Chestnut-Collared Longspur (IMAGE) Smithsonian National Zoological Park Caption North American grassland bird species, many endemic to the prairie ecosystem, are in decline. New research shows both cattle and bison grazing are viable options for conserving grassland birds in the prairie landscape. Credit Andy J. Boyce/Smithsonian Usage Restrictions No restrictions. License Public Domain 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.