58 'Journal of Comparative Neurology and Psychology. 



ally until the twenty -fourth day). Another young one, in contrast, 

 was only learning to eat on the twenty-third day, begging very hard 

 from its parents, who were by this time unwilling to feed it, and it 

 w^as still fed in a spurious fashion by the father on the thirtieth day. 

 ISTow^, as to the sound w^hich forms an important part of the begging 

 expression. About the time the young bird first leaves the nest tlie 

 voice makes a sudden growth ; the little peep which has been made in 

 begging for food grows much stronger and becomes somewhat squeaky 

 in tone. It continues to grow louder almost as long as the begging 

 note is used, that is, almost until the parents quit feeding. It is at 

 that time a sibilant squeak beginning soft and low, becoming rapidly 

 higher and louder, and then ending abruptly. It may be imitated 

 by whistling the letter S through the teeth, loudly, with the inflection 

 just described. This (K'o. 25 of the musical notations) is the em- 

 phatic note, given when the bird is begging hard from the parent. 

 But when its enthusiasm dies down, its note becomes lower, softer, 



and shorter, until it may, become a gentle "st" like ^o. 28. The 

 pitch, as can be seen, varies through a great range. While it ranges 

 very much low^er than that of the young nestling, I think it may also 

 extend as high as the highest notes of the nestling. 



A slight shaking of the wings when begging for food is noticed, 

 as was mentioned above, before the young have left the nest. This 

 shaking of the wings becomes more ample as the voice becomes 

 stronger, until, in a pair of three-week-old birds, it makes a lively 

 scene. Each young one stands in front of its father (or mother), 

 sticking its bill into his face and trying to push it into his mouth, 

 squeaking without intermission, wath its wungs htilf spread and 

 flapping strongly, following the father wherever he goes, and running 

 around him if he attempts to turn away, every movement being made 

 to an exaggerated degree. If parent and young happen to stand 

 side by side, as they are compelled to do when on a perch, for example. 



