Predation is a common source of mortality, typically also occurring with eggs, nestlings and fledglings. Cached food is sometimes used to feed nestlings and fledglings. They also plunder nests of smaller birds, taking eggs and nestlings. The flies lay eggs in the nest including in the nestlings nostrils. Both parents share the nesting duties like incubation and feeding the nestlings. Predation of eggs and nestlings is quite common. An active nest is one in which there are eggs or nestlings. Crows and ravens have been reported eating eggs and small nestlings. Both parents incubate the eggs and raise the nestlings. Corvids are the primary threat to eggs and nestlings. Eggs and nestlings are vulnerable to many hazards. This also can be detrimental to the survival of wren nestlings. They are also known to eat bird eggs, nestlings, fruits and seeds. The males provide food for the incubating female and later the nestlings. The youngest of the three nestlings or chicks is often killed by the older siblings.