This can cause a nest like a Wren , or smaller species to starve their own young~

These birds are well heard of around here for their bad habit of being a brood parasite... They will lay their eggs in the nest of other birds to be raised by them.  This can cause a nest like a Wren , or smaller species to starve their own young, to keep up the pace of the needs of the Cowbird~
*The darker birds are the males and the lighter phase is the female...