THE CONDOR 
A Bi-Monthly Magazine of 
Western Ornithology 
Volume XXIV September-October, 1922 Number 5 
[Issued September 22, 1922] 
THE MIMETIC ASPECT OF THE MOCKER’S SONG 
By DONALD R. DICKEY 
WITH FOUR PHOTOGRAPHS BY THE AUTHOR 
BSERVATION of the tender age at which mockingbirds (Mdimus poly- 
glottos) attain a varied and ‘‘imitative’’ song has led the author into a 
train of thought and to a tentative hypothesis that falls admittedly in 
the class of sheer speculation. As such, however, it has interested me, and a 
brief note in that connection is therefore submitted to Conpor readers. Its 
intent is purely suggestive. If it serves no other purpose, it may help to check 
the loose finality with which the mimetic character of this bird’s song is pop- 
ularly ascribed to pure and simple mockery. If the anthropomorphic attitude 
is steadfastly set aside, there remains a serious doubt in my mind as to 
whether this loose, popular acceptation is scientifically tenable. 
On October 14, 1921, A. J. van Rossem collected an immature male West- 
ern Mockingbird which had just completed the post-juvenal moult (no. J 1452, 
collection of Donald R. Dickey). When taken, it was successfully ‘‘imitating’’ 
the notes of the Sparrow Hawk, Kiildeer, and Cactus Wren. The rendition of 
these calls, together with the more characteristic mockingbird interludes, was 
so fluent and skillful as to convince the listener that he was hearing an old 
performer. The very few months which had actually elapsed since this young- 
ster first saw light would seem to form all too short a period for the purely 
imitative acquisition of so varied a repertoire. May not generations of usage 
have made this ability an inherent rather than a mimetic characteristic? 
Disregard for a moment the original manner in which the vocal versatility 
of the species was evolved, for in any event that is lost to us in the unrecorded 
past. Is it folly to suggest that the ‘‘imitative’’ portion of this particular in- 
dividual’s repertoire was as inherent and hereditary in his breast as were the 
true mockingbird phrases? There is a strong suspicion in my mind that if 
this bird had been transplanted as a nestling to a favorable habitat on which 
the note of Sparrow Hawk, or Killdeer, or Cactus Wren, had never fallen, he 
would yet have greeted approaching maturity with ‘‘imitations’’ of their 
songs. In other words, may this not be a ease of parallel ability and adventi- 
tious similarity rather than actual and individual mimicry? 
‘“But,’’ observers will say, ‘‘we have actually heard the cries of unre- 
lated species taken up and repeated by mockingbirds!’’ True, but is this not 
