An Iowa bird expert says he’s -not- concerned about a study that predicts global warming will eventually erase Iowa’s state bird from Iowa’s skies. Doug Harr, a wildlife diversity biologist at the Iowa Department of Natural Resources, says the eastern goldfinch is -not- endangered or threatened.Harr says a study done during the 70s and 80s found a slight nationwide decline in the goldfinch population, but he blames that on improved herbicides which control seeds from weeds which the birds like to eat.A study released this week from the National Wildlife Federation says the eastern goldfinch and several other birds are changing migration patterns because global warming is altering their habitats. It predicts finches will be gone by the year 2100. Harr says population changes would more likely be caused by altering the birds’ food supply, not global warming. The birds feed on thistle seeds.Harr acknowledges the goldfinch “might be in a little bit of jeopardy over the long haul.” He says as Iowa was settled, the finch population rose as the birds thrived on the European thistle seeds. Only when farmers learned to better kill those weeds, did a finch decline start to appear.