Importance of intraspecifically gregarious species in a tropical bird community


In both single- and mixed-species social groups, certain participants are known to play important roles in providing benefits. Identifying these participants is critical for understanding group dynamics, but is often difficult with large roving social groups in the wild. Here, we develop a new approach to characterize roles in social groups and apply it to mixed-species bird flocks (flocks hereafter) in an Indian tropical evergreen forest. Two types of species, namely intraspecifically gregarious and sallying species, are thought to play important roles in flocks because studies have shown they attract other flock participants. However, it is unclear why these types are attractive and whether they are essential for flock formation. We address these questions by focusing on the composition of the subset of flocks containing only two species each. In two-species flocks, it is reasonable to assume that at least one species obtains some kind of benefit. Therefore, only those species combinations that result in benefit to at least one species should occur as two-species flocks. Using data from 540 flocks overall, of which 158 were two-species flocks, we find that intraspecifically gregarious species are disproportionately represented in two-species flocks and always lead flocks when present, and that flocks containing them are joined significantly more by other species. Our results suggest that intraspecifically gregarious species are likely to be the primary benefit providers in flocks and are important for tropical flock formation. Our study also provides a new approach to understanding importance in other mixed-species and single-species social groups.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2


  1. Ali S, Ripley SD (1987) Compact handbook of the birds of India and Pakistan, together with those of Bangladesh, Nepal, Bhutan and Sri Lanka, 2nd edn. Oxford University Press, New Delhi

    Google Scholar 

  2. Aureli F, Schaffner CM, Boesch C, Bearder SK, Call J, Chapman CA, Connor R, Di Fiore A, Robin IM, Dunbar S, Henzi P, Holekamp K, Korstjens AH, Layton R, Lee P, Lehmann J, Manson JH, Ramos-Fernandez G, Strier KB, van Schaik CP (2008) Fission-fusion dynamics. Curr Anthropol 49:627–654. doi:10.1086/667653

    Article  Google Scholar 

  3. Bell HL (1983) A bird community of lowland rain forest in New Guinea. 5. Mixed species feeding flocks. Emu 82:265–275. doi:10.1071/MU9820256s

    Google Scholar 

  4. Couzin ID, Krause J, Franks NA, Levin SA (2005) Effective leadership and decision-making in animal groups on the move. Nature 433:513–516

    PubMed  Article  CAS  Google Scholar 

  5. Diamond J (1987) Flocks of brown and black New Guinea birds: a bicoloured mixed-species foraging association. Emu 87:201–211. doi:10.1071/MU9870201

    Article  Google Scholar 

  6. Dolby AS, Grubb TC Jr (1998) Benefits to satellite members in mixed-species foraging groups: an experimental analysis. Anim Behav 56:501–509

    PubMed  Article  Google Scholar 

  7. Dolby AS, Grubb TC Jr (1999) Functional roles in mixed-species flocks: a field manipulation. Auk 116:557–559

    Article  Google Scholar 

  8. Flower T (2010) Fork-tailed drongos use deceptive mimicked alarm calls to steal food. Proc R Soc Lond B. doi:10.1098/rspb.2010.1932

  9. French AR, Smith TB (2005) Importance of body size in determining dominance hierarchies among tropical frugivores. Biotropica 37:96–101. doi:10.1111/j.1744-7429.2005.04051.x

    Article  Google Scholar 

  10. Goodale E, Beauchamp G (2010) The relationship between leadership and gregariousness in mixed-species bird flocks. J Avian Biol 41:1–5. doi:10.1111/j.1600-048X.2009.04828.x

    Article  Google Scholar 

  11. Goodale E, Kotagama SW (2005a) Testing the roles of species in mixed-species bird flocks of a Sri Lankan rainforest. J Trop Ecol 21:669–676. doi:10.1017/S0266467405002609

