Notes on the Mammals of Gogebic and Ontonagon Counties, Michigan Part 4

In the Cisco Lake Region and in the vicinity of Little Girl's Point this species is the most abundant mammal, but in the wet woods at the Gogebic Lake camp it is much less abundant, being exceeded in numbers by the bob-tailed shrew. A total of 308 deer-mice were taken during the summer. It was found in a variety of forest habitats, but it is most abundant in the dry upland woods of the Little Girl's Point Region. The individuals taken in the tall sedges at Mud Lake were probably stragglers from the nearby shrubs and forest, for no deer-mice were taken in the extensive sedges of the large beaver meadow studied near Gogebic Lake. Probably most of those taken in the black spruce bogs were stragglers also, though one individual taken in a large black spruce bog was 50 yards from the nearest deciduous woods.

When we arrived in the Cisco Lake Region in late June young and subadults were abundant, many of the female subadults, as well as the adults, carrying embryos. Embryos were found throughout the summer up to August 25. Of females containing embryos, five had 4 embryos each, ten females 5 embryos each, nine females 6 embryos each, and one female 8 embryos.

_Synaptomys cooperi fatuus._ Lemming-vole.

Tall-sedge, 1.

Black spruce--tamarack bog, 2.

Wet hardwood forest, 1.

Dry hardwood forest, 1.

In the Cisco Lake Region an adult female was taken in dry hardwood forest near Fish-hawk Lake June 28, 1920. It contained 6 embryos each 21 mm. long. A juvenile was trapped July 26 on top a log in the tall sedges at Mud Lake. The log bridged over a particularly wet part of the marshy sedges and was at the edge of the hardwood forest. Two other juveniles were taken the next day, one in a small black spruce log, and the other in wet hardwood forest at the edge of the same bog. In Ontonagon County near Gogebic Lake a subadult male was taken September 5 in a large black spruce bog.

_Evotomys gapperi gapperi._ Red-backed vole.

Black ash swamp, 2.

Black spruce--tamarack bog, 6.

Arbor-vitae swamp, 2.

Hemlock forest, 5.

White pine forest, 2.

Wet hardwood forest, 18.

Dry hardwood forest, 17.

Shrub stage, 5.

Paper birch--aspen stage, 3.

Thirty were taken in the Cisco Lake Region, 10 at the Little Girl's Point camp, and 20 near Gogebic Lake in Ontonagon County. It was most common in the forests. Two individuals recorded from the arbor-vitae swamp were taken in a mixed swamp of small arbor-vitae, black spruce, and hemlock with many alders, this situation probably forming a stage in the succession following a beaver meadow. Also, one of the specimens recorded from the paper birch--aspen stage was taken in an open stand of old paper birches with a forest floor of gra.s.s, conditions not typical of the stage.

Of 13 females examined from June to August, two contained 4 embryos each, two 5 embryos each, and two 6 embryos each. August 14, at Little Girl's Point, was the last date on which embryos were found.

The species is somewhat diurnal. Several times one was seen in daylight about the camp in the Cisco Lake Region, and several were trapped during daylight hours.

A captive was fond of tender gra.s.s blades, but refused the harder stems. In eating he sat up on the hind feet and handled the food with the fore feet.

An immature male taken August 8 near Little Girl's Point had a considerable infestation of seed ticks on the posterior lobes of both ears.

_Microtus pennsylvanicus pennsylvanicus._ Meadow vole.

Mud-flat, 6.

Tall-sedge, 28.

Gra.s.sy-meadow, 6.

Black ash swamp, 1.

Arbor-vitae swamp, 1.

Leather leaf bog, 15.

Sphagnum bog, 9.

Black spruce--tamarack bog, 1.

Shrub stage, 17.

Sixty-five were taken in the Cisco Lake Region and 19 in Ontonagon County, near Gogebic Lake. It is most abundant in gra.s.sy and sedgy meadows and in open bogs, though it is found rarely in swamps and tree-covered bogs. The individual listed from the arbor-vitae swamp was taken in a young growth of arbor-vitae, black spruce, hemlock, and many alders, and not in typical arbor-vitae swamp habitat. Of the 17 listed from the shrub stage, one was taken in a wet, sedgy part of a shrub-covered burn at Poor Lake, and the others were secured in the shrub and gra.s.s clearing around the camp house on Lindsley Lake.

