The Singing of Birds. B.P.Bicknell. 



Turdus ustulatus swainsoni. Olive-backed Thrush. 



This Thrush is in full song during its spring migration, which 

 occupies the latter fialf or two-thirds of May, hut is commonly 

 silent in the autumn. It is, however, probable that singing may 

 occasionally be indulged in that season, for I was assured by one 

 who was familiar with the song of the species, that several were 

 heard singing at Bay Ridge, Long Island, September 26, 1S80, at 

 the height of their migration. 



On their arrival in September the new plumage has not always 

 completed its growth. In many specimens growing feathers are 

 scattered over the body, and often some of the remiges have their 

 bases still soft, or even sheathed by the matrix of the feather. 

 When the birds first appear they have begun to develop adipose 

 tissue, and it is not long before they become excessively fat. 



Auk, I, April, 1884. p. /J19-/JO » 



I 



^ -of 1891 some very interestir/g observations were 



Tiade as to thfeir song habits. The song of the Olive-backed Thrush 

 begins low and ascends by two regular steps of two notes each, and enils 

 with several sharp notes. The first note of each step is higher than the 

 second, and the second of the next is about the same as the first note of 

 tlie first step. Occasionally the whole is preceded by a sharp chuck. The 

 notes have the swelling beauty of all Thrush songs, while the metallic 

 ending rings like a little bell. The song always says to me, — gnrgle 

 gurgle ting., die che che. As far as my experience goes, this Thrush never 

 sings steadily except in his chosen tree; in fact for two years one Iins 

 selected for his perch a small evergreen near our cottage, and it was from 

 him that I procured the following data. 



He sings on an average nine and a half times a minute with extreme 

 regularity. During the song periods of morning and evening his con- 

 stancy of purpose is remarkable; except to seize a passing insect, lie never S 

 breaks the regular recurrence of his song. From a series of records it is g 

 found that he begins on an average about 3.15 A. M., and sings steadily (of ^ 

 course I mean by that ten times a minute, not constantly) until about '"w^ 

 9.00 A. M. ; he is nearly silent until noon, after which he sings occasionally ' § 



tor a minute or so. About 4.30 he begins again, and only ceases to retire O 

 for the night about 7.30 p. m. This is a wonderful record, and were it not 

 verified by long experience, I should myself be inclined to consider it 

 exceptional. Allowing but eight times a minute for his songs, we have, 

 for one day, the time consumed in song periods about eight hours and 

 forty-five minutes, and in occasional song, at least twenty minutes, 

 according to which there would be a total of 4,360 songs per day. His 

 song ceased entirely about July 25, although for five days before that but 

 half the time was employed. Certainly it would not be unfair to allow 

 him at the very least six weeks of song, 42 days at 4000 per day, in all 

 j68,ooo songs in a season. The above facts have been many times verified. 



