On Tue, 20 Feb 2001, michael hunter wrote:
> Are canetoad tadpoles toxic to birds?
Cane toad tadpole contain toxins (as do eggs, metamorphs and adults)
but I haven't seen any reports of bird deaths attributed to cane toad
tadpole consumption.
In lab experiments, some invertebrate predators have been observed to
consume toad tadpoles and die. Other invertebrate predators apparently
consume toad tadpoles without ill effect.
The tadpoles of some native frog species also have been observed, in
the lab, to consume (dead) toad tadpoles and die.
I believe I've seen reports of some fish species consuming toad tadpoles,
in the lab, and dying - but I can't remember the ref. Toad tadpoles are
unpalatable to some fish species and this unpalatability might
deter consumption by birds.
Some bird species, e.g. Black Kites, have been reported to consume
adult toads (at least partially) without ill effects so its plausible
that some bird species might be able to consume significant number of
toad tadpoles without ill effect.
I believe toad tadpoles can form large aggregations which might
increase the likelihood of a predator consuming a large number in a
short period.
Andrew Taylor
Birding-Aus is on the Web at
www.shc.melb.catholic.edu.au/home/birding/index.html
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