They put you at the butt of every joke with their laughter-like call and have an unwelcome tendency to snatch sausages from buns – but there’s a lot more to the cheeky kookaburra. Did you know these birds also form complex families that include chores, slacking off from chores, stepparents and divorce! Maybe you can relate…
A typical laughing kookaburra family (Dacelo novaeguineae) actually includes a breeding pair (Mum and Dad) plus up to eight of their offspring who’ve stayed on to help raise their future brothers and sisters.
These helpers are supposed to fulfill chores… like defending their territory and finding food for the young. But guess what? Sons and daughters aren’t equally handy at helping out…
Sons vs. Daughters
In fact while sons work tirelessly, the daughters are so rubbish at helping they decrease the new chicks’ chance at survival! Probably too busy getting their beak pierced and texting boys. But whatever the reason, it does mean couples with only daughters helping have the lowest success rate when raising chicks. Lower even than those parents who have no helpers at all.
In addition to slacking off, daughters fly the coop sooner than their brothers too. At age one, when both sexes are sexually mature, 79% of sons are still helping whilst just 57% of daughters are. Some daughters even leave before they’ve helped at all.
What’s a little odd though, is that kookaburra pairs with no helpers are more likely to have daughters – despite them being the least helpful of the sexes.
So… why? Why not have sons instead who’re more helpful? Well, scientists believe it’s because unassisted pairs usually exist in smaller territories where there’s not as much food. Therefore daughters are better because they leave the nest sooner, letting Mum and Dad say goodbye to those freeloaders sooner too.
What’s also odd, is that despite a strictly exclusive (or monogamous) relationship between the breeding pair of kookaburras, studies have found that an unhappy female will ‘initiate a divorce’. Female kookaburras don’t want much – just for the male to do all of the parental care. If he doesn’t cut the mustard she can move on, leaving dear old Dad alone with their offspring.
On a slightly more positive note, any offspring helping don’t follow Mum’s lead. Instead, they stay with their father continuing to help with the chores. Should he find a new partner, a would-be stepmother to the helpers, they stay on to help raise their stepsiblings too. Now that’s family!
Legge, S. (2000). The effect of helpers on reproductive success in the laughing kookaburra. Journal of Animal Ecology, 69(4), 714-724.
Legge, S., & Cockburn, A. (2000). Social and mating system of cooperatively breeding laughing kookaburras (Dacelo novaeguineae). Behavioral Ecology and Sociobiology, 47(4), 220-229.
Legge, S., Heinsohn, R., Double, M. C., Griffiths, R., & Cockburn, A. (2001). Complex sex allocation in the laughing kookaburra. Behavioral Ecology, 12(5), 524-533.