24 R. COLLETT. 
able for all game-birds. At the same time, the larvæ of a Geo- 
meter demolished the leaves of the bilberry on great stretehes 
of the country. 
During the lemming year of 1891, an abnormal increase of 
Arvicola ratticeps took place in the mountains of Gudbrands- 
dalen, whilst Mus sylvaticus was also more than usually numer- 
ous. Moreover all the mountains from Nordmöre to Trysil in 
Österdalen were full of Nyctea scandiaca, to an extent scarcely 
reached in any other year of late). Furthermore the two spe- 
cies of Lagopus were unusually numerous everywhere, and had, 
what sportsmen call, åa *golden year?” In the lowlands Myodes 
schisticolor had, at the same time, an abnormal increase in the 
forest regions to the south of the Randsfjord. 
And now, during the last prolific year 1894, when there — 
were emigrations from the mountains in Sogn, Voss, and Hard- 
anger, Arvicola amphibius appeared simultaneously in multitudes 
in some districts of the Bergen Stift (as in Tysvær), while both 
Å. gregarius and A. glareolus were more than usually numerous 
in Voss and Hardanger. Tetrao urogallus, and the two species of 
Lagopus, also are specially mentioned as having had a fruitfull 
year on the eastern side of the range of mountains. 
The multitudinous over-production of M. lemmus 18 thus due 
to causes which are mot peculiar to that species, for the same 
causes, to a greater or lesser extent, simultaneously affect many 
other species, belonging, in part, to entirely different groups (just 
as, occasionally, they may affect exclusively these other species, with- 
out touching the Myodes in the same district). 
I Concerning this species, and its appearance in the said year on the 
mountains of Gudbrandsdal, see Nyt Mag. f. Naturv. Vol. 35, p. 184 
(1893—94). 
Norsk Jæger og Fisker Forenings Tidsskrift, 20de Aarg., p. 215 
(Christiania 1991). In the report concerning the condition of the 
game in the country for the year, it says: "The cold and unusually 
late spring has not had any injurious effect on the breeding of the 
Grouse (Rype). Å confluence of favourable cireumstances has thus 
not only given the grouse a "zolden year," but also favoured their 
development, notwithstanding the lateness of the spring. 
Ne) 


i 
| 
