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THE AMERICAN NATURALIST [Vol. XLIII 



dentally striking the latch when leaping or pawing at the 

 door for admittance. In the present instance there is 

 performed an action which requires the cockerel to leave 

 temporarily the primary object of his attention, and to 

 perform a manoeuvre which it seems could hardly have 

 been hit upon accidentally, while the bird was engaged 

 in the process of feeding. 



Since writing the above paragraphs the writer has 

 made other observations which add new interest to the 

 subject in hand. In order to prevent the buff rock cock- 

 erel from working the feeder a piece of sheet tin was 

 nailed to the beam which had been struck. This was 

 placed over the beam in such a way as to protect the 

 latter on the top, where the cockerel had usually struck it, 

 as well as on the sides. This sheet of tin extended down- 

 ward to within about one-eighth of an inch of the bottom 

 of the beam, and hung about one-fourth of an inch outside 

 of the same. Thus the whole of the beam, except one- 

 eighth of an inch of the lower margin, was protected from 

 the beak of the cockerel, and it was expected that this 

 precaution would effectually prevent all further "work- 

 ing" of the feeder. This result, however, was not forth- 

 coming, for within two days after the sheet of tin had 

 been placed on the feeder the cockerel was found to have 

 modified his behavior to suit the new unfavorable con- 

 ditions. Now, instead of attempting to strike the beam 

 from above, as previously, he reached with his beak un- 

 derneath the projecting sheet of tin, and, grasping the 

 lower margin of the beam, bore it downward with a kind 

 of pulling motion from beneath. This movement, it is 

 apparent, is somewhat different from the one first de- 

 scribed. It is, moreover, the only means by which the 

 feeder could possibly be worked by manipulating any 

 accessible part of beam. It is barely possible to consider 

 the second manoeuvre as a direct modification of the first, 

 although a different part of the beam is struck, and with 

 a different movement on the part of the bird. It is diffi- 



