Video: Birds observed arguing over parental duties for first time

Even bird spouses argue. A new study finds that zebra finches (Taeniopygia guttata) squawk it out if one partner is not fulfilling its parental duties. The species forms life-long pairs, where both males and females share childcare responsibilities every step of the way, from nest building to watching over eggs and chicks. When it comes to incubating their eggs, they are very strict on their shifts. Both males and females spend equal amount of time sitting on their eggs, and while one is sitting on their eggs the other goes foraging. To find out whether these birds actually engaged in vocal exchanges to “discuss” their parental duties, researchers monitored the behavior of 12 male-female pairs breeding in a large aviary. For each pair, they trapped the male while he was foraging, delaying his arrival back at the nest by 1 hour, instead of the usual 30 minutes. The video above shows what happens when the male returns on time; the partners engage in a normal vocal exchange. But when the male returns late, the pair has an accelerated vocal exchange, with both male and female alternating their calls more rapidly than usual, the team reports this month in Biological Journal of the Linnean Society. The researchers also found that the time the female spent away from the nest did not depend so much on how late her mate was in the previous shift, but rather on how much time he spent vocalizing when he came back. If the late-arriving male called only a few times (< 40 calls) then the female went off for anything between 20 to 60 minutes, depending on how late the male was. But if the delayed male called extensively (> 40 calls) the female was back from her foraging break in under 30 minutes. This shows that the birds don't just use a tit-for-tat strategy, but instead they talk about it, the authors say, and when the male has a good excuse for its tardiness the female responds by getting back from her foraging shift on time.