Swallow entering her nest

Bethany and I took a walk around Strathaven Park today, weather wasn't good, showers most of the day, we wanted to play a game of golf ( well putting) but the rain cane down, so we went inside the tea room that's joined to the outdoor bowling green, she noticed a few swallows flying by the window, so after watching these for about 10 minutes, rain went off, we went outside to get a closer inspection and tried to locate the nests, I walked past it twice and on our way back out to the car, Bethany shouts.. Dad, look it's there and there's 3 nests together, so we moved a little out of the way so as to not distract them coming and going into their nests, I had to use my 70-300mm lens to get a closer shot, took about 20 shots and this was the best I could do, boy do they fly at super speeds, even going into and coming out of the nests! I was asking a old man how was standing at the outdoor bowling green's door, why the nests were painted white along with the walls, he told me these best had been there for many years? And rather than destroy them, each year when the building gets a lick of paint, so does the 3 nests, I'd like to think they've been there for as long as the building ( 1902) but Im sure they've not!