If you thought that humans were the only ones to fight over the kids, favour one child over the other or even divorce each other and split the kids between them, well it’s time to change the way you think, for a new study on territorial songbirds has found that they too are not immune from the effects of a "divorce".
The study of avian parenthood by a team of researchers led by Tudor Draganoiu, was conducted in the small mountain village of La Valla sur Rochefort, France where they spent five summers studying black redstarts, Phoenicurus ochruros.
The researchers noticed that not only did couples among these birds sometimes "divorce" each other due to conflicts or when one would desert the offspring, but that when this happened, they would often move away to a different location with a favoured young.
Each parent bird, as a result, took up the care of feeding and caring for certain fledglings.
As a part of the study, the researchers also recorded begging calls from all of the offspring, and found that some avian parents paid more attention to the calls of a favoured fledgling.
Tudor Draganoiu said that brood division of the avian couple could be a common characteristic across the bird species.
"I suspect that brood division could be a common characteristic across bird species and not only for insectivorous insects (there are examples also among nocturnal raptors and waders), but parent-offspring interactions after the fledgling (stage) are difficult to observe for many species," Discovery News quoted him, as saying.
"Brood division could possibly result from a conflict between the two sexes over the parental investment: each parent should try and do less work and push the other parent to work harder, in order both to maximize current reproductive success and to save energy for future reproductive events," he added.
And, though male birds tend to care for a fewer number of chicks than female birds, neither size nor sex of the fledgling makes much of a difference to the avian parents when it comes to their favourite.
Such brood division were also found to occur in a number of other songbirds, including blackbirds, robins, bluethroats, dunnocks, prairie warblers, song sparrows, white-throated sparrows and even some aquatic species, such as the great crested grebe and the coot.
The study was recently published in the journal Animal Behaviour.