The impacts of habitat urbanization on birds’ breeding biology, demography, behavior and genetics

Urbanization is one of the major threats to global biodiversity. Compared to the more natural habitats, the environmental and ecological conditions (e.g. microclimate, food availability, predation risk or disturbance) are substantially altered in urban areas, exerting diverse effects on the diversity, individual and population level characteristics of urban wildlife. Our aim is to explore and understand these effects using the Great tit (Parus major) as a model species. To achieve this we are working at several urban and forest locations and also along urban-to-rural gradients in Hungary, utilizing an ongoing monitoring system (started in 2013) that is based mostly on colour ringed (i.e., individually identifiable) individuals. The project is structured in several main topics, introduced below in brief.

First, we are measuring reproductive success and phenology, nestling and adult survival, and also recruitment to explore the long-term differences, trends and year-to-year fluctuations in urban and non-urban great tit populations. By combining these parameters we also aim to build demographic models to understand the dynamics and functioning of urban and forest bird populations.

Second, to better understand the ecological drivers and their relative importance in urban and non-urban environments, we also study the relationships between birds’ breeding success components or morphological traits (e.g. morphology, feather structure) and local climate (e.g. temperature, extreme meteorological events) or food availability during the breeding season (e.g. caterpillar biomass in birds’ environments and nestling food composition).

Third, we also study various components of birds’ behaviour that might be affected by urban environments, like problem-solving, explorative and nest defending behaviour, risk-taking towards humans and predators, or the behavioural impacts of such commonly used techniques in field ornithology, like individuals’ capture on their nests or the presence of a small video camera on the nest box. To achieve this we use field and lab experiments as well, and our earlier studies also involved one of the most widespread urban bird, the House sparrow (Passer domesticus), as a model species.

Finally, we use genetic tools to study e.g. the frequency of extra-pair paternity or offspring sex ratio in urban and non-urban great tit populations. Additionally, we also aim to investigate the genetic background of urban birds’ ‘behavioural phenotype’ by exploring associations between the components of behaviour, like tolerance towards human disturbance or problem-solving success, and the frequency of certain candidate gene loci (DRD4, SERT) that might play important roles in the development of these traits.

Some key publications:

  • Food availability limits avian reproduction in the city: An experimental study on great tits Parus major. Seress G, Sándor K, Evans KL, Liker A. 2020Journal of Animal Ecology, DOI: 10.1111/1365-2656.13211
  • Impact of urbanization on abundance and phenology of caterpillars and consequences for breeding in an insectivorous bird. Seress G, Hammer T, Bókony V, Vincze E, Preiszner B, Pipoly I, Sinkovics Cs, Evans KL, Liker A. 2018Ecological Applications, DOI: 10.1002/eap.1730
  • Does urbanization affect predation of bird nests? A meta-analysis. Vincze E, Seress G, Lagisz M, Nakagawa S, Dingemanse NJ, Sprau P. 2017Frontiers in Ecology and Evolution, DOI: 10.3389/fevo.2017.00029
  • Problem-solving performance and reproductive success of great tits in urban and forest habitats. Preiszner B, Papp S, Pipoly I, Seress G, Vincze E, Liker A, Bókony V. 2017Animal Cognition. DOI: 10.1007/s10071-016-1008-z
  • Lean birds in the city: body size and condition of house sparrows along the urbanization gradient. Liker A, Papp Z, Bókony V, Lendvai ÁZ. 2008. Journal of Animal Ecology 77 (4), 789-795