AIDS TO NESTING 219 



Farmer's Bulletin No. 609, quoted above, as admitting 

 sufficient light while the martin enters. In view of the 

 spread of the starling, which is Hkely to make trouble for 

 the martins, a good suggestion is made by Raymond B. 

 Thompson in Guide to Nature, January, 1915. It is that 

 the diameter of the entrance-hole be made if inches, which 

 is a close fit for the martin, but will just exclude the starhng, 

 as elsewhere described in this chapter. To allow for the 

 admission of light, another hole, about J inch in diameter, 

 is cut just above the entrance-hole. This looks like a clever 

 scheme, and let us hope that the martins may not object 

 to a tight fit! The experiment is well worth trying. 



Location and Care. The house must be set on a pole out 

 in the open, away from trees, and should be 15 to 20 feet 

 from the ground. A very convenient plan often adopted 

 is to have the pole so that it can be lowered. It is set up 

 between two short posts or bitts, with two long bolts reach- 

 ing through all. When desired, the lower bolt can be taken 

 out, and the pole swung over on the upper one as a pivot, 

 thus bringing the house to the ground. It should be cleaned 

 out every fall and all nests and rubbish removed. If left 

 up, it is wise to stop up the entrances to keep out Enghsh 

 sparrows, which would dirty it during winter and build 

 nests before the martins returned. A better plan is to take 

 it down and house it for the winter, putting it up again when 

 the martins are due, which in the latitude of New York 

 City would be about the middle of April. 



Starting a Colony. Colonies once started usually con- 

 tinue year after year. The tendency is for the colony to 

 grow larger and larger, doubtless from the return of the 

 young. There is not much hope of enticing old birds from 

 their chosen location, but the young birds are often crowded 

 out, and may start a new colony if they find a site to their 



