From forest edge to city park: how birds adapt to urban life

City parks, often embedded in a highly altered city fabric, are sometimes the only types of natural areas within human settlements. Their importance for both city dwellers and biodiversity is well known, yet parks in Eastern-Central European cities still offer much to study, for example, how their situation within the urban matrix can affect wildlife, and which animal traits facilitate or limit the survival of certain species. A new study reveals the potential of city parks to retain bird diversity, compared to the surrounding landscapes near the cities.

The research was carried out by an international group from the HUN-REN Centre for Ecological Research, with contributions from eight other institutes in Hungary and Romania. Published in Urban Forestry & Urban Greening, the study examines how landscape complexity and the spatial configuration of city parks affect bird community composition and functional trait variation. “We found that bird species richness in city parks was lower than in forest edges but similar to that of agricultural habitats,” explains lead author Tamás Lakatos. “This shows that while parks cannot entirely substitute for natural forests, they remain important components of urban ecosystems.”

The researchers recorded birds in 72 city parks across 9 mid-sized cities in Hungary and Romania. In each city, eight sampling sites were delineated: two city parks located in the central part of the cities, two city parks in suburban areas, and four reference areas in the outer, less urbanised, so-called peri-urban areas. For better comparison, reference areas consisted either of forest-dominated habitat edges or primarily agricultural production areas. The team conducted bird surveys using point counts during the peak breeding season (April–May), in the early morning hours, with two repetitions. The researchers surveyed more than 3,000 birds representing 72 species, categorizing them by so called functional traits, like diet, foraging technique, nesting strategy, migratory status, body size, and feeding of nestlings. This approach allowed the team to assess how different functional traits influence birds’ ability to thrive in human-dominated settings, like city parks.

According to the findings, insect-feeding birds were less able to establish populations in urban parks due to the scarcity of suitable insect habitats. In contrast, species that nest in elevated places such as buildings often benefited, finding safe nesting opportunities away from predators like cats and dogs. “Ground-nesting birds face particular challenges in cities because of higher rates of nest predation and human disturbance,” notes Péter Batáry, the project leader and last author of the paper. “By contrast, cavity-nesting species such as tits can thrive if old trees or nest boxes are available.” Furthermore, agricultural fields provided more suitable habitats for larger-bodied birds, which require more extent foraging areas, while generalist species like blackbirds and house sparrows adapted well to urban parks also. However, the spatial configuration of parks, i.e. whether they were situated in suburban areas or in the city centres, has never played a role, meaning that their importance is consistent regardless of location. More specialised species, such as the yellowhammer or hoopoe, however, struggled to find appropriate habitats in urban environments.

The study highlights that city parks cannot maintain full bird diversity on their own, but they can significantly contribute to biodiversity conservation if managed thoughtfully. Measures such as reducing mowing frequency, planting native shrubs and trees, retaining old and dead wood, and installing nest boxes can all increase the natural value of parks for birds. “Our results emphasize that urban green spaces are not isolated patches but parts of a larger ecological network,” says Tamás Lakatos. “Sustainable city planning needs to consider this broader landscape perspective, integrating parks, farmland, and forests into a mosaic that allows most bird species to persist and ecosystem functions to be secured.”