Polyandry, cloaca-pecking and sperm competition in dunnocks


A variety of behaviours adopted by males before and after copulation serve to increase paternity. The most spectacular examples occur in insects where males increase their own chances of fertilizing the female's eggs by mate guarding, mating plugs and even removal of other males' sperm1,2. Here, sperm competition is described for a small European passerine bird, the dunnock (Prunella modularis), where females are often mated simultaneously to two males3,4 and where there is an elaborate pre-copulatory display5,6. It is shown that, during this display, the male stimulates the female to eject sperm before he himself copulates. The display is most intense where there is a high probability that another male has recently mated with the female.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Parker, G. A. Biol. Rev. 45, 525–568 (1970).

  2. 2

    Waage, J. K. Science 203, 916–918 (1979).

  3. 3

    Birkhead, M. E. Ibis 123, 75–84 (1981).

  4. 4

    Snow, B. & Snow, D. Misc. Publ. Yamashina Inst. (in the press).

  5. 5

    Delamain, J. Br. Birds 23, 19–20 (1929).

  6. 6

    Harrison, C. J. O. & Binfield, F. G. Bird Study 14, 192–193 (1967).

  7. 7

    Birkhead, T. R. Anim. Behav. 30, 277–283 (1982).

  8. 8

    Sanderson, R. F. Bird Study 15, 213 (1968).

  9. 9

    Lake, P. E. in Form and Function in Birds (eds King, A. S. & McLelland, M.) 1–62 (Academic, London, 1981).

  10. 10

    Gilbert, A. B. Adv. Reprod. Physiol. 2, 111–179 (1967).

  11. 11

    Howarth, B. in The Oviduct and its Functions (eds Johnson, A. D. & Foley, C. W.) 237–270 (Academic, London, 1974).

  12. 12

    Stacey, P B. Am. Nat. 120, 51–64 (1982).

  13. 13

    Humphreys, P. N. J. Reprod. Fert. 29, 327–336 (1972).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Davies, N. Polyandry, cloaca-pecking and sperm competition in dunnocks. Nature 302, 334–336 (1983). https://doi.org/10.1038/302334a0

Download citation

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.