Invasive parasites in the Galápagos Islands may leave some Darwin’s tree finches singing the blues.
The nonnative Philornis downsi fly infests the birds’ nests and lays its eggs there. Fly larvae feast on the chicks’ blood and tissue, producing festering wounds and killing over half of the baby birds. Among survivors, larval damage to the birds’ beaks may mess with the birds’ songs when they’re older, possibly affecting their appeal to potential mates, researchers report June 12 in Proceedings of the Royal Society B.
“What’s heartbreaking, when you’re walking through this beautiful forest, is to hear these medium tree finch males just singing and singing and not being able to attract a mate,” says Sonia Kleindorfer, a behavioral ecologist at Flinders University in Adelaide, Australia and the University of Vienna.
The fly arrived in the Galápagos probably in the 1960s. The researchers studied two finch species on Floreana Island that the fly larvae plague: the critically endangered medium tree finch (Camarhynchus pauper) and the related small tree finch (C. parvulus).