492 



R. T. YOUNG 



on the perch, shortly after returning to 2 and feeding while on the wing. 

 When I examined the backgrounds all had been taken from 2 and none 

 from 1. 



Experiment 4- The same as preceding except that nine insects 

 were placed on each background. A sparrow, after alighting on the 

 perch, flew over 1 and fed from 2. 



Experiment 5. Figures 28 and 50. The backgrounds and a perch 

 were arranged as shown in the accompanying sketch (fig. H), the perch 

 being about 60 cm. away from the backgrounds, and ten Xyphidium 

 fasciatum were placed on each background, the insect-flour combina- 

 tion showing the greater contrast. A sparrow lit on the perch and then 

 flew to 1 from which it fed. 



Experiment 6. Same as Experiment 5. A sparrow alighted on the 

 perch and then flew to 2 but did not feed, passing instead to 1 from 

 which it took one insect. 



12 3 I 2 



G H 



Figs. G and H A — perch, 1 — flour, 2 — grass. 



Fourteen other similar experiments were performed but in these 

 cases the birds with one exception hopped up to the backgrounds and 

 fed from the one which they first approached, the exception being that 

 of a kingbird which, flying close to the ground, and approaching the 

 background presenting the less contrast first, fed from it on the wing. 



Summary 



The results of this series agree closely with the experiments 

 in the preceding series; in those cases in which the birds ap- 

 proached the backgrounds slowly on foot, the similarity in 

 color between the prey and the backgrounds, had less apparent 

 protective value ;'^'^ while in those cases on the contrary in which 

 the birds approached the backgrounds on the wing, even from 

 a short distance, the resemblance between the prey and the 

 backgrounds showed an evident protective effect. 



«» See pp. 496-7. 



