May, 1911 
107 
FROM riFLD AND STUDY 
Remarks on the Food of Young Cowbirds. — To the writer the speculation has been in- 
teresting as to whether young Cowbirds nuist make shift to live and grow on diets varying 
widel}' according to the foster parents. An effort has been made to collect material bearing on 
the problem, Imt with little success. The vicinity of Washington is a poor place for Cowbirds. 
However 14 stomachs from other localities have been examined. The distril^ution among foster 
parents is as follows: Icterus galbida 1, Pooecetes gramitietts 2, Melospiza melodia .5, Vireosylva 
olivacea 2, Vireosylva gilva 1, Dendroica aestiva 2, and Geothlypis trichas 1. 
On the whole the evidence is very plain that these species give to the young cowbirds the 
normal diet for their own nestlings. For instance the Vesper Sparrows were the only birds to 
feed the terrestrial cutworms; but this is a very natxiral thing for these groxind loving birds to 
do. Onl}' Song Sparrows fed carabid beetles, and weevils, and more than a trace of seeds. This 
diet agrees with that described for the sparrows by Judd.l Moreover three of the Cowliirds fed 
by vSong Sparrows had a bunch of vegetable fibers in their stomachs and were the only nestlings 
so favored. The Yellowthroat and Song Sparrow were the only ones to feed snails. The diet of 
the nestlings fed by the Red-eyed Vireo agrees with previous records for this bird in the inclu- 
sion of tree-living homoptera. The youngsters foisted upon Yellow Warblers were the only ones 
treated to moths, an item known to be given to the nestlings of other warblers. 
These records show the adaptability of Cowbirds, a characteristic which must receive a 
severe test in certain cases. For instance the horned larks and various species of blackbirds and 
sparrows, habitually feeil seeds and hard insects to their young. The Rose-breasted Grosbeak 
uses the “nasty” potato beetle for baby food; and the Cedarhird uses a large proportion of fruit. 
Perhaps the greatest departure from the average nestling diet among the species parasitized by 
Cowbirds is in the case of the Turtle Dove. This bird feeds its young entirel}' on vegetable 
matter, some of it half-digested, and mixed with a secretion of the crop, being the substance 
called pigeon’s milk. It would he of great interest to know whether cowbirds are ever reared on 
this palmlum. 
Samuels remarks that “This bird although subsisting principall}' on various seeds aud 
small fruits, destroys great numbers of insects, particularly in the breeding season; in fact its 
young are fed entirely on insects and their larvte, and the well known wire-worms. "2 It has 
justly been observed before that the credit for choice of insects consumed by young Cowbirds 
belongs strictly to the foster parents. Considering the food of adxilt Cowbirds alone the balance 
is in favor of the species. But when we reflect that each Cowbird brought to maturity is the 
cause of the death of three or four birds which would have been just as beneficial in the nest- 
ling stage, and probably more so in later life, the right of the Cowbird' to protection can well be 
questioned. — W. L. IMcATEE. 
Notes on a Broken Leg in the White-rumped Shrike. — My friend. Dr. G. FI. French, 
has called my attention to a peculiarly healed broken leg of a female White-rumped Shrike 
(Lanius ludovicianus excubitorides) , which he 
had collected on February 18, 1911, for mounting. 
The tibio-tarsus and fibula of^the right leg 
had been broken squarely off about three- 
eighths of an inch above the distal end, as is 
shown in figs. I, II and III. The activit}' of 
the bird very evidently had prevented a union 
of the broken ends, which were separated a six- 
teenth of an inch, but which hail finally been 
bridged together by two very strong bone arches. 
As healed, the lower end of the tibio-tarsus had 
a marked lateral bend,but not enough to attract 
attention before dissection. The muscles of 
the lower leg were well developed, which would 
indicate that the shrike had recovered good use 
of its foot. 
Fig. I is a view of the anterior surface, fig. II 
a view of the right lateral surface, and fig. Ill 
a view of the posterior surface. — Clarence Hamilton Kennedy. 
1 Yearbook, U. S. Dept. Agr. [1900] 1901, pp. 419-422. 
2 .Samuels. E. A., U. .S. Agric. Rep. [1864] 1865, p. 426, 
