Swifts leaving a nestbox

This is a short video of six of our swift boxes, high on the side of our house. Watch the left hand box - about 20 seconds in, you'll see a swift flying out of it. Blink and you'll miss it. This pair occupied the nest within three weeks of us putting up the boxes. This is unusual. It's probably because this pair have been displaced from where they were already nesting last season or were planning to nest this season. It may also be because we played swift calls from dawn until dusk straight up into the sky from those orange speakers you can see just above the middle two boxes!