110 



The Canadian Field-Naturalist. 



[Vol. XXXV. 



are neither so numerous nor well defined, 

 however, as those I have seen in the east 

 and north, where oftentimes the natural 

 meadows were perfect labyrinths of in- 

 terlacing trails, and vegetation and muck 

 were irreparably united in highways of 

 unusual foulness. 



Measurements of drummondii collected 

 at I slay, Alberta. 



Sex Length Tail H. Foot 



Adult, Female .... 150 35 18 



Adult, Male .... 140 35 17 



Adol., Male 127 30 16 



Juv., Male - 112 27 17 



Juv., Male 95 20 16 



Least Upland Vole. 

 Microtus minor (Merriam). 



To me the discovery of this mouse was 

 of more than ordinary pleasure ; not me- 

 reh' because of its comparative rarity or 

 its ne-waiess to me, but also because of the 

 conditions it represented. It is not con- 

 fined to dank bottomlands like drummon- 

 dii but climbs to the racy pastures far 

 above. It loves the prairie crests and its 

 spicj^ winds, the flowing undulations of 

 fragrant herbage, and the rustle of the 

 wolf-willow. In the very expression 'up- 

 land ' one feels a subtle suggestiveness that 

 floats the mind instinctively to the lonely 

 north, the north with its glamour of 

 brooding plateaus, its silent and immut- 

 able tundras. 



At Islay the upland vole casually occu- 

 pies the lusher kwlands, not much in ele- 

 vation above drummondii, but always, so 

 far as I could learn, on ground never sub- 

 ject to inundation, which is distinct from 

 that of the latter. The local habitat of the 

 two, if not actually overlapping, certainly 

 is subject to a very fine delimitation. In 

 the matted grass of willow-grown but 

 elevated flats it is as likely to be found 

 as anywhere, although its presence is by 

 no means as certain as the other species. 

 When finally located its sparse trails will 

 be found leading languidly among the 

 willows, rose bushes, and herbage; tun- 

 neled through the latter rather than over; 

 fashioned round without a break for con- 

 siderable distances. On the slopes or in 

 creases of the prairie it lurks in grassy 

 tangles beneath wolf-willow and aspen, and 

 at times, as previously mentioned, turns to 

 the very crest of ridges that are gilded with 

 the first and last lights of dawn and sun- 

 set. 



Unlike the vexing separation of many 

 members of this genus, the present voles 

 are palpably distinct ; with the two side by 

 side, colour difference alone suffices to 

 separate them. Drummondii, heavy set, 

 and of a reddish-grey colour, contrasts 

 clearly with the slighter build and 

 silvery-grey of minor. For a time, while 

 trapping, the occurrence of these two 

 colorations, which I distinguished from 

 the first, proved rather puzzling. Hav- 

 ing no literature along led me er- 

 roneously to imagine it a seasonal pliase 

 on the same species. In trapping, however, 

 I noticed that each 'phase' singularly 

 api^eared separate, which led me very 

 early to suspect the truth, as is 

 shown in this journal entry : Sep- 

 tember 26 "A second specimen to- 

 night of the grey microtus, both from the 

 same trap. It would appear that this ani- 

 mal is perhaps a distinct variety from. the 

 reddish-grey vole. At any rate a cursory 

 examination of the few microtus taken 

 here suggests this ; ' ' and again for Septem- 

 ber 27, I find in part this note: ''Succeed- 

 ed in capturing another silvery-grey vole. 

 Reference was made to this animal on both 

 the 24th and 26th. This one of to-day as 

 well as the others were all taken in the 

 same trap and locality and only at a slight 

 elevation and distance from the lower 

 ground where I succeed in collecting only 

 the'brownish voles. ' ' 



Islay is close to the northern limit of its 

 range. 



Measurements of Islay specimens of 

 microtus minor : 

 Sex Length Tail Foot 



Male 110 IS 14 



Male 115 IT 15 



Female 115 .23 14 



Female 108 IT 15 



Female 116 22 15 



Baird's Masked Shrew. 



Sorex {iersonatus haydeni (Baird). 



Only two of this diminutive and rather 

 obscure animal were collected at Islaj^. 

 Both were taken, in the same trap and in 

 tlie same damp lowland where most of my 

 drummond voles were captured. Tliey 

 appear to be rather uncommon. A plains- 

 man told me that in passing low places at 

 night he had frequently seen these shrews 

 darting across the trail under the glare of /iQ 

 the head-light on his car. The two speci^jSi 

 mens secured are noticeably smaller than / 



M 



