Natural Selections: Jeff Mitton: Nylon hedgehog cactus stirs controversy among biologists
While walking along the Coalton Trail through Boulder County Open Space I noticed some small cacti in flower.
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Jeff Mitton: Natural Selections: Broad-tailed hummingbirds need to return to Colorado sooner
Male broad-tailed hummingbirds, Selasphorus platycercus, arrived first, and they immediately got down to business.
Jeff Mitton: Natural Selections: Wild burros on the San Rafael Swell
A few miles south of the historic swinging bridge crossing the San Rafael River, a group of 10 burros grazed on a rolling plain.
Natural Selections: Jeff Mitton: Reakirt’s blue caterpillars act in ancient mutualism with ants
Reakirt's blue butterflies were moving among the flowerheads of white clover in my lawn. I presumed that they were nectaring, but I watched closely and discovered that they were ovipositing.
Natural Selections: Jeff Mitton: Stork’s bill seeds plant themselves
Common stork's bill — or redstem filaree, Erodium circutarium — is flowering now on the plains and in the foothills. Its blooms are small, just 10 to 15 mm across.
Natural Selections: Conflict and vigilance among red-winged blackbirds
From the branch above me, a male red-winged blackbird took a deep breath, hunched up his shoulders, flared the feathers on his epaulets and let out a loud threat directed...
Natural Selections: Elm leaf beetles are just one of the introduced species that suppress American elms
American elms, Ulmus americana, are native to North America from Saskatchewan to Nova Scotia and from Texas to Florida. They grow 60 to 80 feet tall, with a thick trunk,...
Natural Selections: Salt and pepper adds spice to spring
In March and April of each year I get anxious for the arrival of spring. I watch the days get longer and visit a variety of sites in Colorado and...
Natural Selections: Tiger whiptail lizards come in many forms
A long, slender lizard moved among trees in a pinyon-juniper woodland on the Colorado Plateau, searching the accumulated debris beneath the trees for grubs, spiders, beetles or any other insects....
Natural Selections: Why do leopard frogs come in two colors?
I camped at Teal Lake in the Park Range to photograph fall colors, but I also enjoyed the ospreys that were hunting trout and the numerous leopard frogs at the...