(1) Dataset Title Multi-temporal UAV orthomosaics of an Adélie penguin colony at Cape Hallett, Ross Sea, Antarctica (2018–2025) (2) Purpose of Data Acquisition To establish a spatially co-registered multi-year UAV orthomosaic time series for long-term ecological monitoring of the Adélie penguin (Pygoscelis adeliae) breeding colony at Cape Hallett, Antarctic Specially Protected Area No. 106 (ASPA No. 106), Ross Sea, Antarctica. Because no real-time kinematic (RTK) ground control network is available at the site, absolute positional offsets of several metres accumulate between survey years. The dataset was therefore designed to achieve relative spatial consistency across the time series by co-registering all annual orthomosaics to a common 2018 primary reference through an automated image-to-image registration workflow. (3) Brief Description Six austral-summer UAV campaigns (2018, 2021, 2022, 2023, 2024, 2025) acquired a total of 4,471 nadir RGB images over the Cape Hallett Adélie penguin colony (72°19'S, 170°13'E). The 2018 campaign, conducted with a DJI Matrice 600 hexacopter and a Canon EOS 5DS DSLR camera (GSD 0.72 cm/pix), serves as the primary reference orthomosaic. Orthomosaics from the five subsequent campaigns (2021–2025), acquired with DJI consumer-grade quadcopters (Mavic 2 Pro, 2 Enterprise Advanced, 3 Pro, 4 Pro), were co-registered to the 2018 primary using an automated pipeline combining deep learning-based (LightGlue + SuperPoint) and classical (SIFT, ORB) feature matching with four candidate geometric transformation models (translation, similarity, affine, second-order polynomial). Independent tie-point validation yielded median post-warp residuals of 2.02–2.38 m across all campaigns. (4) Deposit Contents The deposit contains: (1) the 2018 primary orthomosaic, (2) five pre-registration secondary orthomosaics, (3) 20 co-registered orthomosaics (5 years × 4 models), (4) Agisoft Metashape photogrammetric survey reports (PDF) for each campaign, (5) 47 surveyed rock markers as shapefile and CSV, (6) independent post-warp residual measurements (20 CSV files), (7) adopted co-registration model metadata (JSON) per secondary year, and (8) the custom Python co-registration pipeline that reproduces products (3), (6) and (7) from inputs (1) and (2) (Pipeline_CapeHallettUAVortho-coreg.7z, MIT licence). All spatial data are in WGS 84 / UTM zone 59S (EPSG:32759). (5) Keywords Adélie penguin, penguin colony monitoring, UAV, orthomosaic, remote sensing, Structure-from-Motion photogrammetry, image co-registration, multi-temporal time series, LightGlue, SuperPoint, Cape Hallett, Ross Sea, Antarctica, ASPA 106 (6) Spatial Extent 72°19'S, 170°13'E (Cape Hallett, northern Victoria Land, Ross Sea, Antarctica) Bounding box (EPSG:32759): Easting 472,940–474,305 m, Northing 1,974,587–1,975,656 m (7) Temporal Extent 2018-11-25, 2021-11-21, 2022-11-20, 2023-11-26, 2024-11-21, 2025-11-21 (8) Data Formats GeoTIFF (orthomosaics), PDF (photogrammetry reports), Shapefile (reference markers), CSV (residual statistics, marker coordinates), JSON (adopted model metadata), Python source code (co-registration pipeline) (9) Licence, Access and Citation Terms - LICENCE The data in this record are released under the Creative Commons Attribution 4.0 International licence (CC BY 4.0, https://creativecommons.org/licenses/by/4.0/). Users are free to copy, redistribute, adapt, transform and build upon the material for any purpose, including commercially, provided that appropriate credit is given as specified below. The co-registration pipeline supplied in the same record is released under the MIT licence and covers the code only. - ATTRIBUTION IS MANDATORY Attribution is a condition of the CC BY 4.0 licence, not a courtesy. Any publication, report, presentation, derived dataset or product that uses these data — in whole, in part, cropped, resampled, reprojected or otherwise modified — must cite both items listed under Citation below. Users who modify the data must also state that changes were made, and must not imply endorsement by the data providers. - ACCESS PROCEDURE (managed separately from the licence) The licence governs what a user may do with the data once obtained; it does not mean the files download without checks. The record and its metadata are openly available, but the data files are marked "Request required" and must be requested through this record page. Requests are reviewed in consultation with the Principal Investigator, and applicants should state their name, affiliation and intended use. All archives in this deposit are password-protected, and the password is issued only after a request has been approved. This managed-access procedure reflects the status of the site as Antarctic Specially Protected Area No. 106 under Annex V of the Protocol on Environmental Protection to the Antarctic Treaty, and the fact that the full-resolution orthomosaics resolve the positions of individual nests. - REQUESTED PRACTICE (a request, not a licence restriction) The following do not restrict any right granted by CC BY 4.0. They are asked of users as a matter of research ethics and Antarctic environmental protection. Users are asked not to employ these data to plan or support any activity that would disturb the breeding colony, and not to redistribute nest-level positional information in a form that would enable such disturbance; to observe the ASPA No. 106 management plan and the permit requirements of their national Antarctic programme for any fieldwork informed by these data; and to contact the Principal Investigator before undertaking work that overlaps with the ongoing monitoring programme. - DISCLAIMER The data are provided "as is". The co-registration achieves relative spatial consistency across years (median independent post-warp residuals 2.02–2.38 m), but the dataset carries no real-time kinematic ground control and is not suitable for absolute geodetic positioning. Users are responsible for judging fitness for their own purpose. - CONTACT Yongsik Jeong (yongsik@kopri.re.kr); Jinku Park (jinku_park@kopri.re.kr); Jeong-Hoon Kim (jhkim94@kopri.re.kr, Principal Investigator), Korea Polar Research Institute (KOPRI). - Citation If you use this dataset, please cite the dataset and the Data Descriptor: Jeong, Y., Park, J., Kim, J.-U., Kim, Y., Oh, Y., Kim, S.-Y. & Kim, J.-H. CapeHallettUAVortho: Multi-temporal UAV orthomosaics of an Adélie penguin colony at Cape Hallett, Ross Sea, Antarctica (2018–2025). Korea Polar Data Center. https://doi.org/10.22663/KOPRI-KPDC-00003118 (2026). The Data Descriptor citation (Scientific Data) will be added to this record upon publication.