Male Kirtland's warbler (IMAGE) Smithsonian National Zoological Park Caption Researchers found drier winters impact the likelihood of Kirtland’s warblers surviving migration and their ability to survive the breeding season. Credit Nathan W. Cooper, Smithsonian's National Zoo and Conservation Biology Institute Usage Restrictions Photo may only be used with credit. License Original 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.