Feces of birds defy expectations

Uric acid seems to be the solution.

Why are bird feces so difficult to remove from buildings? Uric acid.

Why are they white and pasty? Uric acid.

Why are they corrosive to automotive paint and metal structures? Uric acid.

These responses are based on the prevailing wisdom that uric acid is the main ingredient in "poo" of birds, consisting mainly of urine. (Birds release solid and liquid waste at the same time, white matter is urine).

But according to Nick Crouch, a scientist at the University of Texas at Austin, uric acid can not be the answer. This is because there is no uric acid in the urine of the excreted bird.

And after analyzing the excretions of six different bird species, from the Great Horned owl to the humble chicken, it is rather positive of this statement.

"It was easy to say that what we had and that it was not uric acid," Crouch said.

The results were published in the Ornithology journal in August 2019. The co-authors of the study are Julia Clarke, a professor at the Jackson School of Geosciences, where Crouch is currently a postdoctoral researcher, and Vincent Lynch, a chemist and researcher at the UT College of Natural Science.

Crouch studies the evolution of poultry and biodiversity. The waste chemistry of birds is not his usual search hitch. However, Crouch decided to study the issue of uric acid after a conversation in 2018 with the late Jackson School's teacher, Bob Folk, who claimed that the bird waste did not contain any trace of it. Uric acid.

"Sometimes you are just asked a really strange question and you want to know the answer," said Crouch. "That was it, I did not know if [Folk] was right or wrong in advance, but I was really interested to take a look. "

Folk had examined the question himself in the 1960s and had found no sign of the substance in samples taken from 17 species.

"Bob Folk was a creative and ambitious scientist who was primarily interested in rocks," Clarke said. "It's a proof of his boundless creativity that he adopted what he called his" paper bird ""

Folk published an article in 1969 describing the X-ray diffraction pattern and the solubility tests that formed his analysis. But his work was challenged by a 1971 article that found evidence of uric acid in Budgies waste, a type of parrot, using the same type of X-ray diffraction analysis used by Folk.

Crouch said he thought resuming analyzes using modern technology could help solve the problem. Although X-ray diffraction has not changed much in the last 50 years, the technology of analyzing its results, which consists of distinct scattering patterns created when X-rays are diverted by different chemicals in a substance, has become much more precise and precise. accessible over the decades.

As for the samples themselves, most came from birds raised at the Austin Zoo, while the sample of chicken waste came from a herd belonging to the court belonging to Crouch's neighbors. Overall, the samples covered a good deal of bird diversity, including species belonging to the three major groups of birds, a variety of diets and species unable to fly. But none of the samples produced X-ray diffraction pattern compatible with uric acid. The analysis revealed ammonium urate, struvite and two unknown compounds.

Crouch explained, according to findings of other research, that these substances are probably due to bacteria present in the bird's intestine, which break down uric acid before that it is not excreted. Research by other scientists has identified a wide range of bacteria inside the digestive organs of birds.

Sushma Reddy, Associate Professor and Breckenridge Chair in Ornithology at the University of Minnesota, said she was surprised at the results of the research and thinks that she will encourage more research on the subject. physiology of birds.

"This goes against the old doctrine we are learning," Reddy said. "It's pretty amazing to live at this time, where we can reanalyze with incredible technologies those things we took for granted."

Crouch said that this research opens the door to new research questions, ranging from the power of the bird microbiome to the identification of two unknown substances. He said that more than anything, it shows the value of taking the time to question conventional wisdom.

"I did not know I was going to work on the bird pee," said Crouch, "but I find myself faced with many new questions about the avian microbiome, which shows that our research can lead us into unexpected and exciting directions. "