web analytics

Tag Archive | "below zero temperatures"

Limits of Cold Tolerance


By Ranger Steve Mueller

By Ranger Steve Mueller

Mike’s water line burst in the crawl space at -23 F, Charlie and Julianne had the main water line to the house freeze at -16 F, and we had a kitchen waterline freeze. Mike replaced a 6-inch section of piping and the others, with quick attention, were thawed with no damage.

Significant below zero temperatures in the area have not occurred in 20 years. Cold air settles in the lowland at Ody Brook. During a recent week, two days experienced -15 F and another -16 F.

For wildlife the cold can be more than an inconvenience. Locally millions of animals, mostly insects, likely froze during February’s cold snap. Some survivors were probably maimed. Such events are hidden from our view. Opossums have established more northerly and we can expect frostbit, stub-tailed animals this spring unless the naked tailed animals had well protected shelters. Many opossums likely froze because they do not have a well-developed under fur and protective guard hairs like mammals better adapted to this climate.

Insect species inhabit areas with suitable climate and expand populations northward when milder climatic conditions allow. Each year Painted Lady butterflies immigrate northward, reproduce, and late season offspring succumb during winter. Other species have partial success until an extreme winter ends range expansion. Life expands, from best survival conditions in core habitat areas, to outlying fringe areas, where generations over time might develop survival adaptations to new conditions. The new local genotype adaptations get passed on to offspring.

Flowering Dogwood trees from Georgia, sold at plant nurseries in Michigan, will not be as hardy as those with local genotypes developed in a northern climate. Nursery purchasing agents probably buy appropriate plant stock but ask for stock origin when buying.

Over-wintering Giant Swallowtail butterflies spend the winter in pupae and are thought to die during Michigan winters. Most probably do but there might be exceptions. I’ve found them in some habitats year after year and not in suitable neighboring habitats. That indicates that some populations have succeeded in isolated areas. In the mid 1990’s, -30 F eliminated the Giant Swallowtail from even those limited areas. It was several years before immigrants established colonies in those areas again.

Eastern Bluebirds used nest boxes at Ody Brook but the -30 F froze a bird during the night. In the morning a survivor sharing the nest box tried to leave but its wing feathers were frozen to the dead bird and it could not break free. It was found hanging dead outside the nest box hole. I wonder if more birds had huddled in the box and survived.

Nuthatches, Brown Creepers, chickadees and many other birds spend the winter picking millions of hibernating insects from vegetation. Even one failed food-finding day could spell death and successive day failures result in starvation. Fortunately the Black-capped Chickadee has a hibernation-like torpor during the night to help it save energy and survive. Once I saw a chickadee eating a dead chickadee and it insured existence through another winter’s day.

A multitude of insects undoubtedly perished in recent cold but their bodies continue as food for other animals, fungi, bacteria, and Protozoans. Those that selected winter hibernation sites that became buried in snow have a better chance for survival. Deep snow is fortunate. The Viceroy butterfly winters as a tiny 1/8-inch long caterpillar in a curled willow leaf tied with silk to the twig. Will its nature niche adaptations developed over millennia ensure survival this year? Interestingly, Florida Viceroy genotypes have developed unique genotype adaptations to that climate and its predators.

Local aspens might not be adapted to -20 F and many could experience tree bark splitting injuries in extended cold, while those in northern Canada have adaptations to survive to -40 F. Take a walk to look for fresh splits in tree trunks and branches. They are good places to watch birds and squirrels eating sap-sickles when tree juices flow. Yes, its time for us to taste sugary sap-sickles. Any season is good for nature exploration.

Natural history questions or topic suggestions can be directed to Ranger Steve (Mueller) at odybrook@chartermi.net Ody Brook, 13010 Northland Dr, Cedar Springs, MI 49319-8433, or call 616-696-1753.

Posted in Ranger Steve's Nature NicheComments (1)


Watson Rockford
Ray Winnie
Cedar Car Co
Kent County Credit Union
Advertising Rates Brochure

Archives

Get Your Copy of The Cedar Springs Post for just $40 a year!