Kinship and paternity studies in birds

Behavioural rules and their fitness consequences in a cooperative breeding system.

 Long-tailed tit (Aegithalos caudatus)
Long-tailed tit (Aegithalos caudatus)

Principal Investigator: Professor Ben Hatchwell

Cooperative breeding systems have been invaluable in the testing of many important evolutionary theories. However, there are still major unresolved questions concerning the rules and mechanisms that determine an individual's behaviour, and the consequences of these rules for the evolution of cooperation.

The project will address three related questions concerning the evolution of cooperative breeding:

  1. What parental investment rules do helpers and breeders use when making provisioning decisions ?
  2. What is the mechanism of kin recognition and discrimination?
  3. What are the consequences of those rules and mechanisms for the fitness of cooperating individuals?

This project will answer these questions using the unique cooperative breeding system of the long-tailed tit, Aegithalos caudatus as a model system. Observations of natural variation and experiments will be used to determine how investment varies with kinship discrimination and the number of investors in a brood.

The mechanisms of kin discrimination will be investigated by switching nestlings between nests and by playback experiments. In addition to the indirect fitness benefits of helping kin, helpers may also derive direct fitness benefits through enhanced future reproductive success; the existence of direct fitness benefits will also be tested by observation and experimentation.

The extraordinary cooperative breeding system of long-tailed tits is characterised by weak constraints on independent breeding and low reproductive skew. This study will therefore offer valuable insights into the critical ecological and demographic differences between cooperative and non-cooperative species, and will enable key predictions of recent reproductive skew models to be tested.

The objectives of this study are all contingent on determining the kinship of individuals in the study population. Nine primers have been identified, sufficient to determine relatedness. Genetic profiling will be performed using an ABI 377 DNA Sequencer using these primers.


Hatchwell BJ, Ross DJ, Chaline N, Fowlie MK, Burke T (2002) Parentage in the cooperatie breeding system of long-tailed tits Aegithalos caudatusAnimal Behaviour (in press)

Hatchwell BJ, Anderson C, Ross DJ, Fowlie MK, Blackwell PG (2001) Social organisation of cooperatively breeding long-tailed tits: kinship and spatial dynamics. Journal of Animal Ecology 70: 820-830.

Hatchwell BJ, Ross DJ, Fowlie MK & McGowan A (2001) Kin discrimination in cooperatively breeding long-tailed tits. Proceedings of the Royal Society, Series B 268: 885-890.

Russell AF & Hatchwell BJ (2001). Experimental evidence for kin-biased helping in a cooperatively breeding vertebrate. Proceedings of the Royal Society, Series B 268: 2169-2174.

Background references

Hatchwell BJ (1999) Investment strategies of breeders in cooperative breeding systems. American Naturalist, 154, 205-219.

Komdeur J & Hatchwell BJ (1999) Kin recognition in avian societies. Trends in Ecology and Evolution 14, 237-241.

Hatchwell BJ, Fowlie MK, Ross DJ, Russell AF (1999) Incubation behavior of Long-tailed Tits: Why do males provision incubating females? Condor, 101, (3), 681-686.

Hatchwell BJ, Russell AF, Fowlie MK, Ross DJ (1999) Reproductive success and nest-site selection in a cooperative breeder: Effect of experience and a direct benefit of helping. The Auk 116, (2), 355-363.

Hatchwell BJ & Russell AF (1996) Provisioning rules in cooperatively breeding long-tailed tits. Proceedings of the Royal Society, Series B, 263, 83-88.


Mr Nicolas Chaline (Oct 1999 - Feb 2000)

Dr Douglas Ross (Jan 1998 - Sept 1999)


Professor Ben Hatchwell

Professor Tim Birkhead

Professor Terry Burke

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