A DIET of fast food has been blamed by French researchers for the fact that urban sparrows are getting smaller.
Scientists at the Centre national de la recherche scientifique captured 110 birds in two urban sites (Niort and La Rochelle) and two rural sites in the Poitou-Charentes.
They measured the size of the birds, the level of fat around the neck, the size of their beak, their feet and wings.
They found that adults sparrows in urban areas were 5%-10% smaller than their rural counterparts, however young urban sparrows were fatter than those in the country.
Biologist Frédéric Angelier said: “These data suggest that the urban sparrow has a diet that is too fatty.
“For healthy growth, the chicks must above all get protein via insects, however in the town they have more access to fatty foods thanks to man’s activities.”
The scientists have concluded that the diet does not threaten the survival of urban sparrows however they do lay fewer eggs.
Other factors such as noise and air pollution could also be factors, the report adds.
Photo: Flickr/Sander van der Wel