Spme-tailed Sicift to Weather Conditions. 751 



April IGtli. — A perfect morning, with a cloudless sky 

 and a light sea breeze. Spiue-tailed Swifts passed over the 

 shore-scrub at a low^ elevation, making somewhat to the west. 

 I remarked to the friend with whom I was walking, " There 

 are the Swifts, our fine weather will not last long.-'^ That 

 very night great cumulus clouds appeared in the eastern sky, 

 drifted gradually overhead, and brought a heavy downpour 

 of rain. 



April 15th. — On this day the Swifts were seen migrating, 

 passing to the north-west over the beach, at a height of 

 perhaps sixty or eighty feet; weather cold, showery, squally, 

 wiiid veering north-west to south-west. 



April 27th. — This afternoon the Swifts passed to the 

 north-west in a long straggling party, over the beach and 

 the sea, at a height of perhaps sixt}^ feet; wind south-westerly, 

 strong, cold. This was their last appearance, and the latest 

 date at which I have ever seen them ; I believe it constitutes 

 a record for Tasmania, and probably for Australasia. 



A reason may now be suggested for these appearances of 

 the Swift in the time of disturbed weather, and it is this. 

 The bird feeds largely upon ants in the winged state, and, 

 indeed, 1 believe such to be its favourite article of food; the 

 male and female ants having reached the winged state, fre- 

 quently issue in vast numbers from their nests during those 

 hot muggy days which precede a disturbance, while the so- 

 called "white ants'^ or termites, very tasty morsels, will often 

 " swarm " while a light warm rain is actually falling. It 

 seems highly probable, therefoi'c, that this Swift appears in 

 numbers in the vicinity of a weather-distuibance because its 

 favourite food is more jjlcntiful and more easily obtained at 

 such times. There may be other conditions of which at 

 present we know nothing, affecting the sudden appearances 

 and disappearances of tiiis most interesting species, but the 

 theory here advanced seems a reasonable one. I ho])e, 

 however, that other observers of our migratory birds may 

 be induced to give particular attention to the habits of tliis 

 fine Swift. 



