As I set off on the Arboretum’s Ridge Trail, a white squirrel bounds along the forest floor, then hops into a tree. Its red eyes mean that it’s a true albino — a variation of gray squirrel that occurs in about one in 100,000 squirrels. Such creatures have no dark pigments anywhere on their bodies. The lack of pigment in their eyes increases the sun’s glare and leaves their eyes susceptible to harmful effects from the sun’s rays, often causing permanent damage to their vision.
The more common leucistic variation of the gray squirrel is a result of low — not absent — pigment. Such squirrels have white (or mostly white) fur and dark eyes. On the other extreme is the melanistic morph of gray squirrel, resulting in black fur. About one in 10,000 squirrels are leucistic or melanistic.
This white squirrel spotted on the Ridge Trail has red eyes, making it a true albino, a variation of gray squirrel that occurs in about one in 100,000 squirrels.
Ragweed is one of the most common causes of seasonal allergies in the United States. The pollen grains of this plant are very light and can be blown on the wind for miles. Many people confuse goldenrod and ragweed, unfairly blaming the former for causing allergic reactions. Though both bloom around the same time, the plants actually look quite different from each other.
Ragweed's flowers are inconspicuous and greenish-yellow in color, arranged in clusters at the top of the stem. Goldenrod’s flowers are bright yellow and form dense clusters. Goldenrod is a beneficial pollinator plant, whose heavier pollen grains are not carried by the wind, making it far less of an allergen than ragweed.
Goldenrod (right) is often confused with ragweed (left), the most common cause of seasonal allergies in the U.S.
Minnesota was once home to 18 million acres of prairie, covering a third of the state from southeast to northwest. Now, just one percent of native prairie remains, most of it having been converted to farmland. Two iconic prairie grasses can be found along the Ridge Trail — big bluestem (Andropogon gerardii) and yellow prairie grass (Sorghastrum nutans). Big bluestem can grow up to eight feet tall and is easily identified by its finger-like array of spikes (some say resembling a wild turkey foot) at the tip of its stems. The base of its stem turns bluish-purple as it matures.
Big bluestem is easily identified by the array of spikes at the tip of stems that resembles a wild turkey foot.
Yellow prairie grass can also grow quite tall, with golden-brown plumes that wave in the slightest breeze. This plant is currently in bloom; close examination reveals delicate yellow stamens and feathery white styles.
Yellow prairie grass in bloom.
Non-native smooth brome also grows along the trail. This European import has been widely planted as forage and along roadsides for erosion control, but it has spread into natural areas and tends to crowd out native species.
Smooth brome is a non-native grass that has been widely planted along roadsides for erosion control.
An eastern wood-pewee perches on a branch, singing its distinctive “pee-a-wee” call. Another, more distant pewee is also singing. Their songs are commonly heard in our Minnesota forests in the summer. These birds breed throughout the eastern half of the U.S., then migrate to South America for the winter.
The call of the eastern wood-pewee is commonly heard in Minnesota forests in the summer.
On this lovely day I encounter only two other hikers on the Ridge Trail. If you’re looking for a quiet, nature-filled walk at the Arboretum, check out this and the other East Side Trails.
The Arboretum’s East Side Trails system provides visitors with numerous hikes, including a paved .9 mile walk to the Farm at the Arb.
Holly Einess is a Minnesota Master Naturalist Volunteer. More information about the program is available on the Minnesota Master Naturalist website.