HIMMMMMM, I am thinking of Crows, thanks to Agatha Christie and Ngo. The correct term for a group of Crows is not a flock but a MURDER of Crows. Very complacated pattern of society in their world, much like that of the humans. If a member of the group acts up, all the crows surround the culprit and like a jury discuss the problem. Then they as a group kill the bad Crow.
Cookcoo bird will find a nest of eggs, fly in, kill the eggs and lay their own eggs in the nest for the unsuspecting mom and dad to raise. -----Old days the term was used for a father whose wife led him to believe the children were his.
Male lions will fight to the death for the females, When the older lion dies the new leader comes in and kills all the cubs of the father in order to pass his and only his DNA on to the next batch of cubs. Today we see this behavior in men that kill their step children or children of their girlfriends. In some cases it is the wicked step mother that harms her husband/boyfriends kids from a previous relationship.
Humans are however the one species that kills their own children. Some animals will kill new born that are sick or injured, some will abandon their new born but none set out to deliberately plan to kill their own children.
Don't even get me started on the Weasel males and what they do. Horrific, the very reason I call child molesters Weasels.
Okay - Birds.
Birds will kill their own species,
BUT the victim is usually mad, diseased, or both. It isn't done out of vengeance.
Several species of bird will kill other species eggs and leave theirs in the nest in exchange. But that's other species. Doesn't qualify.
Lions -
Lions will kill cubs less than two years old when they assume control of the pride. The short answer is that as long as there are cubs nursing, the mothers will not go into heat. A typical male lion has a lifespan of about 10 years, 5 of which to mate. The motive is biologically driven, not malicious. If it were, the lion would not stop at the nursing cubs.
Weasels -
Weasels will take the opportunity to kill as many prey animals as they can find, and leave them scattered about instead of just killing what they need to survive. They will also kill off competitors in the mink family (minks, skunks, ferrets, etc.) , as well as rodents. However, they typically do not kill off other weasels, even though the males will fight fiercely during mating season, it isn't to the death. Though of course, some animals may die from their injuries later on. Death is a consequence, it isn't the intention.
Many animals will kill or abandon their young if they are somehow 'wrong'. It's biology, not intent.
