24 



It will be seen from this table that the average number of eggs 

 found in each moth is 185, Mr. Bailey is very positive, from his 

 continuous field observations, that each chickadee will devour on 

 the average 30 female canker-worm moths per day from the 20th 

 of March until the 15th of April, provided these insects are plen- 

 tiful. If the average number of eggs laid by each female is 185, 

 one chickadee would. thus destroy in one day 5,550 eggs ; and in 

 the twenty-five days in which the canker-worm moths "run" or 

 crawl up the trees, 138,750. It may be thought that this compu- 

 tation is excessive, and it is probable that some of the moths were 

 not captured until they had laid some of their eggs, but the 

 chickadees are also busy eating these eggs. When we consider 

 further that 41 of these insects, distended as they were with eggs, 

 were found at one time in the stomach of one chickadee, and that 

 the digestion of the bird is so rapid that its stomach was probably 

 filled several times daily, the estimate made by Mr. Bailey seems 

 a very conservative one. He now regards the chickadee as the 

 best friend the farmer has, for the reason that it is with him all 

 the year, and there is no bird that can compare with it in destroy- 

 ing the female moths and their eggs. It was noticed that the birds 

 made no attempt to catch the male moths. This, however, cannot 

 be considered as a fault, for the birds accomplish far more by 

 destroying the females than they would by killing males. 



The following notes from the preliminary examinations of the 

 contents of the alimentary canal of chickadees made by Mr. Kirk- 

 land are of interest in this connection : — 



" Bird brought in by Mr. Bailey, March 16, 1895 : Gullet empty. 

 Gizzard contained 270 canker-worm eggs {Anisopteryx pometaria) , 

 46 case-bearers (microlepidoptera) , 6 cocoons of a small tineid 

 (near Asjyidisca). These three kinds of food in bulk composed 

 80 per cent of the gizzard contents, the remainder being dark 

 material which I was unable to determine under a hand lens. I 

 think it very probable that part of this was bits of bark or parti- 

 cles of bark-dust taken in with the eggs or cocoons. The intes- 

 tine contained a large quantity of meat, 75 per cent, and 103 

 canker-worm eggs, 10 per cent, the remainder, 15 per cent, 

 being material which I could not identify. It was not meat. This 

 gives us as totals, 373 canker-worm eggs and 52 microlepidoptera. 



" Specimen of so-called ' scales ' on apple twigs brought in by Mr. 

 Bailey, March 12, 1895. These are not bark lice, but the cocoons 

 of a microlepidopteron, probably a tineid. Length, jV ^^ h i'^ch ; 

 width, yig" to \r ^^^^^ ' elliptical, dark brown or reddish brown. 

 They are closely spun, the upper surface apparently being of leaf 

 epidermis, while underneath is a small, well-formed cocoon which 



