10 MEMOIRS OF THE NUTTALL ORNITHOLOGICAL CLUB 



and produces a diffuse wliite light more like daylight. The keepers believe that 

 the birds are able to see around them more easily and are not so dazzled as Ijy the 

 old lamps, and therefore none are killed. 



Before taking up in order the various species of birds that are believed to 

 have increased or diminished in the last fifteen years, it may be well to consider 

 the various factors on which this belief is founded, so that we can distinguish 

 between an actual and an apparent increase of birds. It is obvious that an appar- 

 ent increase of any species without an actual increase may be due to a variety of 

 causes which may be summed up as follows : ( i ) protection resulting in a greater 

 lameness of the birds, a nearer view and therefore greater ease of identification; 

 (2) a more general use of powerful prismatic glasses; (3) an increase in the 

 number of observers and an increase in the area covered at all seasons of the year. 



The bird reservations already referred to have made an immediate difference 

 in the tameness or wildness of birds. A gull at King's or Fisherman's Beach will 

 often allow an approach within fifteen yards, whereas on the unreserved beaches 

 it flies off before the intruder has come within a distance of a hundred yards. I 

 have lately seen a flock of two hundred Herring Gulls with three or four Great 

 Black-backed and one Iceland Gull on Fisherman's Beach at Swampscott, and in 

 the water at its edge, separate to allow a man to row off shore. The birds by 

 swimming and a few by flying a short distance barely made way for the oars, and 

 closed the gap as soon as the boat had passed. Under such circumstances one 

 may study at ease any particular bird and compare it with others. 



The second reason is of much interest and should be considered in all its 

 bearings. When I began the study of birds in 1875, I did not use field-glasses 

 but depended on the gun. That was the custom of the few bird-students of that 

 day. In the ornithological books at that time very little was said of field-marks 

 and identification except in the hand. Samuels' " Birds of New England " and 

 Maynard's " Naturalist's Guide " were the chief books of reference owned by 

 students in this region. Cones' " Key " and Wilson's and Audubon's histories 

 were also consulted. At that time and for many years after, — in fact until about 

 the time of the publication of the original Memoir, — it is doubtful if any ornithol- 

 ogist would have been rash enough to report a Glaucous Gull, for example, with- 

 out first securing the specimen. The gun, not the glasses, was depended on and 

 prismatic glasses, which reveal the bird almost as if it were in the hand, were not 

 used to any extent before 1900. With these glasses a bird may be studied at 

 leisure, and every detail of coloring and marking carefully noted even at a con- 

 siderable distance. The use of a powerful telescope as described in the original 

 Memoir is also of great value although it is seldom employed. 



With glasses one can obtain a far better knowledge of habits than with the 



