Development and Care of the Young 191 



head depressed, the Robin is usually engaged in errands of this 

 kind. The Robins and Cedar-birds have frequently been seen to 

 take the sacs from two or three birds in rapid succession, in which 

 case they are always devoured on the spot. The Robin will 

 often convey the package to 

 any convenient perch, and, 

 after examining it, devour a 

 part, or reject the whole. While 

 watching Robins from the tent, 

 I have seen them carry the ex- 

 creta thirty rods away before 

 letting it fall or alighting to ex- 

 amine it, and have tried to find 

 the sac but usually without 

 success. One day I saw a 

 male Robin drop the "white 

 marble " in the grass about fifty 

 feet from the nest, and proceed 

 to peck at it. Upon going to 

 the spot a little later I found 

 the sac covered with dirt but 



not opened. It had a tenacious opaque white wall, was per- 

 fectly odorless, and contained, besides a few small pellets, a 

 whole blueberry which had survived the digestive process. The 

 actions of the old bird were thus explained. He was looking 

 for food on his own account, but in this case missed it. 



Not only are the young carefully tended in the way ex- 

 plained, but the old birds often put the head down in the nest 

 and rummage about for any stray particle of food or fragments 

 of any kind which it is desirable to remove. While standing at 

 the nest they will sometimes pick energetically their own legs 

 and toes, and the heads and bodies of the young, a very im- 

 portant function where the nest is infested with those minute 

 swarming particles known as lice and mites. Every straw and 

 fiber in the Cedar-bird's nest shown in one of the photographs 

 (Fig. 50) was literally covered with parasites, in this case a 

 species of mite which is a poor and degenerate relation of the 



Fig. 119. Flicker cleaning the nest. 



