Assessing Parasite Prevalence and Health Status of the Eurasian Tree Sparrow (Passer montanus) in Green Urban Areas of a Southern European City

Urban landscapes have given rise to novel ecosystems (e.g., green areas), which differ in design and ecological quality depending on local planning strategies. Europe has the goal to increase conservation through increasing greenspace; however, urban wildlife health impacts, particularly on birds, are poorly studied. This study investigates associations between haemosporidians and intestinal coccidia in the Eurasian Tree Sparrow (Passer montanus), as well as their body condition and immunological status, from five urban green areas in Madrid, Spain, from 2019 to 2022. These green areas differ in green infrastructure, and because these birds are adapted to urban environments, they are a good model to evaluate how green area infrastructure may affect the birds’ health. We detected a 29% prevalence of haemosporidians (Haemoproteus being the most common, followed by Leucocytozoon and Plasmodium) and a 4% prevalence of intestinal coccidia. We found that haemosporidian prevalence was significantly higher in green areas with untreated stagnant water surrounded by muddy areas, ideal conditions for vector reproduction. Therefore, effective management strategies, especially related to water treatment, are essential for protecting urban wildlife and human health. This study provides valuable information for researchers and urban wildlife managers to incorporate appropriate management strategies into urban green area planning to preserve urban biodiversity and protect public health.