Himalayan blackberry

Alien berries may not be best for birds

Although winter fruit-eating birds may be feasting now, alien or non-native berry-producing plants may not be the best thing for birds in the long term.

The fruits of non-natives like cotoneasters, Pyracantha, European mountain ashes, Himalayan blackberries, and English holly, laurel, ivy, and yews might be enjoyed by robins, waxwings, starlings and other birds. But the spread of these plants displaces native vegetation that ultimately supports a greater diversity of wildlife.

That idea was recently expressed by West Seattle ecological consultant Stewart Wechsler in birding e-mail exchanges, and supported by WDFW wildlife biologist Russell Link.

“In the long term, after the (birds) sprinkle the seeds all over the landscape with little packets of fertilizer, these alien shrubs and trees replace the native plants, and in turn displace the other native organisms best adapted to living with those native plants, and we get less biodiversity,” Wechsler wrote. “This most likely includes fewer of some of the very bird species that eat these berries.”

The interconnections are complex. Wechsler explained most song birds primarily feed their young moth and butterfly caterpillars, which grow on specific native host plants. If those host plants are displaced by non-native plants, there’s less food for young birds. Whether adult resident or migratory birds use winter berries or not, this decline in forage for young ultimately leads to a decline in birds.

Wechsler advocates pulling up existing non-native plants and replacing them with native fall and winter berry-producers, which include Douglas (black) hawthorn, blue elderberry, Pacific crabapple, bald-hip rose, evergreen huckleberry, tall Oregon grape, salal, and western serviceberry.