Horned Larks 2 (IMAGE) Field Museum Caption Horned Larks from The Field Museum's collections, with gray bird from the turn of the century and cleaner bird from more recent years when there was less soot in the atmosphere. Credit (c) Carl Fuldner and Shane DuBay, The University of Chicago and The Field Museum Usage Restrictions Please include credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.