The San Joaquin River and its marshes and wetlands provide a critical resting and breeding stop for migratory birds along the Pacific Flyway. Once, the seasonal bird populations in the San Joaquin basin were immense, especially in the now-dry Tulare Lake region: "It took something different, though, to capture the sound of the blue sky as it turned dark and deafening from the wings and cries of millions of native and migratory birds – Canada geese, mallards, swans, pelicans, cranes, teal, and curlews. How to mimic the sudden flight of flocks so immense they extinguished the sun? One of the first white men to camp along the lake could think of only one noise, the roar of a freight train, that compared with the takeoff of the birds." Historically, the grasslands and the fringes of the great marshes and lakes provided habitat for large grazing animals including pronghorn, mule deer and the endemic tule elk, as well as predators such as the San Joaquin kit fox; all of these species have seen dramatic population declines as their native habitat has fallen under the plow.