A US Customs and Border Protection radio tower near the Texas-Mexico border is being disrupted by the poop and vomit from over 300 black vultures.

The tower has proved exceedingly popular with the scavenging birds of prey who have, for all intents and purposes, taken it — and the structures around it — hostage.

“[The birds] will often defecate and vomit from their roost onto buildings below that house employees and equipment,” a CBP spokesperson told Quartz. “There are anecdotes about birds dropping prey from a height of 300 feet, creating a terrifying and dangerous situation for those concerned.”

The tower itself is covered in layers of smelly, corrosive feces, urine, vomit and other droppings that eat away at the metal in the tower, making it unsafe for maintenance workers.

The birds have made the tower their home for almost six years, but the agency has been hampered in its desire to get rid of them due to the Migratory Bird Treaty Act which prohibits the killing of vultures. Violators face fines of up to $200,000 and a year in federal prison.

CPB is now looking into “netting” solutions to deter the birds.