n 1990 scientists preparing the skins of the hooded pitohui for museum collections experienced numbness and burning when handling them. It was reported in 1992 that this species and some other pitohuis contained a neurotoxin called homobatrachotoxin, a derivative of batrachotoxin, in their tissues. This made them the first documented poisonous birds,[15] other than some reports of coturnism caused by consuming quail (although toxicity in quails is unusual), and the first bird discovered with toxins in the skin.[16] The same toxin had previously been found only in Colombian poison dart frogs from the genus Phyllobates (family Dendrobatidae). The batrachotoxin family of compounds are the most toxic compounds by weight in nature,[17] being 250 times more toxic than strychnine.[18] Later research found that the hooded pitohui had other batrachotoxins in its skin, including batrachotoxinin-A cis-crotonate, batrachotoxinin-A and batrachotoxinin-A 3′-hydroxypentanoate.[19] Bioassays of their tissue found that the skins and feathers were the most toxic, the heart and liver less toxic, and the skeletal muscles the least toxic parts of the birds.[17] Of the feathers the toxin is most prevalent in those covering the breast and belly.[19] Microscopy has shown that the toxins are sequestered in the skin in organelles analogous to lamellar bodies and are secreted into the feathers.[20] The presence of the toxins in muscle, heart and liver shows that hooded pitohuis have a form of insensitivity to batrachotoxins.[17] A 65 g (2.3 oz) bird has been estimated to have up to 20 μg of toxins in its skin and up to 3 μg in its feathers.[15] This can vary dramatically geographically and by individual, and some have been collected with no detectable toxins.[19] The poisonous pitohuis, including the hooded pitohui, are not thought to create the toxic compound themselves but instead sequester them from their diet. Phyllo
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