NORTHERN SHORT-TAILED SHREW, Blarina brevicauda, 2021 FEBRUARY 1, WASHTENAW COUNTY, MICHIGAN, ALAN RYFF
There were two northern short-tailed shrews in the yard, one out back, the other out front. The one out back sheltered where the arching roots of white cedars collected snow-covered leaf litter. Occasionally in broad daylight the shrew broke cover and dashed some 15 feet across the inch-deep packed snow, to eat sunflower seeds fallen from an overhanging bird feeder. Doing this was indeed risky behavior. A juvenile Cooper's hawk made an appearance and perched stark still on the top of the mulberry at the far end of the yard. Meanwhile the shrew appeared as a moving dark spot on the snow. The hawk went airborne, ending its long glide with the shrew locked in its talons. It proceeded to feed while perched on the snow-covered lawn. All of this was watched from the kitchen window. Thanks to this accipiter, I lost what was to be an easy photo shoot. How often does one encounter a somewhat predictably appearing shrew in the open in daylight? The photos were to be taken from the back steps. Oh well.
Unlike the backyard shrew, the one out front was very difficult to view. A steep earthen slope descends from the porch toward the river. Embedded in the slope are rounded stones more or less of cantaloupe size. The roots of forsythias intertwine with the stones, thereby stabilizing the slope against erosion. The shrew had either a single burrow or a maze of burrows in the earth between the stones and roots. One of the shrew’s entranceways, if not the only one, was at the top of the slope and within one foot of the porch. Fallen bird seed collected around this entrance. The shrew would emerge at almost full length on its belly but keeping its hind feet and tail in the burrow. Using its teeth, it snatched a seed or two then retreated backwards into the burrow, the whole act being done as fast as snapping one's fingers twice. A minute or several would pass before this performance was repeated until the shrew presumably was satiated. No matter how long I waited with lens pre-focused and finger on the shutter, the results were either missed images of the shrew or partial images of out-of-focus fur. The above posted picture is the best I could manage. The shrew's amazing speed, I believe, was motivated by its fear of surrounding birds feeding on the seed.
The genus Blarina is endemic to the United States and Canada. It consists solely of the four species of short-tailed shrew. The northern short-tailed shrew, Blarina brevicauda, is the largest shrew in North America, averaging a hefty ¾ ounce in weight and measuring four inches in length, excluding the one-inch tail. It is the commonest shrew in the Great Lakes drainage basin. Foraging at night and to some degree on cloudy days, it consumes up to three times its weight in food daily, eating arthropods, earthworms, snails, salamanders, mice, voles, other shrews, as well as small quantities of seeds and subterranean fungi. Water availability is a necessity. Life expectancy is less than a year.
Worldwide there are 16 known species of venomous mammals. Four of these are the four species comprising the genus Blarina. The submaxillary glands secrete venomous saliva through a duct which opens at the base of the lower incisors and flows along the groove formed by the two incisors. The shrew’s bite delivers the toxin into the prey’s blood stream. It is strong enough to paralyze animals of the same size and slightly larger than the shrew. The process of paralyzing prey usually takes a few minutes. On account of its saliva and size, the northern short-tailed shrew attacks and consumes small mammals more often than other North American shrews, especially when insects are scarce. In fall and winter and during times of prey abundance, it caches up to 87% of prey, some of it paralyzed alive to be eaten later. If handling short-tailed shrews is a necessity, it is best to wear gloves. The bite can cause significant pain, inflammation and redness.
Alan
NORTHERN SHORT-TAILED SHREW, Blarina brevicauda, 2021 FEBRUARY 1, WASHTENAW COUNTY, MICHIGAN, ALAN RYFF
There were two northern short-tailed shrews in the yard, one out back, the other out front. The one out back sheltered where the arching roots of white cedars collected snow-covered leaf litter. Occasionally in broad daylight the shrew broke cover and dashed some 15 feet across the inch-deep packed snow, to eat sunflower seeds fallen from an overhanging bird feeder. Doing this was indeed risky behavior. A juvenile Cooper's hawk made an appearance and perched stark still on the top of the mulberry at the far end of the yard. Meanwhile the shrew appeared as a moving dark spot on the snow. The hawk went airborne, ending its long glide with the shrew locked in its talons. It proceeded to feed while perched on the snow-covered lawn. All of this was watched from the kitchen window. Thanks to this accipiter, I lost what was to be an easy photo shoot. How often does one encounter a somewhat predictably appearing shrew in the open in daylight? The photos were to be taken from the back steps. Oh well.
Unlike the backyard shrew, the one out front was very difficult to view. A steep earthen slope descends from the porch toward the river. Embedded in the slope are rounded stones more or less of cantaloupe size. The roots of forsythias intertwine with the stones, thereby stabilizing the slope against erosion. The shrew had either a single burrow or a maze of burrows in the earth between the stones and roots. One of the shrew’s entranceways, if not the only one, was at the top of the slope and within one foot of the porch. Fallen bird seed collected around this entrance. The shrew would emerge at almost full length on its belly but keeping its hind feet and tail in the burrow. Using its teeth, it snatched a seed or two then retreated backwards into the burrow, the whole act being done as fast as snapping one's fingers twice. A minute or several would pass before this performance was repeated until the shrew presumably was satiated. No matter how long I waited with lens pre-focused and finger on the shutter, the results were either missed images of the shrew or partial images of out-of-focus fur. The above posted picture is the best I could manage. The shrew's amazing speed, I believe, was motivated by its fear of surrounding birds feeding on the seed.
The genus Blarina is endemic to the United States and Canada. It consists solely of the four species of short-tailed shrew. The northern short-tailed shrew, Blarina brevicauda, is the largest shrew in North America, averaging a hefty ¾ ounce in weight and measuring four inches in length, excluding the one-inch tail. It is the commonest shrew in the Great Lakes drainage basin. Foraging at night and to some degree on cloudy days, it consumes up to three times its weight in food daily, eating arthropods, earthworms, snails, salamanders, mice, voles, other shrews, as well as small quantities of seeds and subterranean fungi. Water availability is a necessity. Life expectancy is less than a year.
Worldwide there are 16 known species of venomous mammals. Four of these are the four species comprising the genus Blarina. The submaxillary glands secrete venomous saliva through a duct which opens at the base of the lower incisors and flows along the groove formed by the two incisors. The shrew’s bite delivers the toxin into the prey’s blood stream. It is strong enough to paralyze animals of the same size and slightly larger than the shrew. The process of paralyzing prey usually takes a few minutes. On account of its saliva and size, the northern short-tailed shrew attacks and consumes small mammals more often than other North American shrews, especially when insects are scarce. In fall and winter and during times of prey abundance, it caches up to 87% of prey, some of it paralyzed alive to be eaten later. If handling short-tailed shrews is a necessity, it is best to wear gloves. The bite can cause significant pain, inflammation and redness.
Alan