Yesterday morning I managed to get some images of the White-backed Swallows leaving their nest tunnel. The birds are tricky to catch actually entering the tunnels – they circle well above the site and then make a late dash.
I did however, capture a few exit moves – interestingly both of my decent shots had adults removing faecal pellets. Presumably there is an overnight build up from the nestling activity and this early morning chore is part of the regular pattern.
White-backed Swallows use their own and other birds’ nesting tunnels as overnight roosting shelters. They are also known to be one of a few Australian bird species that enter torpor during winter. This note by D.L. Serventy (based on observations by Mr. W. Gable of Perth) was made in the journal Emu in 1970.
‘In the winter of 1936, on a wet and cold grey day, I examined one of the banks and noticed the nesting entrance of the swallows. Out of curiosity I opened up the nest and removed the overlay. Instead of unearthing a normal nesting cavity containing the usual remains of last season’s nest I was intrigued to find not only a larger cavity than usual, but that it was occupied by a group of adult birds. They remained in a listless torpid state as I lifted each individual out from the cluster and placed it in my felt hat. They showed no indication of fear or attempted flight, but remained inert, nestling into each other as if to escape from the bleak winter’s day. There were some 16-20 birds in the cavity, completely filling my hat. I studied the birds for several minutes, passing my hand over them. I then returned them to the cavity and covered it up with a sheet of rusted iron on top of which I heaped some earth.’
We are in a state of summer torpor here at the moment, bracing for the first real onslaught of summer heat!
Reference: D.L. Serventy, Torpidity in the White-backed Swallow, Emu 70(1) 27 – 28, 1970 – published by the Royal Australian Ornithologists Union.