Notes on the Mammals of Gogebic and Ontonagon Counties, Michigan, 1920 Part 2

_Overflow swamp habitat:_ Due to the rise in water-level of the lakes of the Cisco Lake chain many low areas of forest have been flooded and killed. Many of the dead trunks of these trees still remain standing, mixed with fallen and decaying logs in the water. Locally these habitats are called "overflow swamps," a name here adopted for the habitat. There is little living vegetation in these swamps, an occasional water lily being almost the only plant present. Porcupines commonly walk out on the logs of the swamp to secure the water lily leaves, and probably the mink occasionally runs over the logs in its movements along the waterways.

_Cultivated-field habitat:_ Cleared fields occur only sparingly in the regions visited, and these fields are small in size. No study of their inhabitants was made, though silver-haired bats were collected while they were flying over a small clearing in the Little Girl's Point Region.

_Edificarian habitat:_ Towns and buildings are not very common in northern Michigan. In and around a cabin on Lindsley Lake a number of deer-mice were trapped, and signs that porcupines had invaded the cabin were noted.

ANNOTATED LIST OF MAMMALS

_Condylura cristata._ Star-nosed Mole.

Tall-sedge, 2.

Two were trapped September 3 and 5, 1920, in a short, open runway in very moist soil at the edge of a small ditch running through tall sedges in a beaver meadow near Gogebic Lake, Ontonagon County.

_Sorex personatus personatus._ Masked Shrew.

Gra.s.sy-meadow, 2.

Black spruce--tamarack bog, 2.

Wet hardwood forest, 3.

Dry hardwood forest, 3.

Shrub stage, 2.

In the Cisco Lake Region in July, one was taken in a small black spruce bog, two in a narrow tongue of gra.s.s between tall sedges and sphagnum bordering Mud Lake, three in the wetter parts of the hardwood forest, and three in the upland, well-drained hardwood forest. Near Little Girl's Point in August, two were taken in a growth of shrubs in a burn.

Near Gogebic Lake, Ontonagon County, one was taken September 4 in a black spruce bog.

_Sorex richardsonii._ Richardson Shrew.

Tall-sedge, 15.

Gra.s.sy-meadow, 1.

Sphagnum bog, 1.

This species was found only in or near tall sedges growing in moist or marshy situations. In the Cisco Lake Region six were taken near Mud Lake in July. Four of these were taken in tall sedges, one in gra.s.s alongside the sedges, and one in sphagnum between the sedges and the lake. August 30 to September 5, eleven were taken in tall sedges in a beaver meadow near Gogebic Lake, Ontonagon County.

An adult female trapped at Mud Lake, July 30, contained five large embryos. There were two pairs of inguinal and one pair of abdominal mammae. Another adult female trapped in the same place, July 22, had two pairs of inguinal mammae, but no abdominal mammae were found.

The latter individual was moulting, patches of new fur having replaced the old on the top of the head midway between the ears and eyes, between the shoulders, and on the rump. The other female mentioned above, taken July 30, had nearly completed her moult.

Only two specimens have been previously recorded from Michigan, one from Alger County and the other from Chippewa County.[2]

_Neosorex pal.u.s.tris pal.u.s.tris._ Marsh Shrew, Water Shrew.

Tall-sedge, 1.

Ditch-border, 3.

September 1 a marsh shrew was trapped in the tall sedges of a beaver meadow near Gogebic Lake, Ontonagon County. Most of the body had been eaten by some carnivore. Other specimens were taken on each of the two succeeding days, and a fourth on September 5.

The first specimen taken was trapped eight feet from a tiny stream which flowed through the marshy sedges. Two of the others were taken on the muddy bank of the stream near the water's edge, and the fourth about 35 feet from the water. All were secured within a radius of 35 feet.

This species has been recorded but once previously from Michigan, from Chippewa County.[3]

_Microsorex hoyi._ Hoy Shrew.

Black spruce-tamarack bog, 1.

Wet hardwood forest, 1.

One specimen was taken July 17 at Fish-hawk Lake in a moderately wet part of the hardwood forest. Another was taken July 29 at the edge of a small black spruce bog.

_Blarina brevicauda talpoides._ Bob-tailed Shrew.

Tall-sedge, 8.

Gra.s.sy-meadow, 6.

Alder-thicket, 1.

Black ash swamp, 6.

Arbor-vitae swamp, 4.

Black spruce--tamarack bog, 1.

Wet hardwood forest, 32.

Dry hardwood forest, 8.

Shrub stage, 1.

Paper birch--aspen stage, 6.

The species is rather generally distributed, but is by far the most common in moist woods. In the Cisco Lake Region 11 were secured; in the Little Girl's Point district, 10; and near Gogebic Lake in Ontonagon County, 52. In the latter district it was the most abundant mammal species, even exceeding Peromyscus in numbers; indeed, Peromyscus was relatively uncommon in the partly swampy woods of the region, and it might be that the abundance of the bob-tailed shrews accounts for the scarcity of the deer-mice, for the shrews undoubtedly at times prey upon the mice. The specimen recorded above from the black spruce-tamarack bog was taken near Gogebic Lake in a boggy swamp, which, while dominated by black spruces, yet contained a considerable number of arbor-vitae and hemlocks.

In the wet hardwood forest near Gogebic Lake Blarina runways are exceedingly abundant, usually running along or under sticks or logs.

Commonly they are just under the leaves, but sometimes for a short distance are without covering. One old log examined was found to be honey-combed with these tunnels. The deeper runways nearly always follow down just under a tree root.

The uterus of a female taken July 10, at Fish-hawk Lake, showed a few small swellings which were identified in the field as embryos.

Unfortunately, the uterus was not preserved. No embryos were found in 26 other females taken between July 15 and September 4. In the latter part of the season fewer immature specimens were taken than earlier in the summer. These facts show that in this region the species breeds in the spring or early summer and does not usually breed again during July and August.

_Myotis lucifugus lucifugus._ Little Brown Bat.

Aerial, 15.

Nine individuals were shot while they were flying over the lakes in the Cisco Lake Region. These were taken between 8:00 and 9:00 p. m. from July 1 to August 2; but on moonlight nights bats, believed to be of this species, were seen flying as late as 10:00 p. m. At the camp near Little Girl's Point one was shot at 7:55 p. m., August 11, as it flew about over the road through the dry hardwood forest. Five others were shot at the Gogebic Lake camp as they flitted through an opening in the wet hardwood forest. These were taken between 7:30 and 7:55 p. m., August 23 to September 2; but bats almost certainly of this species appeared regularly in the evenings about 7:10 p. m.

_Lasionycteris noctivagans._ Silver-haired Bat.

Aerial, 3.

Near the Little Girl's Point camp one was shot at 7:50 p. m., August 9, and two more in the same region about 7:45 p. m., August 17. One was flying along a road through the dry hardwood forest at a height about equal to that of the tree-tops, and the others were taken in a small clearing in the same forest.

_Nycteris borealis borealis._ Red Bat.

Aerial, 2.

Two were secured near the Little Girl's Point camp at about 7:45 p. m., one August 9 and the other August 14, as they flew about over the road through the dry hardwood forest.

_Nycteris cinerea._ h.o.a.ry Bat.