Age Hasn't Slowed Down This Texas Birder By Stella M. Chávez • Aug 26, 2013 TweetShareGoogle+Email At 97, bird guide Karl Haller is still teaching people about all kinds of winged creatures. Credit chemisti / Flickr NPR's Wade Goodwyn recently set out on a bird-watching adventure at Hagerman National Wildlife Refuge with veteran guide Karl Haller. Haller's 97 years old and shows no signs of giving up what he loves to do. Hear Goodwyn's tale here. TweetShareGoogle+Email Related Content Drought + Zebra Mussels = New Water Restrictions For Some N. TX Cities By BJ Austin • Apr 26, 2013 Paul Deery / flickr.com The North Texas Municipal Water District plans to initiate Stage 3 of its conservation and drought plan June 1st. Biologists Report Spread of Zebra Mussels By Shelley Kofler • Jul 18, 2012 Texas Parks and Wildlife biologists say invasive zebra mussels have spread to the Trinity River basin. Zebra Mussel DNA Found In Additional Area Lakes By Shelley Kofler • Jan 30, 2012 Biologists have found the DNA of invasive zebra mussels in six additional Texas lakes. That doesn’t mean the mussels are there, but KERA’s Shelley Kofler reports the discovery has heightened concerns. Right now Texoma is the only Texas lake known to be infested with zebra mussels and officials want to prevent their spreading. That’s why biologists became concerned when they found zebra mussel DNA in six additional lakes: Eagle Mountain, Lewisville, Ray Roberts, Arrowhead, Bridgeport and Caddo.