160 



Trowbridge — Interlocking of Emarginate 



from the pressure of the adjacent primary but usually a small 

 permanent notch remains, 10 or 15 per cent of the initial 

 width. 



Series 12, 13, 14 and 15 are shown by curves in fig. 13. 



On September 21st, 1905, a specimen of the Marsh hawk, Cir- 

 cus hud sonius, was killed at New Haven, Conn. The bird was 

 shot after it had been coasting for several hundred yards 



12 



































































































































% 























































































• 

















































































































■8. 





















c 































-^ 













> 



































s>s 5 































7 













































































9 







































































































































































7* 











10 







































































































































50 



10D 

 Time in Minutes. 



15[ 



2 OH 



Fig. 12. Series 7 and 8 : Recovery of the web of a first primary feather 

 notched by natural interlocking. Osprey. Pandion haliaetus carol inensis. 

 Series 7 by calipers. Series 8 by photography, see Table VI. 



Series 9 and 10 : Recovery of the webs of the first primaries of the same 

 bird when the feathers were notched by artificial interlocking. Series 7 for 

 1 hour strong pressure, Series 10 for 3 "hours light pressure. 



toward the hill on which the writer was stationed. The left 

 wing was broken near the shoulder; the four (all) emarginate 

 primaries of this wing were interlocked. The right wing pri- 

 maries were partly interlocked, but shot had cut "the feathers, 

 and all the emarginate primaries of both wings had notches in 

 them from four to six millimeters in width. 



