' MENTAL POWEES OF BIEDS. 
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gallants in spring ; at all events they are the most assiduous in 
their love gambols and songs, as compared with the less bril- 
liantly attired members. This I have repeatedly observed in 
other birds which get additional colourings at the breeding 
season, such as the redpole, American goldfinch, and the deli- 
cately coloured trumpeter bullfinch of Egypt. 
The companion calls of a flock of geese on wing, and the hen 
calling her chicks ; the intercommunication by means of certain 
notes of a flock of finches in a forest, prior to departure, has 
seemingly a linguistic character. The beautiful pine bullfinch 
(Tyrvhula enucleator), found in northern regions of Europe and 
America, retires from the arctic circle in winter to less rigorous 
climates. Flocks of this bird may be seen in the Canadian 
forests in early spring feeding on fir-cones, when the rosy- 
coloured males commence a series of call-notes, which are taken 
up by the sombre-coloured females and young birds of the year 
(the species breeds in very early spring, long before the snow 
has disappeared). These whistlings increase until the trees 
seem alive with Wlfinches ; when suddenly, as if by some pre- 
concerted signal, the entire flock of several hundred birds fly 
off in a body. The quail, when about to migrate, repairs to 
dense covers, often of vetch, where the flock keeps up a sort of 
companion whispering very curious to listen to. This, as in the 
last case, is varied both in tone and intensity all over the field, 
from bitd to bird, when, from these indications or others, they 
depart simultaneously. 
The instinctive desire which comes over the bird at the 
migratory seasons, and compels it to depart, although apparently 
a blind impulse, and not influenced by judgment or reason, is 
assuredly awakened by many causes more or less adverse to the 
well-being of the species. Take, for example, such gregarious 
birds as swallows. The parental duties over, the gradual or 
sudden transition of temperature and consequent failure of 
insect life necessitate a change in the mode of obtaining sub- 
sistence. The insects that were wont to ascend to high 
elevations have now disappeared, and what remain are confined 
to lower levels. Hence the crowding together and ground 
skimming of old and young birds, until the supplies rapidly dis- 
appear and the weather gets colder, when they depart in a body 
before the north winds or in the face of the balmy southern 
breezes which indicate the route to Africa. It has been often 
observed that many migratory birds have been driven, through 
the instinctive impulse, to abandon their second broods and 
leave them to perish miserably. This is the case with swallows; 
and I noticed during two seasons in Canada the same in con- 
nection with the Carolina Waxwing, which arrives in the 
eastern provinces in June and departs abruptly in August ; but 