  12. Goodale E, Kotagama SW (2005b) Alarm calling in Sri Lankan mixed-species bird flocks. Auk 122:108–120

    Article  Google Scholar 

  13. Goodale E, Nizam BZ, Robin VV, Sridhar H, Trivedi P, Kotagama SW, Padmalal UKGK, Perera R, Pramod P, Vijayan L (2009) Regional variation in the composition and structure of of mixed-species bird flocks in the Western Ghats and Sri Lanka. Curr Sci 97:648–663

    Google Scholar 

  14. Greenberg R (2000) Birds of many feathers: the formation and structure of mixed-species flocks of forest birds. In: Boinski S, Gerber PA (eds) On the move: how and why animals travel in groups. University of Chicago Press, Chicago, pp 521–559. doi:

  15. Harrison NM, Whitehouse MJ (2011) Mixed-species flocks: an example of niche construction? Anim Behav 81:675–683. doi:10.1016/j.anbehav.2011.01.013

  16. Hart PJ, Freed LA (2003) Structure and dynamics of mixed-species flocks in a Hawaiian rain forest. Auk 120:82–95

    Article  Google Scholar 

  17. Hino T (1998) Mutualistic and commensal organization of avian mixed-species foraging flocks in a forest of western Madagascar. J Avian Biol 29:17–24

    Article  Google Scholar 

  18. Hutto RL (1994) The composition and social organization of mixed-species flocks in a tropical deciduous forest in western Mexico. Condor 96:105–118

    Article  Google Scholar 

  19. Jullien M, Clobert J (2000) The survival value of flocking in neotropical birds: reality or fiction? Ecology 81:3416–3430. doi:10.1890/0012-9658(2000)081[3416:TSVOFI]2.0.CO;2

  20. Jullien M, Thiollay J-M (1998) Multi-species territoriality and dynamics of neotropical understory bird flocks. J Anim Ecol 67:227–252. doi:10.1046/j.1365-2656.1998.00171.x

    Article  Google Scholar 

  21. Kéfi S, Berlow EL, Wieters EA, Navarette SA, Petchey OL, Wood SA, Boit A, Joppa LN, Lafferty KD, Williams RJ, Martinez ND, Menge BA, Blanchette CA, Iles AC, Brose U (2012) More than a meal… integrating non-feeding interactions into food webs. Ecol Lett 15:291–300. doi:10.1111/j.1461-0248.2011.01732.x

    Article  Google Scholar 

  22. King DI, Rappole JH (2001) Kleptoparasitism of laughingthrushes Garrulax by Greater racket-tailed drongos Dicrurus paradiseus in Myanmar. Forktail 17:121–122

    Google Scholar 

  23. Kotagama SW, Goodale E (2004) The composition and spatial organization of mixed-species flocks in a Sri Lankan rainforest. Forktail 20:63–70

    Google Scholar 

  24. Maldonado-Coelho M, Marini MÂ (2004) Mixed-species bird flocks from Brazilian Atlantic forest: the effects of forest fragmentation and seasonality on their size, richness and stability. Biol Conserv. doi:10.1016/S0006-3207(03)00169-1

  25. McLean IG (1984) Feeding association between fantails and saddlebacks: who benefits? NZ J Ecol 7:165–168

    Google Scholar 

  26. Morse DH (1970) Ecological aspects of some mixed-species foraging flocks of birds. Ecol Monogr 40:119–168. doi:10.2307/1942443

  27. Moynihan M (1962) The organization and probable evolution of some mixed-species flocks of Neotropical birds. Smithson Misc Coll 143:1–140

    Google Scholar 

  28. Munn CA (1986) Birds that cry ‘wolf’. Nature 391:143–145. doi:10.1038/319143a0

    Article  Google Scholar 

  29. Nijman V (2004) Seasonal variation in naturally occurring mobbing behaviour of drongos (Dicruridae) towards two avian predators. Ethol Ecol Evol 16:25–32

    Article  Google Scholar 

  30. Remsen JV Jr, Robinson SK (1990) A classification scheme for birds in terrestrial foraging habitats. Stud Avian Biol 13:144–160

