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Fungal infection in black kites increases in degraded environments

Black kites nestlings, Milvus migrans, en un nido. Foto: Guillermo Blanco

A study with participation of the Doñana Biological Station (EBD), the National Museum of Natural Sciences of Spain (MSCN) and the Royal Botanic Garden of Madrid (RJB), centres of the Spanish National Research Council (CSIC), shows that the presence of opportunistic fungal pathogens in oral lesions in nestling black kites (Milvus migrans), increases with the degradation of the habitat. The study, published in the Science of the Total Environment journal, has been carried out in the Parque Regional in the Southwest Madrid, where kites nest near the Manzanares and Jarama rivers, and in the Doñana National Park. This research work has interesting applications in conservation, since the infection and the fungi species detected in the birds could be used as indicators of the degradation level of an habitat.

"Avian scavengers, such as the black kite, are highly exposed to anthropogenic residues and contaminants. In addition, this species is good for studying the impact of the human activities in animals, since it inhabits both in well-conserved habitats and in altered environments. Early-life exposure to these contaminants may alter the composition of their microbiota and have negative effects on their life-long health", explains Aida Pitarch, researcher at the Complutense University in Madrid (UCM).

"In this research, we studied the presence of oral lesions in 38 nestlings from a highly degraded area in Southwest Madrid, where black kites nest in highly fragmented and contaminated forests along Manzanares and Jarama Rivers. We compared them with 105 nestlings from the Doñana National Park, in Huelva", points Fabrizio Sergio, researcher at the Doñana Biological Station (EBD-CSIC). "Oral lesions were found in 36.8% of the nestlings examined in Madrid, but in none of the ones examined in Doñana", says the researcher.

"Additionally, we studied the differences in the composition of the oral fungi community present in the nestlings, with or without lesions, from Madrid and Doñana area. We observed that the prevalence of opportunistic fungal pathogens was higher in Madrid than in Doñana. In addition, we identified fungi species that may provide protection against these pathogens in nestlings without lesions from both Madrid and Doñana. It was expected that these two types of fungi are affecting the birds in degraded and contaminated environments", add Javier Diéguez-Uribeondo and Laura Martín-Torrijos, researchers at the Royal Botanic Garden of Madrid (RJB-CSIC). "The conclusions of this study show that microbiota analyses of black kites nestlings may be used to measure the habitat status where these birds live, as well as the evolution of the pathogene fungi community and the risk of oral infection", conclude the researchers.


Pitarch, A., Diéguez-Uribeondo, J., Martín-Torrijos, L., Sergio, F., & Blanco, G. (2022). Fungal signatures of oral disease reflect environmental degradation in a facultative avian scavenger. Science of the Total Environment, 837, 155397. DOI: