4 healthy (not so happy) falcon chicks banded at the Hamilton Sheraton

A cacophony of high-pitched shrieks echoed through the 17th floor of the downtown Hamilton Sheraton Hotel Thursday, as four new baby falcon chicks were examined and banded before they leave the nest.

This marks the 24th year the same nest site high on the side of the hotel is being used by a mating pair of Peregrine Falcons — a species that was once on the brink of extinction, but is now in recovery. 

The city's resident adult pair, Lily and Ossie, have been in Hamilton for three years now, with this marking their fourth nesting season. The Ministry of Natural Resources and Forestry, in partnership with the Hamilton Community Peregrine Project, puts identifying bands on the chicks so they can keep track of the growth and spread of the species. 

That way they'll know how many chicks live in each nest, where they end up, and if they survive. The birds are taken from the nest while the tests and banding happen, then returned.

The four male chicks were all tagged and named: Lawrence, Ainslie, Gage and Lisgar — with their namesakes all coming from area parks.

As they were all weighed, tagged and banded before having blood tests done, it sounded a little bit like four miniature car alarms going off.

"Sometimes it's not an easy go around with Peregrines on your house," sad Mark Nash, of the Canadian Peregrine Foundation.

While the chicks were being examined, their parents were relentlessly circling the nest just outside, which was being occupied by climber Chris Phinney from the city's public works department, who had nabbed the birds so they could be taken inside.

Phinney then had to sit perched on the ledge with the nest, anchored to the face of the hotel itself with rope and climbing gear to prevent the parents from returning while the chicks are away.

"Mom and dad are obviously not happy about this entire process," Nash said. "This doesn't come without risks. Some of these birds can be extraordinarily aggressive."

In recent years, some climbers who were helping with banding efforts have ended up with multiple stiches from falcon talons, as the dive-bomb nests in an effort to protect their babies.

There's even a fear of West Nile virus transmission. The falcons themselves don't carry the virus, but it can be found in carrion left on their claws.

"You wouldn't catch me out there doing it," Nash said.

This year's large brood is a rebound for the pair after they failed to hatch any chicks last year and just one in 2016.

Lily was banded in 2010 at the Grand Haven Board of Light & Power plant in Michigan, and Ossie left from the Osler Hospital in Etobicoke in 2012.

The pair produced several eggs last year, but none hatched.