554 MIGRATION 
throughout the year. It has long been known that Birds-of-Prey 
customarily drive away their offspring from their own haunts so 
soon as the young are able to shift for themselves. The reason 
generally, and no doubt truly, given for this behaviour, which at 
first sight appears so unnatural, is the impossibility of both parents 
and progeny getting a livelihood in the same vicinity. The 
practice, however, is not limited to the Birds-of-Prey alone, but is 
much more universal. We find it to obtain with the Redbreast, 
and if we watch our feathered neighbours closely we shall perceive 
that most of them indulge in it. The period of expulsion, it is 
true, is in some Birds deferred from the end of summer or the 
autumn, in which it is usually performed, until the following 
spring, when indeed from the maturity of the young it must be 
regarded as much in the light of a voluntary secession on their 
part as in that of an act of parental compulsion, but the effect is 
ultimately the same. These cases, however, which make certainly 
the exception rather than the rule, we can account for in another 
manner. It is to be observed that they are confined to species 
having a peculiar mode of life, the individuals associating in family- 
parties to form small bands. The members of the TITMOUSE- 
Family (Paridzx) offer a good instance of this peculiarity, but it 
requires no very abstruse reflection to perceive that the adoption 
of this habit is one eminently conducive to the easy attainment of 
their food, which is collected, as it were, into particular spots often 
far apart, but where it does occur occurring plentifully. Thus a 
single Titmouse searching alone might hunt for a whole day with- 
out meeting with a sufficiency, while if a dozen are united by the 
same motive it is hardly possible for the place in which the food is 
lodged to escape their detection, and when discovered a few call- 
notes from the lucky finder are enough to assemble the whole 
company to share the feast. It is impossible to watch a band of 
any species of Titmouse, even for a few minutes, without arriving 
at this conclusion. One tree after another is visited by the active 
little rovers, and its branches examined: if nothing be forthcoming 
away goes the explorer to the next that presents itself, merely 
giving utterance to the usual twitter that serves to keep the body 
together. But if the object of search be found, another kind of 
chirp is emitted, and the next moment the several members of the 
band are flitting in succession to the tree and eagerly engaged with 
the spoil.” 
1 Tt is a very ancient remark about young Ravens that ‘‘ they wander for lack 
of meat.” 
2 The case is altogether different with those species which in winter form 
themselves into large flocks, as most of the Finches (/ringillidz) and Buntings 
(Emberizidz). The discoverer of.a favourite morsel perhaps by his actions 
betrays what he has obtained, and accordingly his fellows mav repair to the 
