3 March 2016
An endangered Tasmanian songbird doesn’t have to wait for manna from heaven: it goes out and gathers its own.
The forty-spotted pardalote (Pardalotus quadragintus) is the first Australian bird found to deliberately encourage trees to release manna, a sugary crystallised sap. In doing so it not only provides food for its young but might also engineer the environment in a way that benefits other Tasmanian animals.
Samuel Case and Amanda Edworthy of the
University in spent the second half of 2014
monitoring the birds, whose population has plummeted by 60 per cent in the last
18 years. “We were ecstatic and surprised to discover a novel foraging
behaviour,” says Case. Canberra
The birds deliberately clip the leaf stalks of the manna-gum tree, a species of eucalyptus, with their bills. In many cases the tree responds to the wounds by exuding sticky and nutritious manna gum over the next few days, which the birds harvest. Biologists call this foraging behaviour “mining” or “farming”.
“Mining for tree exudates is an unusual foraging behaviour among birds,” says Case. “This is the first record of an Australian bird that mines trees.”
“The behaviour of the forty-spotted pardalotes is strikingly similar to North American sapsuckers,” says Laurie Eberhardt at
who studies similar behaviour in North American birds. “Especially interesting
is the way the pardalotes returned to the same holes and widened them over
time.” This is something that sapsuckers do too. Indiana