Warning signs in a poisonous Papuan songbird

SEPTEMBER 10, 2019

by Casey Mcgrath, Society for Molecular Biology and Evolution

Bright colors and conspicuous markings are often used in nature to warn off would-be predators. While we are used to seeing such markings—termed aposematic signals—in plants, caterpillars and snakes, we do not usually think of colorful bird plumage as conveying the same message. However, members of the New Guinea songbird genus Pitohui use their plumage to warn predators that they are toxic.

Aposematic coloration often gives rise to so-called Müllerian mimicry rings, in which multiple toxic species evolve to resemble each other, as a mutual form of protection. The theory is that predators will more quickly learn to avoid all of the species in the ring, with less of a cost to each species. While these rings are common in butterflies and other insects, they are less common among vertebrates where the genetic basis of these traits is often unknown. This is certainly true for pitohuis, one of the few toxic birds on Earth. In a new article in Genome Biology and Evolution titled "Gene flow in the Müllerian mimicry ring of a poisonous Papuan songbird clade (Pitohui; Aves)," an international team of researchers from the National University of Singapore, Biology Centre CAS in the Czech Republic, and the New Guinea Binatang Research Centre set out to unravel the genetic basis and evolutionary history of pitohuis' colorful plumage.

Read on

Feather-munching bacteria damage wild bird plumage

Date:July 13, 2016

Source:Central Ornithology Publication Office

A new study in The Auk: Ornithological Advanceslinks feather-degrading bacteria to damaged plumage on wild birds for the first time, offering new insights into how birds' ecology and behavior might affect their exposure to these little-studied microbes.

Scientists know surprisingly little about the diverse community of microbes that lives on bird feathers. A few of these species of bacteria can actually break down keratin, the material feathers are made of, but few studies have looked at how feather-degrading bacteria actually affect birds in the wild. Combining data from a decade's worth of bird-banding studies, Cody Kent and Edward H. Burtt of Ohio Wesleyan University found that tail-feather wear was strongly correlated with the presence of feather-degrading bacteria -- the first time this relationship has been demonstrated in live, wild birds.

Kent and Burtt's dataset included more than 3,500 birds from 154 different species captured between 1996 and 2005, in locations ranging from a rural Ohio backyard to Canada's Bay of Fundy to a Louisiana bayou. Researchers carefully wiped each bird's plumage across petri dishes containing a growth medium to culture any microorganisms living in the feathers. Ground-foraging, aerial-foraging, and fly-catching birds had a higher prevalence of feather-degrading bacteria, while nectivorous, tree-probing, and marine-foraging birds were less likely to harbor the microbes.

Read on ...