sw1 r'rs. 239 
     
    
   
   
    
     before the ground is reached he ('llet-ks his rapid descent by an abrupt 
     
     turn, and on leisurely wint,r again mounts upward to repeat this game 
     
     of slx’y—coastiiw. At, the moment the turn is made one may hear a. 
     
     rushing, booming sound. which, as writers have remarked. can be imi— 
     
     tated in tone by blowing,r across the bung-hole of any empty barrel. It 
     
     is made by the passage of the air through the bird‘s primaries. 
     
    

    
     In late summer Nighthawks gather in large [locks and begin their 
     
     southward migrations. When flyingr the white mark on their primaries 
     
     is a conspicuous character, and has the appearance of being a hole in 
     
     the bird‘s win". 
     
    
   
   
    
     4201). C. V. chapmani (Fours). FLUIHDA NIHIITIIAWK: Bt'urnu‘. 
     
     —Similar to the, preceding. but smaller. and with the white and ereanisbutf 
     
     markings ot'the upper parts more numerous. l... sato; \\'.. 7-10: T.. 4'10. 
     
    

    
     It’d/(yaw—l‘lt‘eeds in Florida and \\'estward on the Gulf coast; south in win- 
     
     ter to South America. 
     
    
   
   
    
     The W |-' " ZRN Nion'rnuyi; 4301/. I', w, I). ”717/ r, a near relative of our spe— 
     
     eies, has been recorded from \Vaukegan. lll. 
     
    
   
   
    
       
     
    
   
   
    
     FAMILY MICROPODIDE. SWIFTS. 
     
    
   
   
    
     The seventy-five known species of Swifts are distributed through- 
     
     out the greater part of the world. About one half this number are 
     
     American. but only four are found in North America. Swifts are 
     
     generally found associated in scattered companies. and when roosting 
     
     or nesting are eminently gregarious. Ilollow trees and caves are their 
     
     natural retreats, but in some parts of the world chimneys are now used 
     
     exclusively. 
     
    

    
     They feed entirely while flying. and with their unusually long 
     
     wings and small. compactly feathered bodies possess unrivaled powers 
     
     of flight. Swifts are popularly confused with Swallows. but. the re— 
     
     semblance is only superficial and exists chiefly in the similarity of 
     
     their feeding habits. while the structural ditfereuees between the two 
     
     are numerous and important. 
     
    
   
   
    
     423. Chaetura. pelagica, (Lin/1.3. (‘nmx ‘y SWIFT; (‘nmxmi 
     
     “S\\'.\t.t.o\\‘." (See Fig". WM .trl.~l‘lntire plumage t'nseons. more grayish on 
     
     the throat; a sooty black spot before the eye' shafts of the tailrt'lathers ex— 
     
     tending beyond the \‘anes. l... 5'43: \\'.. 4'14: 'l'.. l‘Wt: Ii. t'rom .\'.. ‘13. 
     
    

    
     [fully/v. ,, liastern .\'orth America: breeds from Florida to Labrador: Win- 
     
     ters in ('t-ntral .»\nn-riea. 
     
    

    
     Washington. abundant S. It. .\pl. 15 to Ot-t. to. Sing Sing. common 
     
     S. R. .-\pl. 1‘.) to (let. 2:5. t'anibridue. abundant H. lx’.. .\pl. 2.7 to Sept. ‘10. 
     
    

    
     A\;.\'f.1l bracketlilu- basket of dead twigs glued together with saliva; ut- 
     
     taehed to the wall of a chimney. generally about ten feet from the top, by