Many species of birds and mammals have been observed on each of the Lake Mason Refuge units. Bird watching provides opportunities to see many northern prairie grassland species such as western meadowlarks, chestnut-collared longspurs, bobolinks, and occasional prairie falcons. Long-billed curlews and upland sandpipers can also be seen in short-grass and sparse mixed-grass prairie grasslands. Black-tailed prairie dogs are present on the Refuge and provide specific habitat conditions for some bird species, such as burrowing owls, thick-billed longspurs, and occasional mountain plovers. Mule deer and pronghorn are common in most places, while elk are more elusive in their movements on the Refuge. Native predators like coyote, red fox, and badgers are secretive and not commonly seen but do provide an important ecosystem service by controlling rodent populations and thus ensuring that each ecosystem in which they're present maintains a delicate balance between predator and prey.