SOUTHERN AMERICAN REDSTART 673 



also located in a shrub near a house, that was quite probably 

 destroyed by one. However, since the vast majority of redstarts 

 build in locations remote from human habitations, cats are not an 

 important factor in affecting the redstart population as a whole. 



John and James M. Macoun (1909) cite a case of a redstart's nest, 

 built in an exposed position, that was presumably destroyed by an 

 olive-sided flycatcher that had a nest on an overhanging branch a 

 few rods away. 



C. H. Morrell (1899) states that two redstart nests which he ob- 

 served were deserted after the eggs had been laid because caterpillars 

 had taken possession of the nesting tree and had completely overrun 

 the nests. E. H. Forbush (1907) in connection with a gipsy moth 

 infestation at Medf ord, Mass., writes : "There was a nest of the Ameri- 

 can redstart and the tree had been stripped of leaves by the caterpil- 

 lars. There were four young in the nest. I saw the old birds take 

 but one very small gipsy moth caterpillar to the young, but they 

 would pick the large ones off the nest and drop them to the ground 

 very often. There were no pupae near the nest that I could see." 

 Mr. Forbush does not state whether the redstarts succeeded in winning 

 their fight against this caterpillar infestation. 



Louis Sturm (1945) says that one nest that he observed "was robbed 

 by a small fox snake {Elaphe vulpina gloydi) which had swallowed 

 all three eggs when discovered coiled in the nest." 



The redstart, like most birds, is host to a number of external para- 

 sites, of which Harold S. Peters (1936) has identified the three species 

 of lice Menacanthus sp., Myrsidea incerta (Kellogg), and Philopterus 

 subflavescens (Geoffroy) and the tick Haema'phy sails leporis-palus- 

 tris Packard. 



Perhaps the greatest menace to the redstart is the parasitic cowbird, 

 of which this warbler is one of the commonest victims. According to 

 Herbert Friedmann (1929) at Ithaca, N. Y., the redstart was the most 

 imposed upon species. Out of 34 nests he found 23 of them contained 

 one or more of the parasitic eggs and it was not uncommon to find 

 sets composed of but one or two of the rightful eggs, the rest being the 

 cowbird's. 



Occasionally the redstart builds a new floor over the cowbird's eggs, 

 as is often done by the yellow warbler. This procedure is especially 

 likely to take place if the cowbird succeeds in laying its eggs before the 

 redstart's eggs are present. More often the redstart does not seem to 

 be amioyed by the strange eggs but goes on laying its own. It is 

 unusual for the redstart to desert its nest because of the presence of 

 cowbird's eggs. 



A nest was found on June 9, 1922, with two young cowbirds 5 days 

 old, completely filling and covering the nest. In the bottom beneath 



