264 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1954 



SUMMARY OF SOUTH AMERICAN DATA 



Probably no one has done more, or even as much, work with the 

 cattle egret in South America as Haversclmiidt. His published find- 

 ings have evidenced wide knowledge of, and great interest in, the 

 species, and it might be well here to redigest his opinions and con- 

 clusions. 



From the bird's sudden appearance in British Guiana in 1930 and its 

 subsequent occurrence in the countries of Surinam, Venezuela, Colom- 

 bia, Bolivia, and the Netherlands West Indies, the explanation of its 

 actual origin remains unknown. Haverschmidt (Auk, vol. 67, p. 381, 

 1950) suggests three possibilities: 



1. The bird was always indigenous but was overlooked. 



2. Birds comprising the present population are descendants of 

 escaped birds. 



3. Some birds somehow found their way to South America from 

 Africa and, the area where thej landed being suitable to their needs, 

 settled there and increased. 



He considers Nos. 1 and 2 extremely unlikely and believes that No. 

 3 is the solution. I agree completely. Such behavior has been char- 

 acterized as "explosive migi-ation." Considering the bird's spread 

 in Africa and to Australia, to say nothing of its normal tendency to 

 wander widely, this expression seems appropriate. A good illustra- 

 tion of it would be the result of liberation from the Wliipsnade Zoo 

 and the subsequent appearance of cattle egrets as far off as Iceland. 



The greatest number of birds checked at one observation was Haver- 

 schmidt's count of 1,112 at the Nickerie River roost. One of the most 

 surprising statements in all his publications of the bird appeared on 

 page 204 of the September-October issue of Audubon Magazine (1953) 

 in which he says : 



It is . . . highly unsatisfactory to be aware that the bird has been present 

 in South America for more than 20 years, yet there is not a single breeding 

 record for it in any of the countries where it now regularly occurs. 



He goes on to say that he has never found it in any regular heron 

 rookery and that it is not a bird of the mangroves or coastal mud flats. 

 Further, that "The nesting places of the cattle egret must be sought 

 in some inland and freshwater marsh." He assumes that the breeding 

 season is from April until July. (See below, in connection with the 

 North American nesting which, in all details, corroborates Haver- 

 schmidt's conclusions.) He concludes his illuminating account by 

 saying that he never saw a cattle egret on the back of a cow and he 

 doubts that it ever takes "ticks" from the skin of cattle. (See under 

 Behavior, below, regarding observations in Florida.) 



