117 



regular migrations, and have consequently no accustomed winter 

 quarters, are most erratic both in choice of the latter and of their 

 breeding grounds. The wanderings of the Bohemian Waxwing, 

 Rose-coloured Pastor, and the Common Crossbill may be pointed 

 out as well-known instances of these erratic habits. Why, there- 

 fore, should not the latter species be equally endowed with this 

 sense of locality and direction, unless it is because this faculty 

 has been acquired through slowly inherited experience. 



Herr Gatke, however, objects to theories of this kind on the 

 grounds that the term unconscious inherited experience is nothing 

 but another name for instinct. He remarks: " Can experience be 

 something of which the subject is altogether unconscious ; and 

 further, can experience, the result of which is positive knowledge, 

 be actually inherited ? " To the writer he has here fallen into the 

 error of confusing inherited experience with experience gained 

 during life. Unconscious inherited experience is the sum total 

 of the latter acquired during the lives of many previous genera- 

 tions the experience of the race not of the individual. We see 

 all around us every development of the nest building instinct 

 from the lovely structure of the Long-tailed Tit to the simple 

 depression in the sand of the Oyster-catcher. The former species 

 by inherited experience unconscious why it does so selects 

 materials in building its nest which will harmonise with the 

 lichen-covered branches of trees, thus rendering the nest incon- 

 spicuous. Were it conscious of the reason for selecting such 

 material, however, it would hardly make the frequent blunder of 

 placing the nest, early in the spring, in some hedge-row, where 

 these very materials have exactly the opposite effect, the foliage 

 not being sufficiently advanced to afford the necessary conceal- 

 ment. There can be no doubt that the natural site for the nest 

 of this species, and indeed, which is most often selected, is the 

 fork of some lichen -covered tree. 



That the instinct or hereditary impulse varies in strength, not 

 only in species but also in local clans of the same species, there 

 is abundant evidence to show. Many birds which are strictly 

 migratory in the north of Europe are sedentary in our own 

 country, and moreover, the latter on the advent of exceptionally 

 severe winters of long duration, perish in large numbers, appa- 



