Open biomimetic 3D-printable surrogate eggs for avian incubation research and conservation breeding

Abstract Artificial surrogate eggs are widely used in avian incubation research, behavioral ecology and conservation breeding, but existing models are often handmade, species-specific and difficult to reproduce across studies or institutions. This limits their use for comparative incubation research, standardized monitoring and evidence-based conservation breeding. We present an open-access dataset of biomimetic, 3D-printable surrogate egg models designed to approximate the geometry, mass and incubation-relevant thermal properties of natural avian eggs, allowing standardized egg substitution and datalogger deployment. The dataset contains 409 surrogate egg models for 129 focal bird species selected to span egg size and shape diversity. A surrogate-species selection table extends their potential use to approximately 98% of species in the representative Stoddard comparative avian egg-shape reference dataset, which comprises approximately 1,400 species, representing about 14% of recognized global avian diversity. Candidate surrogates are identified by matching egg length, asymmetry and ellipticity within tolerance limits based on typical intraspecific variation. Model-specific guidance helps users adjust printed eggs to biologically realistic target masses. Each focal species has up to four size-dependent model variants: (1) a solid husbandry model for egg substitution and visual mimicry, available for all species; (2) a fillable shell model designed to approximate natural egg mass and thermal capacity; (3) a single-datalogger research model with a central internal cavity, removable closure and insertion port; and (4) a three-datalogger model with lateral cavities for measuring within-egg thermal gradients. Availability of fillable and datalogger variants depends on egg size. Accompanying thermal-validation data document laboratory heating and cooling trials with domestic chicken and Japanese quail eggs. Ready-to-print STL files are supplied with species metadata, fabrication guidance, filling protocols, post-processing recommendations, a surrogate-species selection table, a mass-distribution table and thermal-validation documentation. The resource is archived in Zenodo under a Creative Commons Attribution 4.0 International license. By linking biomimetic design, open 3D-printable models and cross-species surrogate selection, it enables local fabrication and adaptation of surrogate eggs for reproducible incubation research, comparative studies and conservation breeding.