370 MENTAL EVOLUTION IN ANIMALS. 



tubular entrance, or with a mere ledge. The date of a similar change in the 

 habits of Il.fitlra is also known. 



In all changes, whether from persecution or convenience, intelligence 

 must come into play in some degree. The Kitty-wren (T. vulgaris), which 

 builds in various situations, usually mates its nest to match with surrounding 

 objects (Macgillivray, vol. iii, p 21) ; but this perhaps is instinct. Yet 

 when we hear from White (Letter ] 1) that a Willow-wren (and I have known 

 a similar case), having been disturbed by being watched, concealed the orifice 

 of her nest, we might argue that the case was one of intelligence. Neither 

 the Kitty-wren nor Water-ouzel (" Mag. of Zool.," vol. ii, 1838, p. 429) 

 invariably build domes to their nests, when placed in sheltered situations. 

 Jesse describes a Jackdaw which built its nest on an inclined surface in a 

 turret, and reared up a perpendicular stack of sticks ten feet in height — a 

 labour of seventeen days : families of this bird, I may add (White's " Sel- 

 borne," Letter 21), have been known regularly to build in rabbit-burrows. 

 Numerous analogous facts could be given. The Water-hen (G-. cliloropus) is 

 said occasionally to cover her eggs when she leaves her nest, but in one pro- 

 tected place W. Thompson (" Nat. Hist. Ireland," vol. ii, p. 328) says that 

 this was never done. Water-hens and Swans, which build in or near the 

 water, will instinctively raise their nest as soon as they perceive the water 

 begin to rise (Couch "'illustrations of Instinct," p. 223-6). But the follow- 

 ing seems a more curious case : — Mr. Yarrcll showed me a sketch of the nest 

 of a Black Australian Swan, which had been built directly under the drip of 

 the eaves of a building ; and, to avoid this, male and female conjointly added 

 semicircular * to the nest, until it extended close to the wall, 



within the line of drip ; and then they pushed the eggs into the newly added 

 portion, so as to be quite dry. The Magpie (Corvus pica) under ordinary 

 circumstances builds a remarkable, but very uniform nest ; in Norway they 

 build in churches, or spouts under the eaves of houses, as well as in trees. 

 In a treeless part of Scotland, a pair built for several years in a gooseberry 

 bush, which they barricaded all round in an extraordinary manner with 

 briars and thorns, so that " it woidd have cost a fox some days' labour to 

 have got in." On the other hand, in a part of Ireland, where a reward had 

 been offered for each egg and the magpies had been much persecuted, a pair 

 built at the bottom of a low thick hedge, "without any large collection of 

 materials likely to attract notice." In Cornwall, Mr. Couch says he has 

 seen near each other, two nests, one in a hedge not a yard from the ground 

 and " unusually fenced in with a thick structure of thorns ;" the other " on 

 the top of a very slender and solitary elm — the expectation clearly being 

 that no creature would venture to climb so fragile a column." I have been 

 struck by the slenderncss of the trees sometimes chosen by tha magpie ; but, 

 intelligent as this bird is, I cannot believe that it foresees that boys could not 

 climb such trees, but rather that, having chosen such a trce.it has found 

 from experience that it is a safe place. f 



Although I do not doubt that intelligence and experience often come 

 into play in the nidification of Birds, yet both often fail: a Jackdaw has 

 been seen trying in vain to get a stick through a turret window, and had 



* [A word is here accidentally omitted in the MS. — G-. J. R.] 



t For Norway, see in Mag. of Zool. and Bot., 1838, vol. ii, p. 311. For 



Scotland, Rev. J. Hall, Trare/s in Scotland, see Art. " Instinct" in Cyclop. 



of Anat. and Physiol., p. 22. For Ireland, W. Thompson, Nat. Hist, of 



Ireland, vol. ii, p. 329. For Cornwall, see Couch, Illustrations of Instinct, 



p. 213. 



