Do pigeon droppings corrode limestone buildings? You would think this question has been definitively solved, but it appears that at least by 2004, it hasn’t. No one doubts that pigeon (Columba livia) excrement is not only visually disgusting but also a potential source of disease and allergens. But it was unclear as to whether pigeon droppings corrode limestone, a common stone used in historic buildings.

Pigeon Dropping Research

An article by Miguel Gomez-Heras, David Benavente, Monica Alvarez de Buergo and Rafael Fort entitled, “Soluble salt minerals from pigeon droppings as potential contributors to the decay of stone based Cultural Heritage” published in the European Journal of Mineralogy (16:505-509) looked at whether accumulated pigeon droppings could be a source of salts and low pH that could damage limestone.

They investigated piles of pigeon droppings that were almost 12 inches deep that were not exposed to rain. Their samples included both dry and fresh droppings. They used the samples in two different tests. Test one sought to determine the droppings’ insoluble inorganic solids and salt content. The second test looked at the pH of the feces when mixed with water. They then used some of the liquid/material from the second test to apply to blocks of highly porous micritic limestone so that they could see what damage, if any occurred to the limestone.

Pigeon Droppings Corrode Limestone

Researchers found that when water mixes with pigeon droppings, the resulting liquid is not only acidic but very salty. These findings, say the researchers, contradict that of other researchers who argued that pigeon droppings had limited negative effects on building stones. The article’s authors contend that pigeon droppings are in fact a significant source of salts capable of damaging historical buildings as well as diminishing their visual beauty. What is interesting from the article was how salts and the crystals associated with them broke limestone grains thereby damaging the limestone’s integrity.

Bottom Line

Keep pigeon droppings away from limestone because the droppings will degrade the limestone.

Stephen M. Vantassel, CWCP, ACE, is the owner of Wildlife Control Consultant, LLC. He helps people restore their balance with nature through publishing, training, consulting, and the internet. He has published numerous articles in trade and academic publications available at {Stephen’s Academia.edu Page} along with several books {WCC Store}). Listen to his podcast “Living the Wild Life” at {Pest Geek Podcast}. Click the links for past {shows} and {interviews}. Please subscribe to {Stephen’s YouTube Channel} He is a sought after speaker and trainer. If you would like to have Stephen speak at your event or use his consultation services, send an e-mail to [email protected] Copyright All postings are the property of Stephen M. Vantassel and Wildlife Control Consultant, LLC. Text (not images) may be reprinted in non-profit publications provided that the author and website URL is included. If images wish to be used, explicit and written permission must be obtained from Wildlife Control Consultant, LLC.