ENHS Nature Trails March 2003 Article 3

Wetlands
by Reida Kimmel

Our little farm, much of which is a wetland, is running with water. Yesterday, out in the tule grasses to the west of the pond there were more that twenty robins feeding, probably on the earth worms that were surfacing to get oxygen. The big creek in the woods by the road is just booming with water going over the falls and rocks. In those woods I have recently seen four varied thrushes calling and jumping from branch to branch in a small fir tree. Now Oregon grape is about to bloom at the edge of the trees, and deeper in the shade, the fawn lily leaves are large and glossy. Trace one of the ephemeral creeks back through the sheep's hill pasture and you will find a very wet path with many branches. Here trillium and wild ginger are just starting to bloom. It is an early spring. Newts, mostly females, are on the move down to the pond, where there are already many egg masses laid by Hyla, whose calls fill the air every evening now. A red winged blackbird is calling for a mate in the tattered remains of last year's bulrushes. I love the wet, even if it means that my knees are always getting sopping whenever I weed or plant something. I have to admit I rather dread the long soggy crawls that will accompany next week's potato and onion planting but still, I hope for a very wet and cool spring. The earth needs it.

Yet, with the West Nile Virus already in Oregon, is it irresponsible to hope for damp weather into the summer? The horses have been inoculated. I don't think about the remote possibility that the virus would infect myself or my family. The virus, as Lauren Coggins of the Cascade Raptor Center reminded me the other day, is a bird virus. Its primary victims are birds, not humans. There's an interesting summary of the state of research on the virus in birds in the Journal Science, February 23, 2003. In "Researchers Scramble to Track Virus's Impact on Wildlife," David Malakoff stresses that the science of the disease's epidemiology is lagging because the government has been slow to fund research. The virus has spread farther and faster than anyone could have predicted. It, or antibodies to it, have been found in 157 species of birds, 37 kinds of mosquitoes and 18 species of vertebrates. It has spread to 44 of the contiguous 48 states and to 6 Canadian provinces. An early theory held that the virus was spread by migrating birds, but so far no migrating bird has been found to be carrying the virus. Crows and other corvids are the most susceptible. One great problem in tracking the spread of the disease so far is that once the disease is found in an area, health officials stop testing for the virus. Of 125, 000 dead birds turned into the CDC, only 32,000 were actually tested. Of these, half were positive. We need to get a clear picture of what the disease is actually doing to bird populations and that takes research.

Laura Coggins had some very bleak things to say in our conversation the other day. She predicted that here, as in the rest of the nation, ravens, jays and crows would be very hard hit by the disease. Understandably, the folks at the Cascade Raptor Center are most worried about the hawks, owls, and eagles that they care for. Of the very large number of dead raptors turned in and tested for the virus in other parts of the country last summer, all had tested positive. Sick birds in rehabilitation had suffered 100% mortality. Nevertheless, it is so important that we in the community do not panic. We should resist community efforts to do mass spraying because the insecticides harm beneficial insects too. Birds, amphibians and other invertebrates are the natural controlling mechanism of mosquito populations.

Here on the farm, mosquitoes hatched in the pond will feed our swallows. The larvae will feed young Hyla, newts and Ambistoma gracile as well as those big scary dragonfly larvae. I will be sure to dump and clean the sheep and horse water buckets weekly and to see that the "very useful" old tires we have about the corral's periphery have holes cut on their undersides so they cannot hold water. In a sense, I will be the predator in the unnatural situations that I have created. If you have pools and water in your garden, think of installing a pump, and creating a fountain. Birds love to bathe in the running water, and mosquitoes prefer to breed in still water. Nonnative "mosquito fish" so popular with many gardeners, are really not a good idea. They are voracious predators on young amphibians and other native species. If there is any chance that your mosquito fish could escape into the greater ecosystem, or if you wish to encourage native frogs and newts in your pool, get rid of your mosquito fish. "Feeder" goldfish also eat mosquito larva and are far more benign. Above all, avoid introducing bullfrogs, as they are a huge threat to our native amphibians all over the Northwest. Enjoy your garden, no matter how wet. Do your part, no matter how humble, to help our native vertebrates by creating and enhancing niches for their survival.

Editor's Note: Bull Frogs were brought to this country for their delicious legs. We cold help our native amphibious and reptilian populations (Bull Frogs are notorious predators of the Western Pond Turtle's eggs) and enjoy a culinary delicacy.

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