Fig. 116. Imitation Egret without plumes 

 photographed against white (substituted for 

 sky), to show that the shadows which 

 reveal the form come at the very points 

 normally covered, at the breeding-season, 

 by the so-called "nuptial" plumes. These 

 points are indicated by the arrows. The 

 knife-like thinness of the throat, where' 

 plumes would incommode him, largely 

 obviates the need of them at this point, 

 by minimizing the shadow. 



Fig. 117. Imitation Kgretin nuptial dress,, 

 photographed against black, to show the' 

 position of the plumes. 



Fig. 118 a. A is a section of the Egret, B 

 the roof-like plumes. C the dark under side- 

 which they hide. The part of a heron's 

 neck that normally bends backward as he- 

 stands has the roof's ridge-pole in front, and 

 the eaves behind. 



Fig. 118. Imitation Egret in nuptial plu- 

 mage, photographed against white, showing 

 the effect of the plumes in effacing the shad- 

 ows, thus rendering the bird almost invisible- 

 when seen against the sky. This is achieved 

 on the model, as on a real Egret, in the only 

 conceivable way : the plumes extend down- 

 ward and outward, like a roof between the 

 beholder's eye and the shadow to be covered. 

 Because of this roof-like position, they stay 

 illuminated throughout their whole length, 

 and interpose their bright fringe between 

 the beholder and the shadowed undersides 

 of the neck and body. The fact that these 

 fringes cross the bird's contour, and follow 

 that of the vegetation in which he stands, 

 greatly helps the concealment. White fluffs 

 or fringes of this general character, screening, 

 the too deeply shadowed abdominal space, 

 between the legs, are very common among? 

 birds and mammals. 



