NATURE HAPPENINGS - January 2004

Winter in the Wetlands
by Damian Fagan

The quiet is deafening. I stop often along the boardwalk trail, for the crunching of old snow beneath my boots makes too much noise. I can’t hear the birds sing, but then again, not many are singing this time of year. Silence floods the void; even the not-to-distant highway is silent. You just have to love January here in the wetlands.

A husky whit interrupts my reality. Though I know the call note by heart, I still scan the trees until I locate the tiny yellow-rumped warbler flitting amongst the branches in the tall cottonwood tree. Appropriately named, I catch a flash of yellow as the bird works over the twigs and buds of the cottonwood, picking off tiny insects that somehow withstand this cold. Though it seems unusual to have a wintering warbler – most of the yellow-rump’s relatives spend the cold months in more southern climates – this species is a fairly common winter sighting in the Matheson Preserve.

As I continue around the loop, the bird activity increases. Dozens of American robins, dressed in their orange finery, descend into a Russian olive tree and begin to gorge themselves on seeds. The fruits are in abundance and the robins consume the fruits, pits and all. I almost want to shout at the birds, scare them from the tree, for I know that their droppings will help to spread these unwanted exotic trees. The olives invade areas where native plants could get established, and though some wildlife forages on the fruits, research has shown a lower diversity of wildlife species occur in Russian olive dominated habitats versus in native habitats. Unfortunately, the olive, like tamarisk, is a successful colonizer of disturbed areas and tends to grow in proliferation.

Farther along the boardwalk I run into the seeds again, this time encased in the scats of a raccoon or maybe even a gray fox. The highly striated seeds of the olive are easy to discern. My scatological investigation is interrupted by the raucous calls of the robins as a heat-seeking Cooper’s hawk blasts through the grove. The robins scatter like gossip, momentarily confusing the hawk. But the bird must see something it likes, for it continues on in hot pursuit.

I can’t see the finish line and whether or not the Coop collects a prize. Success means survival, and the abundance of prey here is an attraction that draws many predators. The smaller relative of the Cooper’s hawk is the sharp-shinned hawk. Named for its bony legs, the sharp-shinned also prowls the preserve in search of smaller prey like yellow-rumps, house finches or juncos. Unlike the soaring hawks or buteos that often hunt from an aerial vantage, the sharpie and Coop are built for quick pursuit and navigating through thickets of vegetation. With short, broad wings and rudder-like tails, these accipiters hunt the woodlands while other hawks, like the harrier, take to the open fields.

Formerly known as the marsh hawk, the northern harrier quarters over the bulrushes and grassy fields in search of sparrows or small rodents. With an owl-like facial disk, the harrier has exceptional hearing abilities, which aids in its hunting. After locating a sound, these hawks pull up and hover over the area before descending talons outstretched. Like the sharp-shinned hawk, northern harriers are often observed in the preserve in winter, but they migrate northward once spring rolls around.

Though I strike out on the harrier today, I do catch a bald eagle soaring over the Central Pond. Portrayed as a fierce predator, our nation’s symbol often resorts to piracy or feeding off carrion to survive the winter. This behavior may be related to the bird’s preference for watery habitats that tend to freeze over, thus forcing the bird to shift from a fish-based diet to one of feathers or fur.

This particular bird is an adult with its unmistakable white head and tail contrasting with the chocolate brown wings. Carving wide circles into the deep blue sky, the bird climbs in altitude and is soon gone from view.
I add this sighting to my list which stands at twenty-eight species. The different habitats in the preserve attract a diversity of bird life. From dark-eyed juncos and white-crowned sparrows to wood ducks and buffleheads to Cooper’s hawks and northern harriers, and all may be observed within close proximity to town.

Later on, I leave the preserve under the shadow of cold. Still early in the afternoon, the high cliffs block out the winter sun. With the darkness comes the companionship of quiet that once again descends over the preserve. Only my heavy footfalls disturb the peace. Winter in the wetlands exaggerates the dynamic character of this place, accentuating its seasonal appeal to both bird and birder.