Dave Anderson looks at how animals (humans too), insects and plants get their cues for winter preparation.

"First frosts" trigger an instinctive impulse to get busy. With cool weather, people become more focused and task-oriented. There is no shortage of domestic chores: stowing summer clothes and finding the winter wardrobe, canning and jarring, pulling vegetable gardens and mulching perennial beds. By October, the urge to rake leaves or stack cordwood is particularly acute.

Wildlife also seem to respond to the onset of cool weather. In reality, gradually falling levels of daylight since mid-summer influence hormones that trigger changes in plant metabolism and animal behavior.

Birds migrate south. Mammals feed heavily to build fat reserves. Rodents squirrel-away seeds and nuts in their dens while beavers build a cache of hardwood branches to sustain them beneath the ice.

Amphibians and reptiles retreat to pond mud or burrows beneath frost line. Turtles can absorb oxygen from water through their nostrils. Frogs and salamanders do the same through their skin. Fish restrict movement and retreat to deep, slow water to avoid ice scouring in shallow streams.

Insect eggs and larval caterpillars beneath tree bark may await hatching or metamorphosis next spring. For many insects, winter brings death.

Diminished daylight triggers plant shutdowns. Hormones that regulate growth, flowering, seed development and fruit ripening are influenced by relative levels of light and dark. Decreased daylight stimulates production of hormones that initiate autumn leaf fall and formation of waxy buds to protect tender tissue against the drying effects of cold during winter dormancy.

Plants and animals must effectively measure light. If "first frost" were also the first clue to approaching winter, there wouldn't be ample time to prepare.