The overarching aim of the NEURONESt project was to complete the first interdisciplinary synthesis of the cognitive, hormonal, and neurobiological mechanisms underlying nest building by birds. Using the zebra finch Taeniopygia guttata as a model species, we aimed at combining methodologies from different fields to test current and important hypotheses that have not been empirically tested yet and that could shed light on some of the mechanisms underlying this behaviour, key for avian reproduction but almost entirely overlooked.
To date, whether innovation/problem-solving abilities are supported by ‘high’ cognitive capacities or rather can be best explained by a combination of reduced neophobia, perseverance and wider motor diversity is still the subject of an intense debate. In Objective 1, we specifically aimed at investigating whether birds could diversify their motoric repertoire through the building of a nest, a behaviour well known to involve a wide variety of motoric actions, and whether this could (i) influence their problem-solving abilities and (ii) relate to specific pattern of activation of the cerebellum. Altogether, these data are important because they could shed light on the mechanisms supporting innovation in birds and other species, including ours.
As nest building by birds occurs between the courtship and egg-laying periods, when androgens and oestrogens are still likely to be high in the circulation, it had been suggested that these sex steroid hormones might support building. Evidence to verify this causal relationship is still scant. In Objective 2, we aimed to identify the role(s) played by sex steroids during nest building, in a species in which the male is the primary builder, as well as to identify the mechanisms of sex-steroid action in the brain. Such work is timelier than ever because birds are constantly exposed to the environmental changes of the Anthropocene. These include a growing quantity of chemical pollutants that potentially act as endocrine disruptors. By providing a better understanding of the (neuro)endocrine mechanisms that underpin avian breeding, and specifically nest building, the results generated by Objectives 2A&B might help to predict how environmental pollutants might disrupt a behaviour fundamental to species survival.
While results from the work addressed in Objective 1 are still being analysed, our data show that circulating androgens in males are needed to support this important behaviour throughout the nest-construction period data (Objective 2), and thus the importance of sex steroids in the support of male nest building. We are now investigating the associated mechanisms of action in the brain of these steroids in relation to nest building.
