I was watching for a food delivery at the edmonton clinical sciences location and noted that the adults seem to be unruffled by the helicopter landing a few metres away on the hospital roof, plus hot air balloons passing directly overhead and very close to roof level. I am amazed at their level of tolerance. It obviously hasn't affected the peregrines, given the nesting success here.
Its not so much that they become tolerant of noise in general, rather they become accustomed/tolerant of noises that have become familiar and which they have deemed not to be a threat. Radisson is the resident female at the U of A and she hatched out of the nestbox we are now watching on the FalconCam. The Radisson roof is noisy with both natural sound like the wind howling through the louvres (I have a audio clip of that, will find it and post it in our video gallery) as well as street noises like traffic, construction, sirens as well as regular noises on the roof due to maintenance done by staff. All of those they assess the risk of/for and then later recognize and acknowledge them without immediately leaping into action.
That was one of the problems out at the 2007-2009 West Winnipeg flight, the sounds were irregular and very close and so the birds spent more time defending than nesting. Not the site's fault, just a poor choice by Jules & Ivy. Where Jules and Beau are now is much less "active" so they can concentrate on what is important. The ultimate in noise was a pair that nested beside the St Boniface Basilica bell, only did it once, but I dare say it took some getting used to the bell ringing every 1/2 hour or so.
Now having said all that, when there is a "new" noise at the Radisson, both Princess and Ivy (and previously Pop, Maud, T-Rex, Madame, Simba & Trey) all knew it within seconds and one if not both of the resident pair would be checking it out. For them, there is noise they know and noise they don't trust. Two young men were working daily on the roof of the Radisson this year to rebuild a large chiller unit and Princess and Ivy just watched, then ignored them. Some noise for the first couple of days, then nothing. I turn up on the roof and within seconds I'm getting the third degree, you'd think they didn't trust me!
