November 3, 1911] 



SCIENCE 



609 



the freedom ■with which new habits are 

 formed. All procedure is to be directed upon 

 this basis, with variations, if need be, to suit 

 the species or the individual and the state of 

 its instincts at the time. We know, for in- 

 stance, when to successfully approach with 

 the tent the cuckoo or the cedar waxwing, 

 when, the herring gull or the tern, for experi- 

 ment has shown how they may be expected to 

 behave under certain conditions. We have 

 never found " concealing the tent," to which 

 Mr. Beetham devotes a section, necessary, 

 when the element of time was no object, two 

 hours being usually enough to indicate the 

 character of approach permissible. Nor have 

 we ever needed " dummy cameras," nor had 

 to consider " a comfortable position," when 

 using the tent. So far as comfort is con- 

 cerned, we cut the Gordian knot long ago, 

 and should never think of using anything but 

 a commodious tent, in which any one can 

 stand, sit, write or read at ease, and be as 

 comfortable as the temperature will permit. 



If birds are to become accustomed to the 

 tent itself, any question as to its size, form, 

 or even color is of little consequence to them. 

 The occasional nesting of many kinds of 

 birds in incongruous, noisy, or even danger- 

 ous situations surely ought to have made this 

 fact clear. A wall-tent of convenient size, 

 such as we have always used, supported by 

 a compact folding frame, guyed and pinned 

 below, is certainly the best model for general 

 use. 



With many species indeed, an abrupt ap- 

 proach with a plain, unadorned tent is per- 

 missible, whether the original position of the 

 nest be changed or not, while in other cases 

 a more gradual access, with the use of a cer- 

 tain degree of finesse, is as clearly demanded 

 for complete and assured success. In any 

 case our procedure will depend very largely 

 upon the strength of the parental instincts, 

 or the condition of eggs or young. The de- 

 pression of fear and consequent rise of the 

 brooding and other instincts is expressed by 

 fairly definite curves in a given species, and 

 in entire ignorance of such conditions it would 

 be hazardous to pitch any sort of a tent within 



a few feet of any nest, particularly when there 

 were eggs, and fresh ones at that. On the 

 other hand most birds with advanced youjig 

 can be easily approached with the tent, with- 

 out effort to conceal it, whatever the nest's 

 position. In such cases the point is, not to 

 cover the tent with leaves and other " familiar 

 objects," but to make it a familiar object 

 itself, a part of the landscape, as it were; in 

 many cases the birds come to alight on it as 

 they would upon rock or tree. Instinct may 

 excite fear in the unfamiliar, but then habit 

 commonly steps in to allay it, and that often 

 in a surprisingly short time. 



Mr. Beetham's experience with the lapwing 

 is instructive, and one which has been re- 

 peated many times when we have been work- 

 ing with gulls, cedar waxwings and other wild 

 species. In this instance the fear of a timid 

 bird is gradually allayed by habit, until it be- 

 comes indifferent to sounds of whatever vio- 

 lence, and although close to the fixed eye of 

 the camera, it is not readily driven off unless 

 by some decisive movement, as by striking 

 the wall of the tent or waving a hand outside. 

 In all such cases, however, the obvious corol- 

 lary does not seem to have been drawn, 

 namely, use a tent of convenient size, and 

 trust to habit to " conceal " it. 



The author's chapters on work upon cliffs 

 by the aid of ropes, and upon the rapid pho- 

 tography of birds in flight are excellent, but 

 we should have liked more explicit informa- 

 tion on the subject of cinematography, or the 

 making of " moving pictures " of birds, since 

 this is a subject about which very few nat- 

 uralists are informed, in this country at least; 

 ordinarily one might as well consult a graven 

 image for the desired information as any 

 oracle of a trust-controlled business. My own 

 experience in the field has shown that moving 

 pictures to record the activities of life at the 

 nest are readily made, provided the birds have 

 been subjected to the proper training, after 

 methods which we worked out many years 

 ago, when no muffling of the machine, or 

 dummy " musical box," such as the author 

 describes, is commonly necessary: nor should 

 we ever think of covering the protruding legs 



