Like humans, some bird species mate for life and rear chicks together. But do they squabble like we do when one partner seems to be slacking off? The answer seems to be yes.
A forthcoming article in the Biological Journal of the Linnean Society describes research on vocalizations between Zebra Finch mates (Taeniopygia guttata) when they're incubating eggs. Zebra Finch couples share all chick-rearing responsibilities, including sitting on the nest before the chicks hatch. They sit in shifts about a half-hour long; while one sits, the other goes in search of food. When it's time to change shifts, the finches have what sounds like a conversation. Researchers were curious about whether this finch-to-finch conversation would change if one spouse were late returning to the nest for his or her turn.
Working with twelve pairs of Zebra Finches incubating eggs in a large aviary, researchers trapped the male of each pair at the beginning of a foraging shift and detained him for an entire hour. Remember, his spouse was home on the nest, expecting him to return in a half hour. She did not leave the nest while waiting. Instead, she and the male had a, um, rapid conversation when he finally returned, vocalizing at each other faster than usual. (We imagine a heated argument.)
Are you wondering whether a female took extra time away from the nest if her spouse came back late? The answer: only if the male didn't talk with her much. If the late-arriving male initiated only a short conversation, the female would fly off for up to an hour. However, if the male took the time to "talk" longer with the female, she'd come back in 30 minutes. In other words, it looked as if the female got back at the male only if both spouses did not talk long enough to sort things out.
No word on what the unhatched chicks thought about these delayed arrivals and arguments. Perhaps a next-generation study is in order.