Researchers in New Guinea have identified two new bird species that have toxic feathers. The regent whistler and the rufous-naped bellbird were found to contain a toxic substance named Batrachotoxin (BTX) in their feathers and bodies.
This substance is better known from the skin of poison dart frogs. Poison dart frogs do not produce this substance –it comes from their diet of millipedes and other invertebrates and is secreted in their skin. The researchers suspect the birds also acquire BTX from their diet of beetles and other invertebrates.
BTX jams open ion channels in cell membrane, which stops nerves from functioning properly and the scientists were intrigued as to why the birds were able to tolerate it without being badly affected. They studied the structure of the birds’ ion channels and found the birds have mutations that change the shape of the ion channel so that the BTX does not bind to it as well as to normal ion channels, and therefore tends not to jam in them and prevent the ion channel from working properly. These mutations are similar, but not identical to mutations also found in poison dart frogs.
The researchers claim the mutations in birds and frogs are “a key adaptation to BTX tolerance and exploitation across vertebrates” and an example of convergent evolution to protect them from predators.
References: ScienceDaily 31 March 2023; Discover Wildlife 16 May 2023; Molecular Ecology 13 February 2023 doi: 10.1111/mec.16878
Editorial Comment: People may ask why would God make poisonous birds or fogs, as these cannot be described as “very good”. We need to understand the world we live in now is not the original very good world. The present is not the key to the past in biology any more than it is in geology.
To understand how these poisonous creatures came about we need a proper look at Biblical history. In the beginning birds and frogs were created to eat plants, and in the original very good world there would have been plenty nutritious plant foods to eat. After Noah’s flood the environment degenerated and many birds and animals resorted to eating insects and other invertebrates and chemicals from these would get concentrated in their skin and skin appendages, such as feathers in the case of birds, and skin glands in the case of frogs. The mutations that diminishes the effect of the BTX toxin enables the birds and frogs to survive on a diet of beetles and other invertebrates, but the mutations are not making them evolve into anything else.
Mutations and survival are real biological processes but they are reminders that the world is going downhill and becoming more hazardous, not evolving upwards into better things.
Creation Research News 30 May 2023
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