:370 MENTAL EVOLUTION IN ANBIALS. 



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

 habits of H.fidva 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 makes its nest to match with surrounding 

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

 wljen we hear from White (Letter 14) 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. Keithei 

 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 ^ 

 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), liave been known regulni'ly to build in rabbit-burrow a. 

 Numerous analogous facts could be given. The Water-hen {G. chloropus) vs 

 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 thai 

 this was never done. Water-hens and Swans, w^hich 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. Yarrell 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 iinder the eaves of houses, as well as in ti-ees. 

 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 would 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 slenderness of the trees sometimes chosen by the magpie ; but, 

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

 climb such trees, but rather that, having chosen such a tree, 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 omitt(Kl in the MS. — Gr. J. R.] 



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



Scotland, Rev. J. Hall, Travels in Scotland, see Art. " Instinct" in Cyclop. 



of Aiiat. and Phi/sioL, p. 22. For Ireland, W. Thompson, Nat. Hist, of 



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



p. 213. 



