Urbanisation is a dominant demographic trend and an important component of the earth's global transformation. It has unprecedented socioeconomic, cultural and environmental implications, and poses a threat to the conservation of biodiversity, as it can provoke alterations in ecological systems and lead to poor functioning of urban systems as they are currently structured. From the ecological point of view, the city is a fragmented, heterogeneous, complex mosaic of habitats, including ecosystems with different degrees of alteration. Urban systems contain only small areas of fragments of original vegetation and/or artificial green spaces, leading to a drastic decrease from their original abundance and diversity. However, green spaces, including original fragments, can help to conserve bird diversity, improving the functioning of these artificial systems in the medium term. This study looks at the characteristics and benefits of urban ecology in the framework of sustainable development, and carries out a meta-analysis of research into bird diversity in four cities in southern Chile, using ecological indices (Shannon-Wiener, β diversity between cities). The results reveal that there is low evenness in the four cities and that the city with the highest evenness is Valdivia (J = 0.78). There is clear dominance by a few bird species (e.g. the exotic species house sparrow Passer domesticus and rock pigeon Columba livia, and the native species rufous-collared sparrow Zonotricia capensis, austral thrush Turdus falklandii, southern lapwing Vanellus chilensis, and chimango caracara Milvago chimango). β diversity is low as the four cities show similarity greater than 50%. Birds reject paved surfaces in squares and prefer areas with native bushes and trees, with nearby bodies of water and large spaces (parks rather than squares). The study proposes technical recommendations and suggests further research.