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The forty-spotted pardalote (Pardalotus quadragintus) is a small Tasmanian bird whose future has been under threat. However, a trial protection program has achieved the sort of success most conservation projects can only dream of.
The pardalote is threatened in part by the relentless logging of Tasmania's native forests, but also the rise of the parasitic fly Passeromyia longicornis. The flies lay their eggs in pardalote nests so the maggots can feed on the blood of newly hatched chicks. It is thought the flies have been preying on the birds for a long time, but Australian National University PhD student Fernanda Alves told IFLScience their impact seems to be increasing.
Alves added it is not clear whether this is because the birds are more stressed, and therefore vulnerable, or if climate change is benefiting the fly. Either way the consequences are devastating, with 90 percent of chicks never reaching adulthood in some parts of the pardalotes' range.
Previous attempts to save the pardalotes have proven that spraying their nests with insecticides works, but it isn't very practical. Wildlife officers would need to find the nests, climb high into trees to spray them, and hopefully not distress the birds in the process.
In Animal Conservation, Alves shows there is another way. Pardalotes use feathers to make their nests soft. Not producing enough of their own, they scavenge those dropped by other birds. Alves told IFLScience that despite their own sharp attire, pardalotes are not too fussed about interior decorating, using anything from brightly colored rosella feathers to raven feathers for a gothic touch.
Alves treated chicken feathers with insecticides and left them close to trees with pardolote nests. Other nests were given untreated feathers as a control. With 38 nests in the sample and an average of four chicks per nest, this looked like enough for a statistically significant sample. In the end, however, the results were so striking Alves could have proven her point with fewer birds.
“The results were fantastic. Birds took the treated feathers back to their nests and as a result 95 percent of the chicks survived – whereas those that used untreated feathers had only an 8 percent survival rate,” Alves said in a statement.
Alves told IFLScience there were no other species of birds in her study area likely to benefit in the same way, but “a lot of other species use feathers as soft material, others prefer fur. [The technique] could be used in the tropics,” where pest threats are more common.
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Unlike an insecticide recently found to threaten birds, the one Alves used is commonly applied to caged birds. As to the big question, Alves confirmed some of her sample birds have exactly 40 spots, but others have more or less.
