Help at the nest sets chicks up for life

A chick's chances throughout life will depend on a good environment and good parenting in its earliest months. One of the ways that chicks can get ahead is to have an extra relative looking after them. New research shows that the benefits of having a 'helper at the nest' extend even into adulthood. 'It is a paradox that individuals help to rear others instead of breeding on their own,' explains Dr Lyanne Brouwer of the Australian National University. 'But classic theory explains this by 'kin-selection'; by helping to raise relatives, helpers indirectly pass on a part of their own genes. The benefits that an individual gains can be calculated in terms of the number of genes that they pass on to the next generation.' Calculations like this can help us understand why some species of bird help out at relatives' nests whilst other species do not. In their article in PLoS One, Brouwer and her colleagues argue that the long-term benefits to bird survival from having a friendly relative on hand need to be borne in mind when making these calculations. The scientists studied the Seychelles warbler, found only in a few islands in the Republic of Seychelles in the Indian Ocean. This is one of the nine per cent of bird species that are classed as cooperative breeders. Their limited habitat, bounded on every side by the sea, often forces related birds to share the territory they grew up in. 'Once all the habitat on the island is occupied, new young have nowhere to go to, so they stay with their parents and often help to rear the next brood,' says Brouwer. 'The Seychelles warbler is a typical example of a cooperative breeder.'