They investigated life history data of nearly 1400 bird species and found that
avian life span varies considerably across the entire Earth, and that much of this variation can be explained
by the species» body mass and clutch size and
by the local diversity of
predator species.
«As with all good studies, this one generates many new questions,» says Staffan Bensch, an animal ecologist at Lund University in Sweden, who wonders whether the virus has benefitted some songbird species
by killing off their
avian predators, jays and crows.