NLsthig-Culomj of the Straiv-necked Ibis. 185 



XVI. — A Visit to a Nesting Colony of the Straw-necked Ibis. 

 By D. Le Souep, C.M.Z.S. (Melbourne). 



The Straw-necked Ibis {Carphibis spinicoUis) is found all 

 over Australia^ according to the season^ while it fiequeritly 

 congregates in vast numbers, for the purpose of nesting, in 

 some locality where there has been a sufticiently abundant 

 rainfall and where food is plentifid. 



Tlie colony of this Ibis which I propose to describe is 

 situated on the plains in the Riverina district, New South 

 Wales^ where a large swamp of about 600 acres has this 

 year [1900] been filled with rain-water to the depth of 

 3 feet for the first time since 1894. In 1896 this swamp 

 was partly full, and large numbers of Ibises came to breed 

 upon it, but about a fortnight after the eggs M'cre laid — the 

 -water in the meantime having dried u}) very i-apidly — all 

 the birds suddenly deserted their nests and left the district, 

 while in two days' time every egg had been eaten by Ravens 

 [Corvus austrulis). Tiie birds evidently changed their 

 quarters on account of the disappearance of the water, and 

 also probably on account of the failure of their food-supply, 

 as the season was not very favourable. This year the swamp 

 is quite full, and, after careful computation, I should estimate 

 the number of Ibises on it at somewhere about 200,000, 

 more likely above than below that estimate. It is curious 

 how these birds affect certain localities, while others that 

 seem to be equally suitable are untenanted ; but they 

 evidently prefer breeding in company, and have apparently 

 winged their way from all over the colony to this favoured 

 spot, where j,robably most of them had been hatched and 

 reared. In dry seasons, moreover, not a single individual 

 seems to be found anywhere in the district, but directly there 

 is an abundant rainfall thousands arrive. 



The swamp (see fig. 18, p. 186) is more or less covered 

 with dense lignum bushes, which the birds break and tread 

 down nntil they form a kind of platform from 6 to 18 inches 

 above the water. Then they build twig-nests about 2 inches 

 deep and 6 inches in diameter on the lignum. A few of the 



