Physiology. — ‘Factors which are of vmportance for the habit- 
formation of birds. I. Visual sensations” *). By Miss Lucin W. 
Scuut. (Communicated by Prof. G. van RIJNBERK.) 
(Communicated at the meeting of June 26, 1920). 
Introduction. - 
In 1918) Buisrenpijk described experiments on habit-formation 
in birds. He found that a siskin very soon learns to look for food 
in a seed-box, where the food is hidden from sight by a flap. When 
this box is placed amongst similar, but empty ones, the bird invariably 
will go to the filled box, provided it is always kept in the same place 
amongst the others. The habit formed in this way was not forgotten, 
even after the bird having been taken for months to other surround- 
ings, for on itsreturn. placed in front of the same boxes, the bird at 
once flew to its old box for food. 
Control and corroboration of ButsTENDIIK’s results. 
I repeated the experiments made by Buistenpijk and arrived at 
the same results as he did. The birds I selected for the experiments 
were the siskin (Fringilla spinus, 3 specimens), the redcap (Fringilla 
carduelis, 2 specimens), the paradise widow (Steganura paradisea, 2 
specimens) and the Napoleon weaver (Pyromelana afra, 2 specimens). 
It is surprising how rapidly all these birds, but above all the siskin, 
learned to push their heads under the flap of the food-box. The siskins 
accomplished the task at the first trial, within fifteen minutes. The 
others took a little longer, the experiment having to be repeated 
regularly for a few days in succession. If, further, I replenished one 
particular box, placed amongst four similar ones, from the very 
beginning, as the rule was, the birds were equally quick in learning 
to look for food in that special box and rarely tipped up the flaps 
of the other boxes. Buirenpijk believes that the fixed place the 
feeding-box takes amongst the others, is the ruling element in this case. 
1) Afler experiments made in the physiological Laboratory of the University of 
Amsterdam. 
2) F.J. J. BuwrenDijK. Proeven over gewoontevorming hij dieren. Amsterdam 
1918. 
