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BIRDS OF THE REPUBLIC OF PANAMA — PART 2 



During March and April I have noted them sailing rapidly, two 

 together, with wings held stiffly elevated to form a V over the back, 

 part of a mating display as some of those taken at this time had the 

 gonads definitely enlarged. Occasionally their activities over old fields 

 were such that I believed that they were nesting in hollow trees. The 

 salivary glands were prominent in a male taken June 3, near Sona. 



Figure 37. — Vaux's swift, vencejo oscuro comun, Chaetura vauxi. 



Like related species, Vaux's swifts come regularly to ponds, and 

 open stretches of quiet water on the larger streams, to drink and 

 bathe. In the latter operation they may strike the surface rather 

 heavily. On such occasions, as they rise and shake the feathers, drops 

 of water may fall like rain. 



Two geographic races are found in Panama. 



