3 1 



they were round as a ball, provided with a roof, and loosely 

 composed of fine grass bents, but without feathers or hair.* 



The Siberian Willow- Wren with us, generally inhabits 

 ground which is especially favourable for the development of 

 the summer plague of Finmarken the mosquitoes. From these 

 they procure their food, and several times while the author 

 has stood still to discover the secrets of the habits of this char- 

 acteristic species by watching, it has through the mosquitoes 

 been rendered almost an impossibility. 



In the birch woods of M we meet, however, not only with 



species of purely arctic origin. Several genuine birds of passage, 

 belonging to the common European fauna, also have here their 

 furthest boundary towards the north, and the well-known notes 

 of the Garden Warbler and the Blackcap (Sylvia hortensis and S. 

 atricapilla), the Redstart (Ruticilla phcenicums), the two Fly- 

 catchers (Muscicapa atvicapilla and M. grisola), the Tree Pipit 

 (Anthus tyivialis),the Song Thrush (Turdus music us), the Hedge 

 Sparrow (Accentor modtilaris), and several others, meet us fre- 

 quently. They are the same forms here as in the south; the 

 song, however, is not quite the same ; it has a somewhat muffled 

 sound, and even a few of the strains are partly different and 

 unknown. And this allows of an easy explanation. Up here, 

 where the areas are so large and the total number of spots habit- 

 able by these species few and far between, individuals frequently 

 have no opportunity of hearing another of his own kind ; each 

 male sings only for his own mate, and competition can never arise, 

 since it but seldom hears one of the same species as itself. Each 

 one evolves his song independently of any influence from others, 

 and they thus, therefore, acquire their individual impress. 



Of other acquaintances from the lowlands, which meet us in 

 the Finmarken valley bottoms, we may mention the House 

 Martin (Chelidon urbica). In these desolate regions, this bird also 

 knows how to adapt itself to its surroundings. As in Finmarken 

 they only rarely find nesting-places on the few and low houses, 

 they therefore breed in colonies, several hundred pairs together, on 



* One of these broods is to be seen exhibited at our Zoological Museum (in 

 Christiania), all the young ones sitting by the side of each other on a branch, the 

 only young of that species that are as yet known to be exhibited. 



