Today, over half of humanity lives in cities and the expansion of urban areas is considered one of the greatest threats to biodiversity. Urbanization, negatively affects bird’s richness, abundances and reproduction because it constitutes a drastic habitat modification, and enhance inhospitable environment for many species. However, an important role of urban parks for bird’s populations, has been documented depending on park traits such as size, connectivity and vegetation structure. Moreover, despite the effect of parks, to understand the effects of urbanization on wildlife, an understudied driver of global biodiversity loss in urban context, is the simultaneous loss of biological and cultural diversity, and their replacement by cosmopolitan or exotic species. We aimed to explore the effect of park size, connectivity and native vegetation on bird’s populations and reproduction. At each season of 2014, bird richness and abundance were measured using 25 m fixed radius point counts in 51 urban parks. Then in 2015, we selected 17 parks, grouped in three-size categories: small (< 0.99 ha), medium (between 1 and 4.99 ha) and large (> 5 ha) and monitored every nest in the reproductive season to estimate the Mayfield reproductive index. Additionally, in spring 2014 in a subsample of ten parks, we surveyed 142 visitors, to understand the knowledge of birds and perceived diversity by urban citizens.
We recorded a total of 39 bird species (36 native and 3 exotic), and results showed that significantly higher richness was observed in large parks in contrast to medium size and small parks. A total of 112 nests of 7 native species were monitored. We did not find any relation among the proportion of native vegetation with bird richness or abundances and park size or vegetation, on the reproductive success of urban birds. Thus, despite lower diversity, small parks did not reduce reproductive success. Finally, we discovered that people recognized just a limited number of bird species, mainly exotic ones, despite these species were the minority of species listed on the survey. Additionally, we found no relationship between perceived and estimated bird diversity, suggesting that people tend to underestimate biodiversity in urban parks. These results highlight the importance of large parks for bird’s conservation in an urban context, and the relevance to the scientific community and naturalists to boost a better appreciation of our natural heritage, through more innovative mechanisms to stimulate the flow of information on local biodiversity.