INDIGO BUNTING 99 



storm off the Florida Keys. Thomas Barbour (1923) says that in 

 Cuba, "A very considerable number are often on sale in the bird 

 stores, and they are great favorites as cage-birds and apparently 

 thrive." 



William Brewster (1906) includes the indigo bunting among the 

 species "whose local decrease is probably due chiefly to persecution 

 by the House Sparrows." Some birds, he says, ceased breeding 

 "within ten years from the first appearance of the House Sparrows. 

 The Indigo-birds and Least Flycatchers disappeared more slowly, but 

 in the end almost as completely." An additional factor of impor- 

 tance evidently unassessed by Brewster was the change in habitat 

 and flora resulting from the industrial and residential growth of the 

 region. In any event, with the house sparrow becoming more and 

 more restricted at the present time to closely built-up sections, in 

 New England at least, the importance of that species as an enemy 

 appears to be comparatively small. 



The proximity of the nest of this species to the ground suggests 

 that it may be especially vulnerable to snakes and other wandering 

 marauders. In fact, H. Lewis Batts, Jr. (1958), gives this vivid ac- 

 count: "On June 18, 1949, a cat pounced upon a nest containing three 

 young Indigo Buntings and one pipped Cowbird egg, ate one young, 

 and carried away the others * * *." 



It is somewhat difficult to assess completely the effects of weather 

 on this species, but Johnston (MS.) and Bill Colson found two nests 

 in north central Florida, each containing two cold wet eggs, probably 

 the result of recent heavy rains. Additional mortality factors are 

 suggested by Phillips (1951): young killed by direct sunlight on the 

 nest and nest abandonment after having been found by humans. 

 Tall TV towers in recent years have accounted for deaths of many 

 migrating birds. For example, at a tower in Leon County, Fla., 

 between 1955 and 1961, Stoddard (1962) counted 345 indigo bimtings 

 killed, most of these in the autumn. TV towers, tall buildings, and 

 airport ceilometers throughout the eastern United States caused the 

 deaths of 450 indigo buntings between October 5-8, 1954 (Johnston 

 and Haines, 1957). 



Field marks. — The indigo bunting approximates the chipping spar- 

 row in size, being noticeably smaller than both song and house spar- 

 rows. The adult male in breeding plumage is the only small North 

 American finch that appears blue all over. It could be confused with 

 the male blue grosbeak, but the latter is a much larger bird, has 

 brown wing-bars, and a noticeably heavier bill. Under certain light 

 conditions, indigos may appear to be black or blue-green. Males in 

 their first nuptial plumage may not be entirely blue; they may retain 

 varying amounts of brown body feathers among the bluish ones and 



646-737— 68— pt. 1 9 



