Are there poisonous birds?

The bicolor pitohui or hooded pitohui ( Pitohui dichrous ) was the first poisonous bird officially documented in scientific literature. The toxic substance secreted by this pigeon-sized bird with a brick-red belly and jet-black head is concentrated in the bird’s feathers and skin. Many of these birds live discreet and elusive lives. Some have been dangerous to humans in the past, but thanks to modern science , we know a little more about these feathered creatures.

What is your poison?

Homobatrachotoxin is a neurotoxin present in the skin and plumage of these birds that induce numbness and tingling in those who come in contact with it, it is what makes the skin and feathers of these birds toxic. According to analyses, the toxic venom is most abundant in the feathers that protect the chest and abdomen , making this animal one of the most toxic birds in nature.

Most of their poison is derived from their diet. Because it is not the same toxic as poisonous. It is the same type of poison that we can find in the poison dart frogs of Colombia, so the poison that it secretes comes, most likely from the beetles that they eat (as in the case of the Choresine beetle of the Melyridae family). These substances are batrachotoxins or potent neurotoxic steroidal alkaloids. In high enough doses, such toxins can cause paralysis and death.

These birds are omnivores, so they eat both plant and animal foods (berries, insects…) The newborns do not have any toxins in their bodies and develop them gradually after growing up.

And how come they don’t poison themselves?

These birds, with sharp claws on their black feet and a strong black beak, often have a specific protein that absorbs toxins before they can harm the animal. Called “toxic sponges”, they protect birds from any toxic effects and allow the poison to remain on their feathers, skin or tissue without harming them.

The bright colors of the hooded pitohui, along with a strong odor it emits, are thought to be aposematic or intended to ward off predators. Since the venom is more concentrated in the feathers, it is likely intended to deter parasites such as lice and ticks.

Conservation status according to the IUCN (International Union for Conservation of Nature): minor concern. The population trend is stable and they are quite common in their hometowns, the rainforests of New Guinea.

Examples of toxic birds have appeared in all bird taxa, indicating convergent evolution. This means that poisonous birds are not all of the same genus or family.

Other poisonous species:

The ifrita (Ifrita kowaldi) or “bitter bird”, which carries the same toxins as neotropical frogs.

The common quail (Coturnix coturnix) , which while there has been some debate about the origin of the poison, current theories suggest that the quail eat the toxic seeds of the mint plant Slachys annua.

The spurred goose (Plectropterus gambensis) which integrates the chemical of the blister beetle; the toxin in question is the terpenoid compound cantharidin.

The common bronze pigeon ( Phaps chalcoptera ), whose fluoroacetate venom acts as an inhibitor of cellular respiration, causing a series of responses ranging from intense stomach pain to death.

The grouse grouse ( Bonasa umbellus) which, during the winter, feeds on mountain laurel buds that contain the chemicals andromedotoxin and arbutin. Toxic to mammals, they do not appear to affect capercaillie.

The Little Picanzo (Colluricincla megarhyncha) ; the chemical batrachotoxin is again the culprit, probably from the same insect or plant food source that the pitohui eats.

Referencia: BARTRAM, S. AND BOLAND, W. (2001), Chemistry and Ecology of Toxic Birds. ChemBioChem, 2: 809-811.

DUMBACHER, J.P., WAKO, A., DERRICKSON, S.R., SAMUELSON, A., SPANDE, T.F., DALY, J.W., (2004). Melyrid beetles (Choresine): A putative source for the batrachotoxin alkaloids found in poison-dart frogs and toxic passerine birds. Proceedings of the National Academy of Sciences Nov 2004, 101 (45) 15857-15860.

WELDON, P., (2000). Avian chemical defense: Toxic birds not of a feather. Proceedins of the National Academy of Sciences of the USA. Nov 21;  97 (24): 12948–12949.