March 2008

There is more to meet the eye than one might expect in the late winter and early spring seasons in the Tetons.  Birds, among other natural wonders, provide some interesting perspectives for the naturalist within us.  While we see plenty of snow and winter, consider that resident bald eagles are already sitting on eggs and golden eagles, while fewer in numbers, are in the midst of aerial courtship displays.  And consider another winter resident in our area, the Clark's Nutcracker. A beautiful large songbird that specializes in feeding on large seeds of pine cones, this bird is a specialist in gathering and hiding (called caching) thousands of those seeds each fall in preparation of winter.  Because the Clark’s Nutcracker remembers where it stores most of these seeds, it can breed as early as January or February and feeds its nestlings from its many winter caches.  Even more interesting is the fact that Clark's Nutcracker is one of very few members of the crow family where the male incubates the eggs. For jays and crows, taking care of the eggs is for the female only. But the male nutcracker actually develops a brood patch on its chest just like the female and takes his turn keeping the eggs warm while the female goes off to get seeds out of her caches.  Again, I think of those frigid winter nights and all those nutcrackers sitting in their nests focusing on keeping those eggs warm, all the while knowing that those nutrient-rich seeds are out there.

Great Horned Owls provide another interesting perspective on winter, as most nesting pairs are already tending to nestlings by mid-March.  Knowing that Great Horned Owls typically are on eggs by mid to late February, I again think of all those mother owls sitting patiently on their eggs throughout those frigid winter nights while we are nestled in the comfort of our warm beds.  These owls, like other winter resident birds in Jackson Hole, need plenty of energy to stay warm through the winter and all year long for that matter.  And just how much energy, you may ask?  Let’s consider the food intake of the Great Horned Owl.  With an appetite of about 100 grams of food per day, the owl is likely to consume about 80 pounds (36 kilograms) of animals, almost entirely small rodents, per year.  Assuming a potential 12-year lifespan in the wild, this calculates to about 960 pounds (435 kilograms) of mice.  At 30 grams per averaged-size mouse, this is equal to about 14,500 mice consumed in a single owl’s lifetime.  Given the potential problems mice can cause to humans living in both rural and urban areas, Great Horned Owls appear to be doing their fair share to control small rodent populations.

Along with watching for the return of hundreds of species of songbirds and the enlarging leaf-buds on aspen and cottonwood trees, be on the lookout for pairs of ravens perched close together preening each other’s feathers in ritual courtship.  And remember the incredible feats of those birds that stick out the winter here in Jackson.

Look forward to seeing all of you this summer.

Respectfully,
Roger Smith