Infected birds pass bacteria in their fecal droppings. "Histoplasma capsulatum" is found in soil, often associated with decaying bat guano or bird droppings. However, rodent droppings or urine of indeterminate age should always be treated as infectious. At roosting sites this fungus can thrive in accumulated droppings. This is because of the bird droppings or bird feathers. Peasants were reduced to eating tree bark and bird droppings. Nests tend to be flimsy until cemented together by droppings. Escaped raspberries frequently appear as garden weeds, spread by seeds found in bird droppings. Such animals may resemble rocks, sand, twigs, leaves, and even bird droppings (mimesis). It can also be spread through contaminated surfaces and droppings. Corrosion has been caused by bird droppings and human spitting. The worms help clean up the snail droppings. "Ficus carica" is dispersed by birds and mammals that scatter their seeds in droppings. Some look like objects in the environment such as bird droppings. They may also eat animal feed and distribute seeds through their droppings.