Ravens were once a rarity in the North Country, but now they are becoming a common sight. They have a similar appearance to crows, but if you see the two birds together the difference is obvious. For one thing, ravens are big. For another, crows caw, while the cry of a raven is more of a croak.Martha Foley and Curt Stager discuss other ways to tell the two apart, why ravens became a scarce presence in recent times, and why they might be making a comeback now.

For decades, Adirondack resource managers have blamed the yellow perch for the decline of heritage trout strains, believing that perch were introduced to Adirondack waters in recent times and have been displacing the native strains from their historic habitat.But lake sediment core samples taken by Curt Stager and his students at Paul Smiths College yield DNA evidence showing that trout have been co-existing with perch for at least 2,000 years there. While perch are aggressive competitors and native trout are in decline, the reason for the change in balance likely lies in other factors yet to be determined.

When species move into a new habitat, some of the "tricks" their genes have learned no longer work to help them thrive. Some species will pick up new tricks - sometimes the same new trick more than once - and some will fail to adapt. Martha Foley and Curt Stager look at silent crickets and flightless birds.

What we call reindeer moss is nothing of the kind. It's not even a plant; it's a lichen. Lichens, which account for half of the natural nitrogen fertilizer used by plants and animals, are a combination of a fungus colony with algae and cyanobacteria that can live on practically nothing - dust, pollen, rain and snow.Martha Foley and Curt Stager talk about nature's original minimalists.

Social primates are supposed to share when they find food, but some will cheat. If they are caught, the group will punish them. Some plants and fungi use a kind of barter system to swap nutrients, and some of them will also cheat. But they risk being caught and cut off.Martha Foley and Curt Stager look at crime and punishment in the natural world.

Ferns invented nectar - a sugary reward - long before flowering plants evolved. But instead of using it to attract pollinators, the bracken fern uses it as "protection money," paying off ants and other predatory insects that will keep voracious caterpillars away when the plants are young and vulnerable.Martha Foley and Curt Stager unveil the mobster economics of nature.

Ferns invented nectar - a sugary reward - long before flowering plants evolved. But instead of using it to attract pollinators, the bracken fern uses it as "protection money," paying off ants and other predatory insects that will keep voracious caterpillars away when the plants are young and vulnerable.Martha Foley and Curt Stager unveil the mobster economics of nature.

Dr. Curt Stager took students to Walden Pond, the retreat of philosopher and citizen scientist Henry David Thoreau, to take sediment samples and compare modern observations with the meticulous records kept in Thoreau's journals.They found evidence of a changing climate and a lake ecology that has been altered by human use. The graphic novel that records the expedition might have bemused and amused the famed transcendentalist. Curt talks about the work with Martha Foley.

The red fox isn't always red. The silver fox, for example, is the same species. But they will usually have a white tail tip and always wear black "boots." You can find the red fox pretty much everywhere, from the North Country back yard to the Australian Outback.

The gray fox has been in North America for millions of years, but the more common red fox is a relative newcomer, crossing over during more recent Ice Ages. The two kinds of fox are not only different species, they do not even belong to the same genus.Besides differing in color and aggressiveness, the gray fox has semi-retractable claws that allow it climb trees to escape from predators. Martha Foley and Dr. Curt Stager discuss the slyer end of the canid family.As a bonus see the video below of baby gray foxes that live under Joel Hurd's barn in Pierrepont.