    Google Scholar 

  31. Satischandra SHK, Kudavidanage EP, Kotagama SW, Goodale E (2007) The benefits of joining mixed-species flocks for greater racket-tailed drongos Dicrurus paradiseus. Forktail 23:145–148

    Google Scholar 

  32. Sazima C, Krajewski JP, Bonaldo RM, Sazima I (2007) Nuclear-follower foraging associations of reef fishes and other animals at an oceanic archipelago. Environ Biol Fish 80:351–361

  33. Sridhar H, Shanker K (2014) Using intra-flock association patterns to understand why birds participate in mixed-species foraging flocks in terrestrial habitats. Behav Ecol Sociobiol 68:185–196. doi:10.1007/s00265-013-1633-3

    Article  Google Scholar 

  34. Sridhar H, Beauchamp G, Shanker K (2009) Why do birds participate in mixed-species foraging flocks? Anim Behav 78:337–347. doi:10.1016/j.anbehav.2009.05.008

  35. Sridhar H, Jordán F, Shanker K (2013) Species importance in a heterospecific foraging association network. Oikos 122:1325–1334. doi:10.1111/j.1600-0706.2013.00101.x

    Article  Google Scholar 

  36. Srinivasan U, Quader S (2012) To eat and not be eaten: modeling resources and safety in multi-species animal groups. PLoS ONE 7:e42071. doi:10.1371/journal.pone.0042071

    PubMed  Article  CAS  PubMed Central  Google Scholar 

  37. Srinivasan U, Raza R, Quader S (2010) The nuclear question: rethinking species importance in multi-species animal groups. J Anim Ecol 79:948–954. doi:10.1111/j.1365-2656.2010.01707.x

    PubMed  Article  Google Scholar 

  38. Stensland E, Angerbjörn A, Berggren P (2003) Mixed species groups in mammals. Mammal Rev 33:205–223. doi:10.1046/j.1365-2907.2003.00022.x

    Article  Google Scholar 

  39. Stotz DF (1993) Geographic variation in species composition of mixed species flocks in lowland humid forests in Brazil. Pap Avul Zool 38:61–75

    Google Scholar 

  40. Stouffer PC, Bierregaard Jr RO (1995) Use of Amazonian forest fragments by understory insectivorous birds. Ecology 76:2429–2445. doi:10.2307/2265818

  41. Styring AR, Ickes K (2001) Interactions between the greater racket-tailed drongo and woodpeckers in a lowland Malaysian rainforest. Forktail 17:119–120

    Google Scholar 

  42. Székely T, Szép T, Zuhas T (1989) Mixed-species flocking of tits (Parus spp.): a field experiment. Oecologia 78:490–495. doi:10.1007/BF00378739

    Article  Google Scholar 

  43. Veena T, Lokesha R (1993) Association of drongos with myna flocks: are drongos benefited? J Biosci 18:111–119

    Article  Google Scholar 

  44. Williams R, Lusseau D (2006) A killer whale social network is vulnerable to targeted removals. Biol Lett 2:497–500

    PubMed  Article  PubMed Central  Google Scholar 

Download references


We thank the Ministry of Environment and Forests, Government of India and International Foundation for Science (Grant no. D/4910-1) for supporting this study and the Karnataka forest department for providing permits for field work. We thank Eben Goodale, Rajah Jayapal and Kathryn Sieving for commenting on a draft of this paper. H.S. thanks Prakash, Nagesh, Narayan, Chandrakant and Sadanand for help with fieldwork. This paper was completed when H.S. was a fellow of the Wissenschaftskolleg zu Berlin.

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical standard

This study complies with the current laws of India, where the study was carried out.

Author information



Corresponding author

Correspondence to Hari Sridhar.

Additional information

Communicated by Toni Laaksonen.

Electronic supplementary material

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Sridhar, H., Shanker, K. Importance of intraspecifically gregarious species in a tropical bird community. Oecologia 176, 763–770 (2014).

Download citation


  • Animal sociality
  • Facilitation
  • Leadership
  • Mixed-species flocks
  • Species importance