The birds are named for their black and white markings
The youngest members of zebra finch broods "explore more" than older siblings in adult life, say scientists.
Researchers investigated how the birds' behaviour was affected by the way their parents cared for them as hatchlings.
The team studied broods where females lay and incubate a clutch of eggs over a period of days, resulting in a size hierarchy within the clutch.
They found the youngest birds were more likely to explore their environment as adults in search of food.
The study, published in Animal Behaviour, tested over 100 captive zebra finches' exploratory behaviour to see whether hatching order, and consequently parental investment, affected their behaviour in adulthood.
Late hatched birds are smaller than their older siblings, and it is the larger hatchlings that "get the lion's share" when parents bring in food "because they can reach up higher and beg better," explained research team member Dr Ian Hartley from Lancaster University.