DERBY FLYCATCHER 95 



white, and they are sparingly marked with small spots and minute 

 dots, mostly about the larger end, of very dark browns, or almost 

 black, "seal brown" or "liver brown," and shades of "Quaker drab" 

 or lavender. The measurements of 50 eggs average 28.5 by 21.0 

 millimeters; the eggs showing the four extremes measure 31.4 b}- 

 21.8, 30.0 by 22.6, 25.6 by 22.4, and 30.9 by 18.8 millimeters. 



Plumages. — I have not seen any very young specimens, but birds 

 in full Juvenal plumage are much like the adults, the sexes being 

 alike; but the young birds have no yellow in the crown, the colors 

 generally are duller, the plumage is softer, and the rufous margins 

 of the wing coverts and secondaries are somewhat wider. This ju venal 

 plumage is worn through the summer and early fall, or until October 

 or even later, when a postjuvenal molt replaces the contour plumage 

 with a first winter plumage, which is practically adult. The juvenal 

 wings and tail are, however, retained until the following spring or 

 later. 



A complete postnuptial molt of adults occurs in August and Sep- 

 tember; but there is apparently only a very limited molt of the 

 contour feathers in the spring. 



Food. — Dickey and van Rossem (1938) write: "Stomachs of four 

 birds taken at San Salvador in 1912 contained small beetles, wasps, 

 and small grasshoppers in relative abundance in the order named,' 

 and, in addition, a mass of smaller-winged insects. At Puerto del 

 Triunfo many birds were seen perched on mangrove roots over the 

 water, sitting motionless and in their attitudes resembling king- 

 fishers. In striking the water, however, they do not make the clean- 

 cut dive of a kingfisher, but after hovering an instant make a headlong 

 splash. The objects of the dives seemed to be tiny fish. This was 

 certainly so in one case and by inference in others. This species is 

 one of the very few larger flycatchers which appears never to take 

 fruit or berries." 



Contradicting the last remark. Dr. Charles "VV. Richmond told 

 ^Major Bendire (1895) that he had "seen one specimen that had its 

 mouth and throat full of ripe banana." And William Beebe (1905) 

 says : "It was winter, and insects, while fairly abundant, were appar- 

 entlj^ too scarce to provide the flycatchers with their usual diet, and 

 we found them feeding freely on berries and seeds." 



The fishing habit has been observed by others. Dr. Beebe de- 

 scribes it as follows : "Like the kingfishers, the Derby perched upon a 

 rock and watched the eddies, and then dived with all his might two 

 or three times in succession, each time securing a small fish, or some- 

 times a tadpole. It seemed impossible for him to immerse himself 

 more than three consecutive times, for his })lumage became water- 

 soaked, and he then flew heavily to a sun-lit branch to spread himself 

 to the sun. After drying he was at it again." 



