Dear All,
No doubt most B-A members have read about birds succumbing to Cane
Toads after they have eaten them. Researchers have come across birds
that would possibly have the same effect on the toads, or anything
else that may eat them. A paper in "The Auk" (July 2009, Vol. 126, No.
3) explains. The abstract of the paper says:
"Several bird species in the endemic New Guinean genus Pitohui contain
potent defensive toxins of the batrachotoxin family of steroidal
alkaloid neurotoxins. We surveyed toxin concentrations in various
tissues of Hooded Pitohui (Pitohui dichrous) using radioligand binding
assays. The highest concentrations were found in the skin and
feathers, on the outside of the birds, where predators or parasites
are likely to encounter toxins. Significant levels of toxins also were
found in skeletal muscle, heart, and liver. Muscle and liver would
normally be poisoned by batrachotoxins; thus, Hooded Pitohuis must be
insensitive to the toxins. The presence of toxins in internal organs
further argues against the hypothesis that Hooded Pitohuis merely
apply toxins topically to skin and feathers. Finally, we used scanning
and transmission electron microscopy to examine skin and feathers for
unusual morphological or histological adaptations for storing and
secreting toxins. The skin of Hooded Pitohuis appears to have typical
dermal and epidermal morphology, and we speculate on possible ways in
which this species may sequester and secrete toxins using typical
avian skin structural features, unique among vertebrates." The
complete paper can be downloaded from http://caliber.ucpress.net/doi/abs/10.1525/auk.2009.08230
The Genus name, Pitohui, probably came from the noise one would make
if you were to eat one. Does anyone out there know of any other toxic
bird species?
Cheers,
Carl Clifford
===============================
www.birding-aus.org
birding-aus.blogspot.com
To unsubscribe from this mailing list,
send the message:
unsubscribe
(in the body of the message, with no Subject line)
to:
===============================
|
