AIR pollution causes the plumage of great tits to fadeand may make it more difficult for them to breed. Sulphur and heavy metals can kill the caterpillars from which great tits obtain the pigments that are the key to their sexual attractiveness, say researchers in Finland.
Tapio Eeva and his colleagues at the University of Turku studied 500 nesting boxes used by great tits (
The researchers found that the intensity of the yellow coloration in the breast plumage of nestlings increased the farther they were from the smelter. The density of caterpillars rose with distance from the smelter as well.
Nestlings farther from the smelter also weighed more (
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