On a few occasions in the Otway Ranges of SW Victoria, I've seen
honeyeaters (Red & Little Wattlebird, New Holland & Crescent Honeyeater)
feeding from the sap-tapping incisions made on the trunks of Eucalyptus
trees by the nocturnal marsupial Yellow-bellied Glider (YBG) (Petaurus
australis). With admittedly limited searching, I can only find one
published reference to this secondary use, that of Bridled Honeyeaters
using YBG incisions on Bloodwoods in North Queensland (Rupert Russell,
"Spotlight on Possums", 198*). I'm pretty sure I've heard/read other
accounts, but where?? I'm thinking of writing it up as a small note,
but I'd be interested to hear from anyone else who might have observed
the same thing, or similar.
The free availability of sugar-rich phloem sap, otherwise unavailable
(or randomly available through tree injuries of one kind or another), to
other animals in particular areas of the forest utilised in this way by
YBGs must be ecologically significant. Use of these fast food outlets
is certainly also made by other nocturnal possums such as the Common
Brushtail Possum (Trichosurus vulpecula), Sugar Glider (P. breviceps)
and Feathertail Glider (Acrobates pygmaeus). Sugar Gliders also incise
trees, but not so deeply & extensively as YBGs, & not with the same
potential for sap flow. The YBG sap sites are used & territorially
defended by the diurnal butterfly, Australian Admiral (Vanessa itea).
Various diurnal flys & wasps also visit them. Any concentrations of
nocturnal insects using the sites may provide foraging loci for
insectivorous bats & other small mammals (Antechinus stuartii/agilis,
Acrobates pygmaeus, etc.).
All ideas, thoughts & contributions gratefully received.
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