Where do shearwaters go? by Zuzana Zajková

Animal movement represents the continuous succession of locations of an individual over time. By changes in movement, animals react to both internal stimuli and the environment. State-of-the-art biologging technologies allow scientists to track animals at various spatial and temporal scales, including long-distance migratory species. In this art work, I highlight year-round movements of two closely related seabird species: the Cory’s and Scopoli’s shearwater. To create the visualization, I used data collected from birds tagged with light-level geolocators, tiny tracking devices that allow researchers to reveal daily geographic locations through light measurements and astronomical algorithms. Information collected through tracking can pinpoint important areas for seabirds as well as help to identify possible threats at sea. In this case, the pelagic way of life of these species clearly revels the continental margins. In October, when the breeding period is over, the shearwaters leave their breeding colonies in the Canary and the Balearic Islands (Spain) and migrate south. They winter in highly productive oceanic areas, where they stay until the onset of a new migratory journey in February to return to their colonies.

The visualization shows 100 animal movement trajectories, selected randomly from a bigger dataset included in the book “Migration and Spatial Ecology of the Spanish Populations of Scopoli's and Cory's shearwaters” (SEO/BirdLife, 2017), which I co-authored. I opted for a minimalistic design, and chose the open-source programming language R to create the visualization.