Most species feed on invertebrates as juveniles and shift to feeding on vertebrates as adults. These are usually feeding, breeding or sheltering sites. There are facilities for baby changing and feeding. Possibilities include seasonal feeding or mating. Entire generations often migrate between one pair of feeding and nesting areas. Fish prefer to join shoals that are actively feeding. This resulted in a reduction in the interest of eating ("feeding"). Beavers maintain and defend territories, which are areas for feeding, nesting and mating. Reviews of animal feeding studies mostly found no effects. Insects have a range of mouthparts suited to their mode of feeding. Moose are the only deer that are capable of feeding underwater. Rickettsiae are transmitted to through saliva injected while a tick is feeding. There are dozens of conditions that may require tube feeding. The evidence for benefit of supplementary feeding is poor. Herbivores employ numerous types of feeding strategies.