108 BIRDS OF AUSTRALIA. 



is hailed as a welcome indication of the approach of spring, 

 and is associated with precisely the same ideas as those 

 popularly entertained respecting our own pretty Swallow in 

 England. The two species are in fact beautiful representatives 

 of each other, and assimilate not only in their migratory 

 movements, but also most closely in their whole habits, 

 actions, and economy. It arrives in Tasmania about the 

 middle or end of September, and, after rearing at least two 

 broods, departs again northwards in March ; but it is evident 

 that the migratory movement of the Swallow, and doubtless 

 that of all other birds, is regulated entirely by the temperature, 

 and the more or less abundant supply of food necessary for 

 its existence ; for I found that in New South Wales, and 

 every country in Australia within the same latitude, it arrived 

 much earlier and departed considerably later than in Tasmania ; 

 and Mr. Caley, who resided in New South Wales for several 

 years, and whose valuable notes on the birds of that part of 

 the country have been so often quoted, states that " the 

 earliest period of the year that I noticed the appearance of 

 Swalloivs was on the 12th of July 1803, when I saw two ; but 

 I remarked several towards the end of the same month in the 

 following year (1804). The latest period I observed them 

 was on the 30th of May 1806, when a number of them were 

 twittering and flying high in the air. When I missed them 

 at Paramatta, I have sometimes met with them among the 

 north rocks, a romantic spot about two miles to the northward 

 of the former place." A few stragglers remain in New South 

 Wales during the winter, but their numbers cannot for a 

 moment be compared with those observed in the summer, 

 which have passed the colder months in a warmer climate. 

 This Swallow having been found by the naturalists of the 

 * Astrolabe ' in the Eastern Islands, and more recently by 

 Mr. Wallace in New Guinea, it is evident that its range 

 extends beyond the northern limits of Australia. 



The natural breeding-places of this bird are the deep clefts 



