6 LEAFLELE £20, U. S. DEBE OF AGRICUELURE 
perhaps all posts, with guy wires well anchored in the ground. Fig- 
ure 3 gives suggestions for a pipe framework, fence, and cross Wir- 
ing fora small pond. 
The correct distance between cross wires will depend greatly on the 
kinds of birds it is necessary to exclude. Probably this can best be 
ascertained by experiment in each section. Turning back to ex- 
perience with water-supply reservoirs, it would seem that very wide 
spacing would be satisfactory to keep out large birds in flight. It 
might be well to start with wide spacing and “later on put in addi- 
tional wires as found necessary. The accompanying tabulation shows 
the wing spread of several of the more common fish-eating birds 
that may visit small ponds. It is obvious from reference to the list 
that 2-foot spacing will give a network impenetrable by most if not 
all of these birds in flight. Whether wider interval screens would be 
penetrated will depend on the audacity of the various species. Where 
only the larger forms, with 3 to 6 feet of wing spread, threaten harm 
it is hkely that wires ; spaced at twice those ficures would be a sure 
deterrent. 
Wing spread Wing spread 
Name of bird: in inches Name of bird—Continued. i” inches 
Pied-billed grebe_________ 2224.5 Great blue heron ______-=_ 65-74 
Herning soul ses 2 ees 34-58 Green: heron! 2! =a eee 23-26 
Rie-pilled=cull= =a 4749.5 Black-crowned night 
HorsterS tenn == aes 29-32 heron = Se a ee 4348 
Common tern =. ae 29-32 OSDIrC@Y 23. te a ae 54-72 
American merganser____- 354-39 | Barred owl: 33" 23a 40-50 
Red-breasted merganser__ 31-35 | Great horned owl-__====_ BD-92 
Hooded merganser_______ 24-26.5 | Belted kingfisher_________ 21-23 
Bitte nnin 2 Sor 22: ee 32-30 | 
U.S. GOVERNMENT PRINTING OFFICE: 1936 
~_ 
For sale by the Superintendent of Documents, Washington, D. C. - - - - - - Price 5 cents 
