136:790–80CrossRefGoogle Scholar
  39. Winterbottom JM (1943) Mixed bird parties in the tropics, with special reference to northern Rhodesia. Auk 66:258–263Google Scholar

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • James F. Saracco
    • 1
    • 2
    Email author
  • Jaime A. Collazo
    • 1
  • Martha J. Groom
    • 1
    • 3
    • 4
  1. 1.North Carolina Cooperative Fish and Wildlife Research Unit, USGS Biological Resources Division, Department of ZoologyNorth Carolina State UniversityRaleighUSA
  2. 2.GustavusUSA
  3. 3.Interdisciplinary Arts and SciencesUniversity of WashingtonBothellUSA
  4. 4.Department of BiologyUniversity of WashingtonSeattleUSA

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