306 BULLETIN 196, UNITED STATES NATIONAL MUSEUM 



be associated with vehement singing, the head is stretched almost 

 straight upward or even actually inclined backward, displaying the 

 blue gorget and red or white spot to the full, while the tail is strongly 

 cocked or jerked up and down and the wings drooped. This posture 

 seems to have been first described by Ziemer (1887), who observed it 

 in the male of a captive pair of the white-spotted form in an aviary. 

 He writes (translation) : 



While the female now sat quiet and apparently indifferent in the middle of the 

 cage on a little eminence, the male for some time ran about restlessly and evidently 

 excited, jerking his tail and calling from time to time. Then he began to sing, at 

 first softly and intermittently, then gradually louder and more continuously, 

 until finally he drooped the wing tips even more than usual, so that they almost 

 trailed on the ground; then he fanned out his tail and cocked it up to beyond the 

 vertical, laid the head so far back that it almost touched the tail, and then, singing 

 with all his might, pirouetted round the female in this attitude, thus showing off 

 his finery to the full and from time to time making bowing movements. Bustling 

 about in this way he moved only his feet, while he remained in the same stiff 

 posture, so that it looked as if he were being driven by clockwork. 



It is necessary to exercise some caution in basing accounts of bird 

 behavior on observations under the necessarily somewhat unnatural 

 conditions of captivity, but in tins case we have sufficient supporting 

 evidence from field observation to justify the conclusion that the 

 behavior described was essentially normal, and Ziemer's account is 

 valuable because it enables us to fill in some details of a display that 

 is difficult to observe adequately in nature because it is generally 

 performed in cover and often, it appears, toward dusk. Otto Natorp 

 (1928) records observing a pair of white-spotted bluethroats in the 

 dusk, the male moving round the female with the head stretched up- 

 ward and backward and the tail strongly cocked, just as Ziemer de- 

 scribes, and he states that he observed a similar display on another 

 occasion. Again, Aplin (1903) describes a male of the red-spotted 

 form singing ecstatically with head and neck stretched up, bill pointed 

 nearly upward, tail flirted up and down or held at rather less than a 

 right angle with the body and wings drooped, while the female was 

 creeping and hopping about in the Arctic birch scrub close by. In all 

 these cases the display as described seems to be fairly definitely a 

 courtship performance, but it should be observed that in the related 

 European robin a closely similar posture, displaying the red, instead 

 of blue, breast, has been shown to be an aggressive or threat posture 

 and not sexual at all. This naturally raises the question whether the 

 same may not be really true of the bluethroat, but the recorded 

 accounts do not favor this supposition and more observation is desir- 

 able. It would not be unprecedented for fundamentally the same 

 posture to be used in different situations in two species. 



Finally it must be mentioned that although the male sings freely 



