Urban environments create novel challenges and opportunities for birds. Understanding why and how some birds are able to adapt to urban landscapes, and others are not, is important to predict how ongoing urbanisation is likely to impact birds. This project aims to understand how birds in human-altered landscapes cope with the opportunities and pressures of human life.
Red-winged Starlings Onychognathus morio have developed a reputation amongst the UCT community for being sly, lunch-thieving pests. Since 2017 we have studied how these birds cope with highly variable food quality and quantity in urban environments, the stresses of sharing their space with large numbers of people, and of high summer temperatures as Cape Town’s climate warms. Early correlative work showed that adult starlings benefit from high availability of anthropogenic food, gaining more weight on weekdays than on weekends, but that chicks seem to suffer, with those experiencing many high human presence days while in the nest showing reduced growth compared to those raised during lower human presence days (i.e. those whose nestling period overlaps with public holidays and vacations).
Miqkayla Stofberg’s supplementary feeding experiment in 2020/21 showed less clear morphological differences between nestlings fed different diets. We therefore hypothesize that negative impacts of high human presence on nestling growth may be mediated by stress effects associated with adult nest defence behaviours (breeding adults frequently divebomb passers-by when nests contain nestlings). New MSc student Abiodun Ademola will be investigating this hypothesis for her thesis. In 2021, BSc Hons student Kagiso Nhlapo showed that faecal glucocorticoid metabolite concentrations in starling droppings were negatively correlated with human foot traffic levels outside of the breeding season. Abiodun will also assess whether this pattern might be reversed during breeding.
Activities in 2022
- Abiodun Ademola arrived from Nigeria to start a MSc by dissertation on a Mastercard scholarship. Abiodun’s project focuses on understanding the effect of fluctuations in human foot traffic on stress levels in adult and nestling Red-winged Starlings, using faecal glucocorticoid metabolites as a proxy for stress. She is also investigating the downstream impacts on fitness by measuring body mass changes and reproductive success. Abiodun is supervised by Susie Cunningham and Celiwe Ngcamphalala.
- A highly successful trapping effort in mid-2022 saw 41 new colour-ringed starlings added to the study population. This brings the total number of adults starlings ringed during the course of the project to 277. An additional 221 nestlings have been ringed in the nest.
- Body mass maintenance and breeding monitoring continued throughout 2022: these data will be used to investigate the effects of societal recovery from the COVID-19 pandemic on the productivity of urban wildlife.
- Miqkayla Stofberg completed her PhD, which is under examination at the time of writing.
- Miqkayla also published her paper on the relationships between temperature, behaviour and body mass in urban starlings in the journal Landscape and Urban Planning.
- Former CB MSc student Varalika Jain (2020 cohort) published her dissertation research on the impacts of anthropogenic food sources on the movement ecology of ravens in the journal Movement Ecology.
Impact of the project
Studying the starlings on campus has allowed us to involve the wider university community in a citizen science project, making our research more visible and relevant. The accessibility of the project and its fieldwork has also resulted in an ideal training opportunity for younger students wanting to gain experience in behavioural research and bird observation/handling under careful supervision.
DSI-NRF CoE grant; NRF-STINT South Africa-Sweden Research Collaboration; NRF ACESS grant.
Research team 2022
A/Prof. Arjun Amar (FIAO, UCT)
A/Prof. Res Altwegg (SEEC, UCT)
Dr Pippin Anderson (EGS, UCT)
Dr Martin Andersson (MEEL, Lund University)
A/Prof. Susan Cunningham (FIAO, UCT)
Dr Celiwe Ngamphalala (BioSci, UCT)
Dr Arne Hegemann (MEEL, Lund University)
Dr Sally Hofmeyr (FIAO, UCT)
A/Prof. Caroline Isaksson (MEEL, Lund University)
Dr Johan Nilsson (OIKOS office, Lund University)
Dr Petra Sumasgutner (KLF, University of Vienna)
A/Prof. Robert Thomson (FIAO, UCT)
Dr Hannah Watson (MEEL, Lund University)
Students: Miqkayla Stofberg (PhD, UCT); Jessleena Suri (PhD, UCT); Abiodun Ademola (MSc, UCT).
Volunteers: Timothy Aikins Khan, Mandla Dube, Carla du Toit, Yuzra Eksteen, Kimberlyn Greenwood, Lebogang Nkgudi, Mila Truter and many others.