Of ten females examined, July 10 to September 5, one contained 3 embryos, one 4 embryos, and two 5 embryos each. September 5 was the last date on which embryos were found. The three embryos found on the last date were each 23 mm. in length and together they weighed 8.5 grams, which was 26 per cent of the weight of the mother with the embryos removed.

Both adults and immature young were seen moving about, and were also trapped in broad daylight, but it is more active in the evening just before sunset.

A captive juvenile was placed July 19 in a large tub with an adult female, which might have been its mother, for both were taken on succeeding days in the same trap. The young one immediately tried to nurse, but was severely bitten and driven away, though it made numerous unsuccessful attempts later. When approaching the old female the baby frequently gave a high-pitched squeak, and the old female replied by a hoa.r.s.e squeak, evidently of warning, for the young one was bitten when it approached in defiance of the warning note and threatening att.i.tude of the adult. The baby evidently had been weaned, and the old female was found to contain five large embryos.

_Ondatra zibethica zibethica._ Muskrat.

Forest--sh.o.r.e, 5.

Water lily, 1.

Pondweed, 2.

Willow-thicket, signs.

Muskrats are numerous in the Cisco Lake Region, and five specimens were taken. Near Little Girl's Point one was seen swimming in a small stream. At the mouth of Merriweather Creek on Gogebic Lake signs were noted in a willow thicket, and muskrats were reported numerous in the region.

An adult female trapped July 6 at Fish-hawk Lake contained six large embryos; another female taken July 10 contained no embryos, but the mammae were filled with milk; and two females taken July 26 contained no embryos.

In the Cisco Lake Region broken mussel sh.e.l.ls were abundant in the muskrat runways along the sh.o.r.es. Remains of pondweeds were also frequently found in the runways, and a quant.i.ty of leaves with a few heads containing flowers and seeds collected July 8 were identified by E. A. Bessey as _Potamogeton richardsonii_.

_Zapus hudsonius hudsonius._ Jumping-mouse.

Mud-flat, 4.

Tall-sedge, 12.

Gra.s.sy-meadow, 8, Arbor-vitae swamp, 1.

Sphagnum bog, 1.

Black spruce--tamarack bog, 1.

Wet hardwood forest, 2.

Dry hardwood forest, 1.

Shrub stage, 10.

Paper birch--aspen stage, 2.

Numerous in suitable habitats in the Cisco Lake Region, at Little Girl's Point, and at Gogebic Lake. Most common in open gra.s.ses and sedges. Five of those recorded above from the shrub stage were taken in open shrubs and gra.s.s in the clearing around the camp house on Lindsley Lake; and the two recorded from the paper birch--aspen stage were taken at Cisco Lake in an open stand of old paper birch with a forest floor of gra.s.s.

Juveniles were taken throughout the summer, but no one of seven adult or nearly adult females examined between July 7 and September 4 contained embryos.

A captive taken July 18, after feeding ravenously on a cooky, retired to a corner and went to sleep. The position taken in this case was a sitting one, the animal resting on the widely spread feet as far as the heels, and on the tail. The head was bent far over, the nose extending between the hind legs. The long tail was curled around the body, it resting on the ground for its whole length. The operation of cleaning the tail was observed two days later. The animal worked from the base of the tail toward the tip, using the fore feet to present the tail to the mouth, where it was licked off. During the process the head was held over on one side, nearly touching the ground.

_Napaeozapus insignis fructecta.n.u.s._ Woodland Jumping Mouse.

Wet hardwood forest, 1.

Dry hardwood forest, 6.

Three were taken in the Cisco Lake Region and four in the Little Girl's Point Region, all in heavy forest.

Neither of two adult females taken August 8 and 10 contained embryos.

_Erethizon dorsatum dorsatum._ Porcupine.

Forest--sh.o.r.e, 13.

Wet hardwood forest, 10.

Dry hardwood forest, 17.