Dusky and White-Browed Woodswallows - could they be nesting?

[jude hopwood <>]

After reading Robin's email about the Campbell Park Woodswallows, I wondered if the large mixed flock that has been busy at our place for the past two weeks would be doing the same? We have never sighted WBWS here before, nor anywhere for that matter, (nor Tree Martins until this morning) and since the very cold Sunday a few weeks ago we've been inundated. 

They all seem to love the fruit on the crabapples, but I've not seen them carrying any a long distance.  They are quite confident around both human and dog, but if a little close, grab the fruit and carry it to another tree nearby.  They do not appear to be carrying it a distance to a nest.  If they were, I can see from Robin's lovely photos how they nest, but just where should I look for them? Quick movers, aren't they!

Jude