Northern Minnesota phenology report: May 2009
By John Latimer, KAXE radio, Grand Rapids
There is no place I’d rather be than northern Minnesota in May and June. The rush and rebirth of life in the fields and forests is astonishing. Birds sing from every tree, shrub, and thicket. These same perches are bursting forth with life of their own. Leaves, flowers, and fruits develop with a speed that deceives. Though they seem slow and measured the flowers and fruits race to complete their mission, which is to spread seeds to insure survival. Now is the time to walk amid all this ruckus and observe its magic.
Purple clematis blossoms drape from the shrubbery. The lovely pale purple, bell-like flowers are quite large, perhaps two and a half to three inches long. The vine climbs and twists through the understory. The plant has no tendrils to support its stems, relying on the leaf petioles to wrap around supporting structures. These petioles turn woody and remain attached to the branches even after the vine has died away.
Clematis are not plentiful. The greatest populations occur here in northeast Minnesota, though even here they are never abundant They are somewhat shade tolerant but will not grow in the darkest thickets. They prefer moist, slightly acidic soils and I find them most often in the company of aspens. Often the vines will climb on young aspen, or hazelbrush, and I have seen them draped all over downy arrowwood. From the middle of May until the end of the first week of June look for the lovely bell shaped purple flowers of the clematis. You won’t be disappointed.
While the clematis bloom the painted turtles will be wandering about search out the perfect spot to lay their eggs. Wandering is perhaps not the right word, since the gravid females often return to the same locations year after year. Open sandy sites are selected and an urn shaped chamber is dug with the hind legs. Once the chamber is completed she lays eight or nine eggs on average, though she may lay as many as twenty.
The eggs are leathery and white. They are slightly oblong averaging an inch and a quarter long by three quarters of an inch wide. The developing turtle inside takes about eighty days to mature. Many of the hatchlings will remain in the nest throughout the winter. This explains the presence of the tiny turtles found in the spring well before the females have had a chance to lay their eggs. One nest studied by scientists experienced temperatures as low as twelve degrees, yet the turtles emerged unharmed in the spring.
Another effect of temperature on developing turtle eggs is its ability to determine the sex of the embryo. If the nest is in a sunny location and the temperature climbs above eighty-four degrees most of the turtles will be female. Conversely temperatures below this mark will produce mostly males. Inventories of populations reveal a nearly one to one relationship between males and females, so the system seems to be in balance.
It is estimated that fewer than two percent of the eggs laid each year result in adult turtles. There are many critters out there searching for a meal of fresh eggs. Fox, skunks, and raccoons destroy many nests. Hatching is only the beginning of the gantlet that they must run. Crows, mink, garter snakes, fish and even larger turtles all will make a meal of these tender morsels. And if that weren’t bad enough there are all those roads to cross. Who hasn’t seen the carnage that results from inattentive drivers. For three hundred million years turtles have faced these depredations and survived. The Painted Turtle can live for forty years in the wild, so as we move into spring, and they gather on logs to bask, let’s try to give them a brake.
John Latimer is well known throughout northern Minnesota for his phenology work. He appears weekly on KAXE radio in Grand Rapids, and audio and twitter archives are available here. We hope his work will be a frequent feature on MyMinnesotaWoods. This article also appeared in the Duluth Senior Reporter. It is printed with the author’s permission.