Understanding the resilience of wild birds to climate change: seasonal genomics of the annual migratory breeding cycle

Two closely related subspecies of white-crowned sparrow in North America, the Gambel’s (GWCS) and the Nuttall’s (NWCS), represent very recent and rapid subspecies divergence. This presents an excellent opportunity to study the recent evolution of seasonal behaviour by comparing the long-distance migrant, GWCS, with the year-long resident of California, NWCS. The white-crowned sparrow had a common ancestor with the Rufous-collared sparrow (RCS) during the Pleistocene era. RCS resides in the very distinct environment of South America and provides a powerful model for understanding the evolutionary adaptation of the seasonal behaviour of these wild-birds to historic and recent climate change. One population of Z. capensis has become non-seasonal allowing further "natural experimental" comparisons of gene networks involved in seasonality and vulnerable, or robust, they will be in the face of climate change. We propose to examine which genes show expression changes in a variety of tissues that are known as important regulators and targets of seasonal hormones. We know there are strong sex differences in gene expression and hormone levels, so we will use both males and females from each sub-species. We will compare NWCS with GWCS during different stages and behaviours during the year (during winter, arrival in Arctic, egg-laying, and pre-basic moult). For the selected genes, that we identify as critical, will use antibody staining to create 3D images for their protein localisation in the hypothalamus and pituitary. We will also follow up the significant genes, tissues and stages in the ancestral RCS to determine the evolutionary history of these regulators of annual behaviour. High-quality annotated genomes will be developed for these three species to understand their genetic differences and in order for accurate analysis of gene expression to be undertaken. This will also allow other researchers to conduct similar genome-wide studies in these species and empower further international research into the impact of climate on our wild-birds. We will thus be able to better understand seasonal periodicity and the recent evolutionary history of the sex-specific molecular processes that enable our wild birds to adapt their behaviour to a changing climate. Understanding these key processes and evolutionary history will help us better understand and predict the impact of the current climate emergency on our wild birds. Results from this study will be of consequence not just to science but will help inform at the very heart of the policy changes that will need to be made in our rapidly changing society. Understanding the ability of wild birds to adapt the basic biology of species (via changes in gene expression, behaviour, reproductive potential, environmental adaptability etc.) to a changing climate will allow us to better understand the impact of global environmental change and begin to develop strategies to mitigate these potentially devastating effects that will have consequences for all life on earth.