348 THE ANTLERS OF DEER. 
remains all winter in certain portions of Colorado finding 
dant food, should migrate in spring, while a closely allied sp 
or variety, the chestnut-backed snowbird, appears just as’ 
former is leaving, and occupies its place. That an insectiv 
bird, as the wood pewee, for example, should delay its coming 
a month or more after its cousin the phoebe, is explicable by 
supposition that the two birds prefer different varieties of ins 
and migrate only when they are to be found; but in the case 
. the granivorous birds, such an explanation is not admissible. 
same order of coming. The water thrush and the towhee arri 
two weeks earlier in central Iowa, than they do in northern New 
Jersey ; the yellow-crowned warbler and two or three others on the 
other hand, are several days later; while most of the birds ap y: 
about the same time. But however that may be, whether future 
migrations will fully and completely reveal all the causes whigh 
influence the migrations of birds; or whether many of them a 
such as to baffle our researches, the subject loses none of its 
terest because we do not at present fully comprehend it, and 
ever remain one of the most engaging studies in natural history. 
ie 
ON THE STRUCTURE AND CASTING OF THE ANTL 
: OF DE 
BY JOHN DEAN CATON, LL. D. 
_ My investigations of the structure, system of nutriment, 
‘of growth, cause of death and rejection of the antlers of t 
vide have led to results which may interest the readers 
 Narorauist. 
