Flying in a flock comes at a cost in pigeons

Abstract

Flying birds often form flocks, with social1, navigational2 and anti-predator3 implications. Further, flying in a flock can result in aerodynamic benefits, thus reducing power requirements4, as demonstrated by a reduction in heart rate and wingbeat frequency in pelicans flying in a V-formation5. But how general is an aerodynamic power reduction due to group-flight? V-formation flocks are limited to moderately steady flight in relatively large birds, and may represent a special case. What are the aerodynamic consequences of flying in the more usual ‘cluster’6,7 flock? Here we use data from innovative back-mounted Global Positioning System (GPS) and 6-degrees-of-freedom inertial sensors to show that pigeons (1) maintain powered, banked turns like aircraft, imposing dorsal accelerations of up to 2g, effectively doubling body weight and quadrupling induced power requirements; (2) increase flap frequency with increases in all conventional aerodynamic power requirements; and (3) increase flap frequency when flying near, particularly behind, other birds. Therefore, unlike V-formation pelicans, pigeons do not gain an aerodynamic advantage from flying in a flock. Indeed, the increased flap frequency, whether due to direct aerodynamic interactions or requirements for increased stability or control, suggests a considerable energetic cost to flight in a tight cluster flock.

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Figure 1: Flap-number histogram contour plots.
Figure 2: Influence of speed, and power and flock factors on flap frequency and dorsal amplitude.
Figure 3: Relationship between flock factor and flap frequency or dorsal displacement.

References

  1. 1

    Nagy, M., Ákos, Z., Biro, D. & Vicsek, T. Hierarchical group dynamics in pigeon flocks. Nature 464, 890–893 (2010)

    ADS  CAS  Article  Google Scholar 

  2. 2

    Dell’Ariccia, G., Dell’Omo, G., Wolfer, D. P. & Lipp, H.-P. Flock flying improves pigeons’ homing: GPS track analysis of individual flyers versus small groups. Anim. Behav. 76, 1165–1172 (2008)

    Article  Google Scholar 

  3. 3

    Tinbergen, N. The Study of Instinct (Clarendon Press, 1951)

    Google Scholar 

  4. 4

    Lissaman, P. B. S. & Schollenberger, C. A. Formation flight of birds. Science 168, 1003–1005 (1970)

    ADS  CAS  Article  Google Scholar 

  5. 5

    Weimerskirch, H., Martin, J., Clerquin, Y., Alexandre, P. & Jiraskova, S. Energy saving in flight formation. Nature 413, 697–698 (2001)

    ADS  CAS  Article  Google Scholar 

  6. 6

    Higdon, J. J. L. & Corrsin, S. Induced drag of a bird flock. Am. Nat. 112, 727–744 (1978)

    Article  Google Scholar 

  7. 7

    Heppner, F. H. Avian flight formations. Bird-Banding 45, 160–169 (1974)

    Article  Google Scholar 

  8. 8

    Greene, P. R. & McMahon, T. A. Running in circles. Physiologist 22, S35–S36 (1979)

    CAS  PubMed  Google Scholar 

  9. 9

    Usherwood, J. R. & Wilson, A. M. Accounting for elite indoor 200 m sprint results. Biol. Lett. 2, 47–50 (2006)

    Article  Google Scholar 

  10. 10

    Usherwood, J. R. & Wilson, A. M. No force limit on greyhound sprint speed. Nature 438, 753–754 (2005)

    ADS  CAS  Article  Google Scholar 

  11. 11

    Pennycuick, C. J. Bird Flight Performance: A Practical Calculation Manual (Oxford Univ. Press, 1989)

    Google Scholar 

  12. 12

    Pennycuick, C. J., Klaasen, M., Kvist, A. & Lindström, Å. Wingbeat frequency and the body drag anomaly: wind-tunnel observations on a thrush nightingale (Luscinia luscinia) and a teal (Anas crecca). J. Exp. Biol. 199, 2757–2765 (1996)

