In certain ecosystems, such as the 41,000-acre Cheyenne Bottoms wetlands in Kansas, chironomid larvae are particularly abundant. As many as 50 of the creatures may inhabit a single square inch of mud, providing ample fuel for the large numbers of birds that visit the area during spring migration. Yet, some locales are not so fortunate. Aerially sprayed insecticides eliminate large numbers of chironomids, as well as mosquitoes and other disease-vector insects at which they are targeted.