Scarlet Macaw parents ‘play favorites,’ purposefully neglect younger chicks

Researchers have discovered that scarlet macaws purposefully neglect feeding the youngest chicks in most broods, even when resources are plentiful. This results in only one or two chicks being able to fledge — the process in which parents teach their young to fly and survive on their own — even though broods may contain up to four chicks.

Source: ScienceDaily.com