    CAS  PubMed  Google Scholar 

  13. 13

    Bilo, D., Lauck, A. & Nachtigall, W. in Biona-Report 3 (ed. Nachtigall, W. ) 87–108 (Gustav Fischer, 1984)

    Google Scholar 

  14. 14

    Hedrick, T. L., Usherwood, J. R. & Biewener, A. A. Wing inertia and whole-body acceleration: an analysis of instantaneous aerodynamic force production in cockatiels (Nymphicus hollandicus) flying across a range of speeds. J. Exp. Biol. 207, 1689–1702 (2004)

    Article  Google Scholar 

  15. 15

    Tobalske, B. W., Hedrick, T. L., Dial, K. P. & Biewener, A. A. Comparative power curves in bird flight. Nature 421, 363–366 (2003)

    ADS  CAS  Article  Google Scholar 

  16. 16

    Schmidt-Wellenburg, C. A., Biebach, H., Daan, S. & Visser, G. H. Energy expenditure and wing beat frequency in relationship to body mass in free flying barn swallows (Hirundo rustica). J. Comp. Physiol. B 177, 327–337 (2007)

    Article  Google Scholar 

  17. 17

    Rayner, J. M. V. A vortex theory of animal flight. Part 1. The vortex wake of a hovering animal. J. Fluid Mech. 91, 697–730 (1979)

    ADS  Article  Google Scholar 

  18. 18

    Ellington, C. P. The aerodynamics of hovering insect flight. V. A vortex theory. Phil. Trans. R. Soc. Lond. B 305, 115–144 (1984)

    ADS  Article  Google Scholar 

  19. 19

    Spedding, G. R. & McArthur, J. Span efficiencies of wings at low Reynolds numbers. J. Aircr. 47, 120–128 (2010)

    Article  Google Scholar 

  20. 20

    Lilienthal, O. Birdflight as the Basis of Aviation (Markowski International, 2001) [transl.].

  21. 21

    Usherwood, J. R. Inertia may limit efficiency of slow flapping flight, but mayflies show a strategy for reducing the power requirements of loiter. Bioinspir. Biomim. 4, 015003 (2009)

    ADS  Article  Google Scholar 

  22. 22

    Pomeroy, H. & Heppner, F. Structure of turning in airborne rock dove (Columba livia) flocks. Auk 109, 256–267 (1992)

    Article  Google Scholar 

  23. 23

    Hedrick, T. L., Cheng, B. & Deng, X. Wingbeat time and the scaling of passive rotational damping in flapping flight. Science 324, 252–255 (2009)

    ADS  CAS  Article  Google Scholar 

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Acknowledgements

We would like to thank T. Hubel, H. Chapman, V. Unt and T. Demes for practical assistance, and The Wellcome Trust (J.R.U.), The Royal Society (A.M.W.), BBSRC (K.R.) and EPSRC for funding.

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Contributions

J.R.U. and A.M.W. conceived and designed the project. J.R.U. analysed the data, and wrote the paper with input from all other authors. M.S. trained the pigeons and helped perform the experiments. J.C.L., K.R. and A.M.W. developed and built the equipment.

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Correspondence to James R. Usherwood.

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The authors declare no competing financial interests.

Supplementary information

Supplementary Information

The file contains Supplementary Methods and Supplementary Tables 1-2. (PDF 263 kb)

Supplementary Movie 1

The movie shows up to 18 pigeons flying in a flock measured with back-mounted GPS and Inertial Measurement Units in June 2010. GPS measurements and logging are activated in response flapping, as identified from the dorsal accelerometer signal. This enables sufficient battery life for continuous field deployment of over two days. The tails show the paths taken in the previous 10 seconds; tail width is proportional to height; tail colours distinguish individual pigeons. Head colours represent flapping frequency above (red) or below (blue) average for each pigeon. Playback rate triple actual rate. (MOV 26519 kb)

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Usherwood, J., Stavrou, M., Lowe, J. et al. Flying in a flock comes at a cost in pigeons. Nature 474, 494–497 (2011). https://doi.org/10.1038/nature10164

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