THE PROTECTION OF BIRDS. 409 



ful Birds," in which he gives a method of protecting their 

 nests from their enemies. Of sixty-seven nests observed 

 from April to August, only twenty-six prospered. Of the 

 forty-one destroyed, fifteen were known to have been robbed 

 by cats, eight by the garden dormouse, three by Jays, and 

 two by Magpies. He protected twenty nests either by fur- 

 nishing the birds vermin-proof bird boxes to build in, or 

 by surrounding the nests with wire netting. Only two of 

 these were robbed of eggs or young, and thej^ were pillaged 

 by animals that got through or under the netting. These 

 simple methods of protection assured the rearing of one hun- 

 dred and two young birds from nineteen nests. Comparing 

 these figures with those from the unprotected nests, w^e find 

 that, proportionately, only seven pairs of parents out of the 

 twenty would have succeeded in rearing their young had 

 their homes been unprotected. The paper lacks a complete 

 description of the method of putting up the wire nest pro- 

 tectors. There is nothing to show wdiether the enclosure was 

 without a cover, or whether an opening Avas left in the top 

 just large enough to admit the parent birds ; but the mesh 

 used was, in some cases at least, small enough to keep out 

 mice, or about one-fifth to one-sixth of an inch in diameter. 

 The language used seems to indicate that the nests on the 

 ground were merely enclosed by a circular fence of wire 

 netting. Mons. Raspail says that nests so protected are not 

 attacked by weasels or mice. There seems to be nothing 

 to prevent these animals from climbing over the wire, except 

 that they may stupidly strive to get at the nest from below, 

 and so walk around the cage without seeking an entrance 

 above. The sly fox, perceiving the smell of iron, might sus- 

 pect a trap. Probably Crows and Jays, being also suspicious 

 of a trap, would not enter these enclosures. The surround- 

 inof of the nests with nettino; in no case caused the birds to 

 desert their home, even when it was done as soon as the nest 

 was completed and before the eggs w-ere laid. This method 

 might be worth a trial. 



Where nesting trees are isolated, cats and squirrels may 

 be kept out of them b}^ the use of either of the devices shown 

 in the cut (Fig. 171 ) , for these animals cannot climb up a per- 



