Copycat Birds

Genetic studies suggest that one of New Guinea's poisonous birds may be mimicking a toxic neighbor.

When it comes to warning signs, nature is a lot like the highway - many plants and animals use bright, distinctive color patterns to send messages like "Stop" and "Do Not Enter." These boldly colored species often make poisonous or distasteful meals, so predators eventually learn to avoid eating them. When two toxic species display distinct color patterns, potential predators must learn to pass up multiple types of pretty packaging. However, if both species use the same warning sign, they can share the job of teaching their predators to stay away. Because of this, many poisonous plants and animals have evolved to resemble their toxic neighbors - a process called Müllerian mimicry. Until recently, this type of mimicry was not known among birds, but Academy ornithologist Jack Dumbacher may have found the first such case while studying the poisonous pitohuis of New Guinea.

In 1989, Dumbacher discovered that some of New Guinea's pitohuis carry a neurotoxin in their feathers and skin - the same toxin secreted by Colombia's poison-dart frogs. Since then, he has been working to understand the ecology and evolutionary history of these colorful songbirds. Among the six species in the Pitohui genus, one of the most poisonous, Pitohui dichrous, has "warning sign" coloration composed of a brick-red belly and back against a jet-black body. Dumbacher's molecular studies have shown that one neighboring bird - a subspecies from the poisonous P. kirhocephalus species - has evolved a matching color pattern, suggesting the presence of Müllerian mimicry.

Rope bridge over the Fio River, one of the research sites near Herowana. Photo: Jack Dumbacher
 

 

Top photos: Hooded pitohuis. Lower left: A mimetic variable pitohui from Herowana Village in Eastern Highlands Province. Lower right: A mimetic variable pitohui from Kakoro in southern watershed of Papua New Guinea.
All photos by Jack Dumbacher

Jack Dumbacher at work in the rainforestof Papua New Guinea. Photo: Ramona Gaylord

Budding New Guinea naturalists curious to try out our binoculars and see the birds we are studying.
Photo: Jack Dumbacher