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DENVER/Sept. 27 – A recent scientific paper in the International Journal of Avian Science discusses how a lack of insect biodiversity in parks and other green spaces may be linked to the high mortality of baby scops owls in Madrid, Spain.

Since 1997, scops owlets living in the city have faced necrotic oropharyngeal disease, a parasitic condition that causes painful oral lesions and, in severe cases, bone damage. The disease affects roughly 90% of young owls in the city and often leads to starvation and death.

Morris Animal Foundation-funded researchers at Brinzal Owl Rescue Centre wanted to know why this disease was only known to infect scops owls in Madrid and not in other major European cities where they also live.

The study team searched the urban parks and green spaces that served as the city-dwelling owls’ hunting grounds, expecting to find insects they would typically consume, such as crickets, grasshoppers and beetles, but none were found. Instead, the researchers noted an abundance of a specific cockroach species that they identified as the intermediary host of the parasite and a primary food source for the owls and their chicks.

This finding suggests that today’s green spaces in Madrid are not a viable habitat for diverse prey species, severely limiting the owls’ natural diet selections and leading to the outbreak of this deadly disease.

"This study provides essential insights into the complex relationships within urban ecosystems and potential risks to wildlife and public health,” said Irene Hernandez-Tellez, the study’s principal investigator. “It also addresses an infectious disease specific to Madrid, offering invaluable tools to reduce its prevalence and enhance biodiversity conservation in urban areas."

About Morris Animal Foundation
Morris Animal Foundation’s mission is to bridge science and resources to advance the health of animals. Founded in 1948 and headquartered in Denver, it is one of the largest nonprofit animal health research organizations in the world, funding nearly $160 million in more than 3,000 critical animal health studies to date across a broad range of species. Learn more at

Media Contact: Annie Mehl