PhD (Cape Town)

The central themes of Rita's research are the causes and consequences of sociality and life histories in birds. Rita uses a combination of field-based and comparative approaches. Her main study system is a long-term study on Sociable Weavers, a colonial cooperative bird with a complex social structure, based at Benfontein Nature Reserve. This has been conducted in collaboration with several people, in particular Claire Doutrelant (CEFE-CNRS, France). Since 2017 Rita has coordinated the Fitz-based long-term study on Southern Ground-Hornbills, another group-living, cooperative species that is currently listed as ‘Endangered’ in South Africa. This study is based at the Associated Private Nature Reserves near Hoedspruit.

Rita's other major research interest is evolution on islands. Island systems are wonderful ‘natural laboratories’ and Rita has been conducting comparative and field-based research to unravel patterns of adaptation in island birds worldwide as well as the mechanisms underlying these changes. Previous studies focused, for example, in patterns of parallel evolution in reproductive life-histories and plumage colouration. The field component of this work is conducted mostly in the Gulf of Guinea islands and adjacent mainland in Gabon and Cameroon, West Africa. Here, Rita has investigated blood parasites, immunity and secondary sexual traits (colour and song). This research is being done in collaboration with Claire Doutrelant, Martim Melo (CIBIO, University of Porto), and Claire Loiseau (CIBIO, University of Porto).

About Rita:

Rita is a Principal Researcher at CIBIO (University of Porto, Portugal) and an Honorary Research Associate at the Fitz. She completed her undergraduate studies at the University of Lisbon, which included a graduation dissertation on the biogeography of Mediterranean birds conducted at the CNRS in Montpellier, France, with Jacques Blondel. After graduating, she obtained a BP Conservation Award, to work on the poorly known seabird community of São Tome and Principe in the Gulf of Guinea, West Africa together with Luis Monteiro (University of the Azores) and Martim Melo (now at CIBIO, University of Porto).

In 1998 Rita moved to Cape Town to start a PhD at the Percy FitzPatrick Institute studying cooperative breeding behaviour in the Sociable Weaver under the supervision of Morné du Plessis. After her PhD, she moved to the University of Edinburgh and started to work on the birds from the Gulf of Guinea islands. Later she obtained a Marie Curie fellowship to expand this work at the CEFE-CNRS in Montpellier, France. At the end of 2008 Rita returned to South Africa to re-launch the sociable weaver study and became a Research Associate at the Fitz. In 2010 she obtained a position as a researcher at CIBIO (University to Porto, Portugal), where she currently works as a Principal Researcher. She has been an Honorary Research Associate of Fitz since 2015.

Current students (UCT)

Carrie Hickman (MSc): Climate change impacts on breeding success in Southern Ground Hornbills. (Co-supervisor: Susie Cunningham)

Recent peer-reviewed publications

2024

Bliard, L., Dufour, P., Griesser, M. and Covas, R. 2024. Family living and cooperative breeding in birds are associated with the number of avian predators. Evolution. https://doi.org/10.1093/evolut/qpae058

D’Amelio, P.B., Silva, N.J., Silva, L.R., Ferreira, A.C., Theron, F., Doutrelant, C. and Covas, R. 2024. Highly variable breeding phenology in an arid region colonial cooperative breeder, the Sociable Weaver Philetairus socius. Ostrich. https://doi.org/10.2989/00306525.2024.2328654

D'Amelio, P.B., Covas, R., Ferreira, A.C., Fortuna, R., Silva, L.R., Theron, F., Rybak, F. and Doutrelant, C. 2024. Benefits of pair-bond duration on reproduction in a life-long monogamous cooperative passerine. American Naturalist 203(5).  https://doi.org/10.1086/729436

Fortuna, R., Covas, R., D'Amelio, P.B., Silva, L.R., Parenteau, C., Bliard, L., Rybak, F., Doutrelant, C. and Paquet, M. 2024. Interplay of cooperative breeding and predation risk on egg allocation and reproductive output. Behavioral Ecology 35(2).  https://doi.org/10.1093/beheco/arae010

Silva, N.J., Benoit, F., Elliott, A., Rault, C., Colençon, P., Covas, R. and Doutrelant, C. 2024. Sex and age differences in the preference for materials for the communal nests of sociable weavers Philetairus socius . Ethology.  https://doi.org/10.1111/eth.13472

2023

Melo, M., Covas, R., Lima, R.F., Veiga da Horta, O., do Bom Jesus, C., Barros da Veiga, M., Samba, S., Fonseca, R., Cabinda, G., Viegas, L., Silva, T.L., Mata, V.A., Beja, P., Ferreira, S. 2023. DNA Barcode library of the endemic-rich avifauna of the oceanic islands of the Gulf of Guinea. Biodiversity Data Journal 11.  https://doi.org/10.3897/BDJ.11.e110428

Fortuna, R., Paquet, M., Biard, C., Élard, L., Ferreira, A.C., Leroux-Coyaux, M., Parenteau, C., Silva, L.R., Théron, F., Covas, R. and Doutrelant, C. 2023. Egg components and offspring survival vary with group size and laying order in a cooperative breeder. Oecologia 202: 129-142. https://doi.org/10.1007/s00442-023-05379-w

Halupka, L., Arlt, D., Tolvanen, J., Millon, A., Bize, P., Adamík, P., Albert, P., Arendt, W.J., Artemyev, A.V., Baglione, V., Bańbura, J., … and Covas, R. 2023. The effect of climate change on avian offspring production: A global meta-analysis. Proceedings of the National Academy of Sciences 120(19). https://doi.org/10.1073/pnas.2208389120

Ponti, R., Doutrelant, C. and Covas, R. 2023. Strength of the ‘island rule’ in birds is positively associated with absence of avian predators. Biology Letters 19(3). https://doi.org/10.1098/rsbl.2022.0536

2022

Covas, R., Lardy, S., Silva, L.R., Rey, B., Ferreira, A.C., Theron, F., Tognetti, A., Faivre, B. and Doutrelant, C. 2022. The oxidative cost of helping and its minimization in a cooperative breeder. Behavioral Ecology. https://doi.org/10.1093/beheco/arab152

2021

D’Amelio, P.B., Ferreira, A.C., Fortuna, R., Paquet, M., Silva, L.R., Theron, F., Doutrelant, C. and Covas, R. 2021. Disentangling climatic and nest predator impact on reproductive output reveals adverse high‐temperature effects regardless of helper number in an arid‐region cooperative bird. Ecology Letters 25: 151–162. https://doi.org/10.1111/ele.13913 IF: 9.492

Fortuna, R., Paquet, M., Ferreira, A.C., Silva, L.R., Theron, F., Doutrelant, C. and Covas, R. 2021. Maternal allocation in relation to weather, predation and social factors in a colonial cooperative bird. Journal of Animal Ecology 90: 1122–1133. https://doi.org/10.1111/1365-2656.13438 

Quque, M., Paquet, M., Zahn, S., Théron, F., Faivre, B., Sueur, C., Criscuolo, F., Doutrelant, C. and Covas, R. 2021. Contrasting associations between nestling telomere length and pre and postnatal helpers’ presence in a cooperatively breeding bird. Oecologia 196: 37-51. https://doi.org/10.1007/s00442-021-04917-8 

Reis, S., Melo, M., Covas, R., Doutrelant, C., Pereira, H., de Lima, R. and Loiseau, C. 2021. Influence of land use and host species on parasite richness, prevalence and co-infection patterns. International Journal for Parasitology 51(1): 83-94. https://doi.org/10.1016/j.ijpara.2020.08.005 

2020

Bliard, L., Paquet, M., Robert, A., Dufour, P., Renoult, J.P., Grégoire, A., Crochet, P.A., Covas, R. and Doutrelant, C. 2020. Examining the link between relaxed predation and bird coloration on islands. Biology Letters 16(4). https://doi.org/10.1098/rsbl.2020.0002 

Ferreira, A.C., Covas, R., Silva, L.R., Esteves, S.C., Duarte, I., Fortuna, R., Theron, F., Doutrelant, C. and Farine, D.R. 2020. How to make methodological decisions when inferring social networks. Ecology and Evolution. https://doi.org/10.1002/ece3.6568 

Ferreira, A.C., Silva, L.R., Renna, F., Brandl, H.B., Renoult, J.P., Farine, D.R., Covas, R. and Doutrelant, C. 2020. Deep learning-based methods for individual recognition in small birds. Methods in Ecology and Evolution 11: 1072-1085 https://doi.org/10.1111/2041-210X.13436