The chosen site is along the river, next to the Wawona golf course. The first order of business is to set up the mist nets. Running my fingers along its tough, lacy fabric, it reminds me of reinforced hair netting. Mist netting is an important means of surveying the bat population because it provides in-hand observations, but a night's catch is not a representative sample of the bat population. The mist net will be stretched across the river to catch the bats which use the South Fork as a fly way in their nightly pursuit of prey.
Bats use a unique method of locating their prey called echolocation.
Emitting high frequency pulses and listening for the echo bouncing back, they are able to detect flying insects such as moths and mosquitoes. Bats have a voracious appetite, with some species catching their body weight in insects every night Five sixty-foot nets are stretched about one foot above the water. Four of the five nets reach two meters above the water. The final one is stretched three meters in hopes of capturing the elusive Eumops perotis , which tends to fly higher than other species. Commonly called the Greater Mastiff Bat, Eumops is the largest bat found in North America.