Honorary Research Associates

Dr Rita Covas

  Dr Rita Covas
  PhD (Cape Town)


Rita completed her undergraduate studies at the University of Lisbon which included a graduation dissertation on the biogeography of Mediterranean birds at the CNRS in Montpellier, France, with Jacques Blondel. After that she worked on the seabird community of Sao Tome and Principe in the Gulf of Guinea, West Africa with Luis Monteiro and Martim Melo.

In 1998 Rita moved to Cape Town to start a PhD on cooperative breeding in sociable weavers at the Percy FitzPatrick Institute with Morné du Plessis. She then moved to the University of Edinburgh and is currently a Marie Curie fellow at the CEFE-CNRS, Montpellier, France.

The central themes of Rita's research are the evolution of kin sociality and life-histories in birds and the relationship between the two. She has been working on cooperative breeding and helping behaviour on the sociable weaver Philetairus socius, since 1998. This has involved collaboration with several people and, in particular, Claire Doutrelant (CEFE-CNRS, France). She is currently also collaborating with Michael Griesser (Uppsala University, Sweden) in a study of the evolution of family group living across species.

Rita's other major research topic is trying to understand broad patterns of variation in life-history and behaviour, particularly evolution on islands and latitudinal patterns. She has an ongoing field study in the gulf of Guinea islands, West Africa, where she studied factors related to life-history variation and adaptations to the island environment. More specifically, she is investigating the relationship between blood parasite levels, immunity and the life-history characteristics, secondary sexual traits and mating systems of bird species in this region. This research is being done in collaboration with Martim Melo (CEFE-CNRS, France), Jon Beadell and Robert Fleischer (Smithsonian Institute, USA) and Staffan Andersson (Goteborg University, Sweden).

Rita is also using museum collections and literature-based data to investigate whether there are global patterns of life history trait adaptation on islands, particularly in morphology and sexual ornamentation. This is also a collaborative study together with with Claire Doutrelant, Arnaud Gregoire and Pierre-Andr Crochet (CEFE-CNRS, France).

Current students (UCT)

Kyle-Mark Middleton: The individual bases of group behaviour in the cooperative breeding Southern Ground-Hornbill Bucorvus leadbeateri. (Co-supervisors: Claire Spottiswoode, Kate Carstens and Fanny Ryback)

Recent peer-reviewed publications


Lobato, E., Doutrelant, C., Melo, M., Reis, S. and Covas, R. 2017. Insularity effects on bird immune parameters: a comparison between island and mainland populations in West Africa. Ecology and Evolution 7: 3645-3656. 


Doutrelant, C., Paquet, M., Renoult, J.P., Grégoire, A., Crochet, P-A., and Covas, R. 2016. Worldwide patterns of bird colouration on islands. Ecology Letters 19: 537-545.

Lobato, E., Geraldes, M., Melo, M., Doutrelant, C. and Covas, R. 2016. Diversity and composition of cultivable gut bacteria in an endemic island bird and its mainland sister species. Symbiosis.

Paquet. M., Doutrelant, C., Loubon, M., Theron, F.,  Rat, M. and Covas, R. 2016. Communal roosting, thermoregulatory benefits and breeding group size predictability in cooperatively breeding sociable weavers. Journal of Avian Biology 47(6): 749-755.


Aucker, P., Gregoire, A., Rat, M., Spottiswoode, C.N., van Dijk, R.E., Paquet, M., Kaden, J., Pradel, R., Hatchwell, B.J., Covas, R.* & Doutrelant, C.* 2015. Disruptive viability selection on a black plumage trait associated with dominance. Journal of Evolutionary Biology 28: 2027–2041 (*These two authors contributed equally to this study)

Paquet, M., Doutrelant, C., Hatchwell, B.J., Spottiswoode, C.N. & Covas, R. 2015.Antagonistic effect of helpers on breeding male and female survival a cooperatively breeding bird. Journal of Animal Ecology 84: 1354–1362.

van Dijk, R.E., Covas, R., Doutrelant, C., Spottiswoode, C.N. & Hatchwell, B.J. 2015. Fine-scale genetic structure reflects sex-specific dispersal strategies in a population of sociable weavers (Philetairus socius). Molecular Ecology 24: 4296–4311.

Paquet, M., Covas, R. & Doutrelant, C. 2015. A cross-fostering experiment reveals that prenatal environment affects begging behaviour in a cooperative breeder. Animal Behaviour 102: 251-258.

Rat, M., van Dijk, R,E., Covas, R., & Doutrelant, C 2015. Dominance hierarchies and associated signalling in a cooperative passerine. Behavioral Ecology and Sociobiology 69: 437-448.


Altwegg, R., Doutrelant, C., Anderson, M.D., Spottiswoode, C.N. & Covas, R. 2014 Climate, social factors and research disturbance influence population dynamics in a declining sociable weaver metapopulation. Oecologia 174: 413–425.

Paquet, M., Covas, R., Chastel, O., Parenteau,C. & Doutrelant, C. 2013. Maternal effects in relation to helper presence in the cooperatively breeding Sociable Weaver. PLoS ONE 8(3): e59336.

Van Dijk, R.E., Kaden, J.C., Argueelles-Tico, A., Beltran, L.M., Paquet, M., Covas, R., Doutrelant, C. & Hatchwell, B.J. 2013. The thermoregulatory benefits of the communal nest of sociable weavers Philetairus socius are spatially structured within nests. Journal of Avian Biology 44:102-110.

Covas, R. 2012. Evolution of reproductive life histories in island birds worldwide. Proceedings of the Royal Society of London B, 279, 1531-1537. doi:10.1098/rspb.2011.1785.

Covas, R., Deville, A.S., Doutrelant, C., Spottiswoode, C.N. & Gregoire, A. 2011. The effect of helpers on the postfledging period in a cooperatively breeding bird, the sociable weaver. Animal Behaviour 81:121-126.

Doutrelant, C., Dalecky, A. & Covas, R. 2011. Age and relatedness have an interactive effect on the feeding behaviour of helpers in cooperatively breeding sociable weavers. Behaviour 148:1399-1417.

Beadell, J.S., Covas, R., Melo, M., Ishtiaq, F., Perkins, S.L., Graves, G.R., Fleischer, R.C. 2009. Host associations and evolutionary relationships of avian blood parasites from West Africa. International Journal of Parasitology: 39: 257-266.