82 BULLETIN 196, UNITED STATES NATIONAL MUSEUM 



or two and though apparently fierce no damage seemed to result. It was particu- 

 larly noted that in the chasings the birds always ran with very rapid steps, they 

 never hopped : that their beaks remained closed and that they uttered no sounds. 

 Those birds which for the moment were not actively engaged in these performances 

 stood motionless with wings and tail spread and depressed and with feathers 

 fluffed out as above described, but the head, neck and beak stretched upwards 

 and forwards at an angle of about 45 degrees giving them a curiously melevolent 

 expression. This first-seen display was so spectacular that it excited the curiosity 

 of two other people who took little or no interest in bird behavior. 



The display was seen on February 10, beginning at about 7.15 

 a. m. and lasting till about 7.55, with one interruption of some 10 

 minutes. Regvlar watching was then instituted in the early morning, 

 and the displays continued until April but were very irregular. 

 Really active displays only took place on a few days. "On a few oc- 

 casions two or more females appeared on the scene and might chase 

 each other or be chased by single male birds." Some similar evening 

 displays were also observed. 



Variations of the formalized drill-like movements which Lack men- 

 tions have since been recorded by others. A. W. Boyd (1941) has 

 described three males moving about in a triangular formation, maintain- 

 ing their relative positions as the triangle turned first one way and then 

 another, and J. Staton (1941) observed four moving about in single 

 file 2 or 3 feet apart in the posture which Lack's birds assumed when 

 not actively performing, with beak elevated at about 45°. It will 

 be apparent that these displays are of no fixed form and that different 

 groups may "improvise," as it were, their own particular version, but 

 the common sort of performance seems to be that consisting of little 

 but indiscriminate, often mechanical-looking, chasings without con- 

 spicuous posturing. The displays recorded by Miss Morley were of 

 this type. 



It will probably not have escaped the reader that some of the pos- 

 tures mentioned, such as the depressed and fanned tail and the head 

 stretched upward, are much like those described under courtship, but 

 the former at any rate is a generalized excitement posture, and hi any 

 case it is no unusual occurrence in bird life for the same posture to be 

 used in more than one type of situation. It seems clear that these 

 communal tourneys are not in any direct sense sexual, though they 

 may be in some vague way related to the reawakening of sexual im- 

 pulses and the associated (primarily territorial) aggressiveness. 

 But in fact their significance remains problematical. 



In fall and winter blackbirds also display a communal tendency 

 in their roosting habits, and may gather in considerable numbers to 

 roost in shrubberies, plantations, thickets, and old overgrown hedge- 

 rows, often in company with redwing thrushes and fieldfares. Excite- 

 ment rises as roosting time approaches and the birds become very 



