Do you know that a bird can be poisonous? But it's true. The presence of venom in snakes, scorpions, some species of frogs and lizards, like the Komodo monitor lizard, can be explained, and even platypuses have it, but birds ... Currently, it is known about six species of thrush flycatchers (lat.Pitohui) living in Papua New Guinea ... Omnivorous, brightly colored birds are endemic to the island and feed on a particular type of beetle believed to be the source of a powerful neurotoxin. In particular, the skin and feathers of the bicolor blackbird flycatcher (bicolor pytochu) are the main source of the toxin.
These amazing birds with orange and black feathers are the only birds among 9,200 bird species whose plumage, skin and flesh are riddled with batrachotoxin, which is hundreds of times more toxic than strychnine.
In 1989, during a study by biologists from the National Institutes of Health in Bethesda, Maryland, and the Smithsonian Institution in Washington, DC, led by ornithologist Jack Dumbacher of the University of Chicago, a toxin was found in this bird that causes burning, numbness and sneezing. For this reason, the local population avoids these birds and does not use them for food, they call them "trash birds". But in hard times, the natives eat these birds, but first get rid of their skin and feathers, and everything else is well baked in coals.
The discovery of the thrush flytrap toxin
Jack Dumbacher came across the secret of blackbird flycatchers by accident. In 1989, he and his team arrived in Papua New Guinea to study the Raggiana Paradise bird of paradise, they set up nets to catch and study it properly. However, many other birds were caught in the net, as well as several thrush flycatchers. When he tried to free these birds, he was attacked, they scratched him a little. He felt incredible pain in his hands and a strange tingling sensation. He put his hands in his mouth to relieve the burning sensation, but he felt a tingling sensation on his lips and tongue. He began to understand what had happened and decided to take a pen to test his hypothesis. They found that there is actually a toxin in the feathers that comes from beetles of the Melirid family, Choresine pulchra. Locals used this toxin for hunting, which in large enough doses can cause paralysis and even death, especially in small animals. It begins to disrupt the sodium balance in the nerve cells, the muscles begin to contract involuntarily. Even small doses lead to paralysis of the limbs, impaired locomotion and prostration.
A photo. Bicolor blackbird flycatcher (Pitohui dichrous)
In Papua New Guinea, only three species of birds belonging to the genus of blackbird flycatchers have this toxin found in their skin and feathers. These three toxic birds have been identified as the bicolor thrush flycatcher (Pitohui dichrous), the red-headed blackbird flycatcher (Pitohui ferrugineus), and the choppy thrush flycatcher (Pitohui kirhocephalus). Of all three species, it is the bicolor thrush flycatcher that is considered the most toxic. Dumbacher and his colleagues took samples from these birds, including skin, striated muscles, feathers, and stomach contents.
From the samples, the toxin was separated from other substances. It was then that the researchers observed batrachotoxin. This poison, a steroidal alkaloid, is very similar to that found in the poison dart frogs of Central and South America, and whose skins Colombians use to make poison and spread it on darts and arrows.
The toxicity of the venom of thrush flycatchers was tested by subcutaneous injection into the tissues of the extremities of laboratory mice. Depending on the dose, the toxin in mice caused partial or complete loss of performance of the musculoskeletal system, convulsions, and even death. The found toxin activated sodium channels in cells, interfering with the resistance of cell membranes. Skin and feathers were found to be the most toxic of all tissues tested, while tissue tests of the bicolor thrush flycatcher showed the highest toxicity among the three species of thrush flycatchers.
A photo. Choresine pulchra beetle eaten by the blackbird flycatcher
Biologists have concluded that the toxin serves to protect blackbird flycatchers from natural predators, including snakes and some marsupials. This conclusion was the basis for the fact that it is now widely accepted in the ornithological environment that the blackbird flycatchers are the first documented venomous representatives of the class of birds (Latin Aves), warm-blooded vertebrates. Blackbird flycatchers also have two other characteristics: they are brightly colored in a contrasting orange-brown or black color, and they give off a strong rancid odor. These two factors make thrush flycatchers highly undesirable hunting targets among roving predators.
Thrushcatcher Toxin Poisoning Incidents
Official statistics are silent about this. One can only assume that cases of poisoning occurred and possibly even led to death, which the local residents could take advantage of, because cannibalism still flourishes there. But this is of course a joke, but with a subtle hint.
Birds have learned not only to be poisonous, but also to imitate other poisonous representatives of the animal world. This is especially useful for chicks that are most vulnerable to predators when their parents are away.
Amazonian bird chicks mimic venomous caterpillars
The chicks of one Amazonian bird called the gray aulia (Latin Laniocera hypopyrra) mimic the toxic hairy caterpillars of the flannel moth in both appearance and behavior, according to a team of bird watchers led by Dr. Gustavo Londogno of the University of California, Riverside.
In 1817, French scientist Louis Jean Pierre Vieillot discovered the gray aulia, which is a species of passerine birds of the Tityridae family. These birds are often found throughout much of the Amazon. She has black eyes with a narrow orange gap, dark gray legs, a rounded head and looks a bit like a dove. Adults, as a rule, reach from 20 to 21 cm in length, weight reaches 41-51 g.
The bird in general is unusual and it is a rather inconspicuous inhabitant of the forest. It lives relatively in high-mountain forests, but also lives in seasonally flooded swampy forests, as well as in wet sandy-wooded areas, wooded savannah and wooded sandy ridges.
A photo. Gray aulia chick (Latin Laniocera hypopyrra) and a poisonous caterpillar from the megalopygida family
In the fall of 2012, in southeastern Peru, during a long-term avian survey, Dr. Londoño and his colleagues saw an extremely rare gray aulia nest. They noted that the hatched chicks had down feathers with long orange barbs ending in white tips that were very different from any other chick observed in the area. The peculiar downy feathers caught their attention, but the behavior of the chicks gave a more important signal.
While the ornithologists were taking morphological measurements, the chicks began to move their heads very slowly from side to side, which is very characteristic of many hairy caterpillars.
While working in the area, they also found poisonous caterpillars of the flannel moth (family megalopygida) with the same size and hair coloration as these chicks. In an article in the American Naturalist magazine, they suggested that this is an example of Bates' mimicry, in which the chick mimics a poisonous prickly caterpillar, ostensibly saying that it is not edible and even dangerous.
"Although there is little evidence of Bates mimicry in birds, there are examples of warning coloration," the scientists report in their paper. “In particular, the bicolored blackbird flycatcher has aposematic plumage (orange and black) and contains toxins. It is likely that gray awliya chicks contain toxins, in which case they will best characterize Müllerian mimicry. However, we believe that this is unlikely. "
This entry was posted on Tuesday, January 31st, 2017 - 04:54 PM. You can leave a comment.