For the last three weeks or so between 30 & about 90 Welcome Swallows have been perching &, apparently, hawking for insects on & from the power line which crosses our valley. Mostly, they perch over our neighbour's pasture but occasionally they perch over our native vegetation & in a dead Casuarina on our property. This is the highest number of this species which I've seen anywhere & the three week old persistent presence of this population of Welcome Swallows is curious. To me, at least.
After watching this phenomenon for some time my hypothesis is that the insects are being born up our valley on persistent south easterly winds during the last three weeks or so from the two dams in our valley, both of which have held lots of water &, I would imagine, are providing a good insect breeding ground.
I'm wondering if anyone else has observed this sort of event in relation to Welcome Swallows or any other bird species.