Habitat geometry rather than visual acuity limits the visibility of a ground-nesting bird's clutch to terrestrial predators ...

• Main Authors: Hancock, George, Grayhson, Lizzie, Burrell, Ryan, Cuthill, Innes, Hoodless, Andrew, Troscianko, Jolyon
• Format: Dataset
• Language: English
• Published: Dryad 2023
• Subjects: FOS Biological sciences; camouflage; 3D scanning; occlusion; ground-nesting birds; lapwing; Vanellus vanellus
• Online Access: https://dx.doi.org/10.5061/dryad.wm37pvmtb; https://datadryad.org/stash/dataset/doi:10.5061/dryad.wm37pvmtb

The nests of ground-nesting birds rely heavily on camouflage for their survival, and predation risk, often linked to ecological changes from human activity, is a major source of mortality. Numerous ground-nesting bird populations are in decline, so understanding the effects of camouflage on their nesting behaviour is of relevance to their conservation concern. Habitat three-dimensional (3D) geometry together with predator visual abilities, viewing distance, and viewing angle determine whether a nest is either visible, occluded or too far away to detect. While this link is intuitive, few studies have investigated how fine-scale geometry is likely to help defend nests from different predator guilds. We quantified nest visibility based on 3D occlusion, camouflage, and predator visual modelling in northern lapwing, Vanellus vanellus, on different land management regimes. Lapwings selected local backgrounds that had a higher 3D complexity at a spatial scale greater than their entire clutches compared to local ... : Data Collection Sites All images and 3D scans were collected from two separate locations monitored by the Game and Wildlife Conservation Trust (GWCT); the Avon Valley in Hampshire [50.93105,-1.78462] and Burpham in Sussex [50.87198, -0.51812]. Predation Data Nest predation status was determined using nest temperature loggers (iButtons) and weekly nest checks from the date of discovery to the point of failure or hatching following the methods of Hartman and Oring (Hartman & Oring, 2006). Predated eggshell fragments or disappearance of clutches/eggs prior to egg weight estimated hatch dates were encoded as predation events. Nest and Null Photography and Scanning From March to Mid-June of 2021 and 2022, we photographed 115 lapwing nests and 3D scanned 83. The nests were scanned with an ASUS Zenfone AR using the Matterport Scenes app from a height of 1.2m. Scans and photographs were taken from a height of 1.2 metres at a flat 90o (vertical) angle from the ground. For each nest, an additional nest-less photo ...