In an interview with BBC Radio Solent, Mr Crowle said Willow had worked at the hospital, where pigeons were “the main culprits”, for around nine years.

“Probably over a thousand pigeons live on the site, creating around ten tonnes of droppings per year,” he said.

“In a hospital, it’s quite dangerous: you have patients whose immunity is visibly low.

“If they breathe in the dust from pigeon droppings, it can lead to pneumonia.”

He added that they were also “messing up the equipment on the roof”.

“The hospital has many air conditioning systems and fans that are very expensive to keep clean and sterile,” he said.

“So our job was to intervene and make the pigeons believe that birds of prey had taken up residence.”

He said initially they went five days a week, eight hours a day, with a team of birds.

Over time, the pigeons “realized this was not a safe place to nest” and their numbers began to decline after about three years.

“It’s a huge commitment,” Mr Crowle said.

“As soon as you stop, within six months, they will come back to nest everywhere.”