INTERRUPTED DARK PERIOD: TESTS FOR 

 REFRACTORINESS IN BOBWHITE QUAIL HENS === 



CHARLES M. KIRKPATRICK 



Purdue University Agricultural Experiment Station, Lafayette, Indiana 



The bobwhite quail {Colinus virginianus) lends itself well to labora- 

 tory studies where a wild, native gallinaceous species is required. The 

 species reproduces in confinement, can be held in a minimum of 

 space for indefinite periods, and needs no special feed beyond a 

 balanced poultry ration. Disease is no problem if premises are uncon- 

 taminated, if the birds are kept on wire, and if diseased stock is not 

 introduced. In general, the management of bobwhites for experiments 

 is so similar to the management of chickens that some might question 

 whether confined quail are "wild" or whether they are, in fact, semi- 

 domesticated. However, quail have never been selected, their breed- 

 ing period remains strictly seasonal unless changed experimentally, 

 and such quail when released go wild and do not domesticate. 



Various gallinaceous birds have been induced to lay off-season 

 eggs by extending the day length with artificial lights (pheasants, 

 Martin, 1935; pheasants and quail, Bissonnette and Csech, 1936; 

 ruffed grouse, Clark et al., 1937; chukar partridge. Funk et al, 1941; 

 willow ptarmigan, Host, 1942). If these early experiments suffered 

 for want of fancy equipment or goodly number of experimental birds, 

 they were impressive for winter induction of eggs, sometimes at quite 

 low temperatures. 



More recently (Kirkpatrick and Leopold, 1952) it has been shown 

 that a long night of 14 hr inhibits the reproductive responses in bob- 

 whites, and that interruption of this dark period with 1 hr of light 

 causes quail to produce fertile eggs. When the 1-hr interruption is 

 applied at the m.idpoint of the dark period, the intensity threshold 

 for oviposition is between 1.0 and 10.0 ft-c after treatments for about 



* Journal Paper No. 1202 from Purdue University Agricultural Experiment 

 Station in cooperation with the Indiana Department of Conservation. 



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