UNITED STATES DEPARTMENT OF AGRICULTURE 



MISCELLANEOUS CIRCULAR NO. 69 



Washington, D. C. 



Issued June, 1926 

 Revised November, 1926 



CONSTRUCTION AND OPERATION OF BIOLOGICAL 

 SURVEY BEAVER TRAP 



VERNON BAILEY, Biologist, Division of Biological Investigations 

 Bureau of Biological Survey 



THE BEAVEE TEAP devised by the Biological Survey and 

 described in Department Bulletin No. 1078, "Beaver Habits, 

 Beaver Control, and Possibilities in Beaver Farming," has been 

 greatly improved and strengthened until entirely satisfactory in 

 operation. The new trap (fig. 1) has been thoroughly tested, and in 

 March, 1926, a patent was obtained for the writer by the Department 

 of Agriculture and dedicated to the use of the people of the United 

 States. It is designed chiefly for capturing beavers alive for control 

 and propagation, and can be manufactured by anyone for personal 



use or for sale. The 

 specifications and direc- 

 tions that follow should 

 enable any machinist or 

 practical mechanic to 

 make the trap, at a cost 

 for materials, in small 

 lots, of about $7, and for 

 shop work about $3. 



B2937M: BI93SM 



Fig. 1. — Biological Survey cage 

 trap for taking beavers alive. 

 A, Trap held partly open to 

 show construction. B, Trap set 



and ready to be placed in the water. The trigger stands erect in the center of the 

 set trap 10 to 12 inches high, so that when struck on any side by a swimming 

 beaver it releases trigger bars and springs, and then the trap jaws close and lock 

 above the captive animal. Details of construction shown in Figure 2 



MATERIALS REQUIRED 



(Italic figures in parentheses show the part as illustrated in Figure 2) 



1 cold-rolled steel bar 1*4 by % by 52 inches, for base bar (1). 



2 cold-rolled steel bars each % by & by 83 inches, for trap jaws (5). 

 1 piece of flat iron 1% by % by 52 inches, for cross bar (2). 



1 piece of flat iron 1 by *4 by 13 inches, for top cross bar (3). 



2 pieces of flat iron each 1 by % by 11 inches, for short cross bars U). 



2 pieces of strap brass each % by t^ by 6 inches, for clasping hooks (fj). 



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