Spatial and structural characteristics of occupied nests of Calonectris borealis (Cory, 1881) in the Central Azores in 2025

The Azores Archipelago hosts approximately 75% of the global breeding population of Cory’s shearwater ( Calonectris borealis ). This species faces threats ranging from habitat degradation and invasive predators to climate change, which increase the vulnerability of its breeding sites. Effective conservation and threat assessment require data on breeding habitats, yet such information remains scarce. To address this gap, we aimed to provide a standardised baseline of the spatial and structural characteristics of active nests in the Azores Region. We present a comprehensive dataset based on a field survey conducted in 2025 across 11 colonies on four islands of the Azorean Central Group (Faial, Graciosa, Pico and Terceira). The dataset characterises 421 occupied nests and includes 5,812 individual records describing nest architecture (e.g. depth, width and substrate) and local topography (e.g. slope, orientation and proximity to the coast and infrastructure). Additionally, it contains 1,380 botanical records from vegetation surveys, identifying 106 vascular plant species. All data are standardised according to Darwin Core (DwC) requirements and are publicly available through the Global Biodiversity Information Facility (GBIF). This data package provides a resource for future spatial modelling and the development of targeted conservation strategies for seabirds.