Abstract:
This dataset contains ringing data of snowy sheathbills (Chionis albus) captured, ringed and released on Bird Island, South Georgia from September 2024 to September 2025, as well as subsequent resightings of birds throughout the year. Ringing data includes summary morphometrics including size and weight measurements. Resightings were made on an ad-hoc basis but represent high effort throughout the year.
Data were collected as part of an initial study of sheathbills at Bird Island, aiming to discern population structure, comparative morphometrics with Antarctic birds, and for sexing via discriminant functions. Data were collected by Bird Island Zoological Field Assistants.
Funded as part of the BAS Bird Island Long-term Monitoring Programme.
Keywords:
Bird Island, Chionis albus, South Georgia, bird ecology, morphometrics, population dynamics, ringing data, snowy sheathbill
Day, G., Callaghan, J., Rayner, C., Tarrant, P., & Bennison, A. (2025). Ringing data and resightings of snowy sheathbills (Chionis albus) from Bird Island, South Georgia, September 2024 to September 2025 (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/231b4167-5910-4107-83de-72d6a20d159d
| Access Constraints: | None. |
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| Use Constraints: | This data is governed by the NERC data policy http://www.nerc.ac.uk/research/sites/data/policy/ and supplied under Open Government Licence v.3 http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/. |
| Creation Date: | 2025-10-27 |
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| Dataset Progress: | Complete |
| Dataset Language: | English |
| ISO Topic Categories: |
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| Parameters: |
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| Personnel: | |
| Name | UK PDC |
| Role(s) | Metadata Author |
| Organisation | British Antarctic Survey |
| Name | Dr George Day |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Name | Jessica Callaghan |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Name | Charlotte Rayner |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Name | Peter Tarrant |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Name | Dr Ashley Bennison |
| Role(s) | Investigator, Technical Contact |
| Organisation | British Antarctic Survey |
| Parent Dataset: | N/A |
| Quality: | Field_sex and field_age were determined by field observations and so may be inaccurate. Where morphometric data are missing, this is due to the bird having been released immediately after ringing to avoid stress. |
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| Lineage/Methodology: | From September 2024 to September 2025, sheathbills were caught and ringed at Bird Island Research Station, South Georgia (54°00'S; 38°03'W). Catching was primarily carried out at Freshwater Beach, Bird Island, where the Research Station is located. However, birds were also caught across several beaches on the south of the island. Methods for catching largely consisted of the use of a hand-net and head/leg noosing. Once caught, birds were ringed with a metal F (inside diameter: 9mm) or G (inside diameter: 11mm) British Trust for Ornithology (BTO) ring, with Fs being applied to all birds with a tarsus diameter < 8mm. Birds caught as adults were ringed with the metal ring on the right tarsus and known-age chicks on the left tarsus. Birds were also colour banded on the opposite leg using a blue or yellow darvic ring, depending on the location. Zones for darvic colour allocation were determined based on proximity to the Research Station - with blue rings used at the base and along the south and south-western coast of the island, and yellow elsewhere. The first three birds ringed did not receive a darvic as they were part of a pilot study investigating which size of BTO ring would fit. Once ringed, measurements were taken including: wing length (flattened chord), culmen length (from the tip of the upper mandible to the edge of the feathering at the base of the skull), culmen depth (the maximum depth between the bill without sheath and under the edge of the lower mandible), culmen width (the maximum width of the mandible without the sheath), sheath length (from the edge of the sheath to the edge of the feathering at the base of the skull), sheath depth (the maximum depth between the upper edge of the sheath and under the edge of the lower mandible), tarsus length (the minimum tarsus length), tarsus depth (the maximum depth of the from the anterior to the posterior of the leg) and mass. Field age was recorded using EURING age codes. The EURING age coding system was designed in the northern hemisphere based on the calendar year January to December. For use in the southern hemisphere, where the breeding season occurs at the opposite end of year, it must be adapted. As such, years are considered to begin in June rather than January. Where birds were found to be in moult, moult scores were determined following Bensch and Grahn's standardised methodology (Bensch and Grahn 1993). Primary feathers are assigned a score between 0 and 5 based on their age, which together indicates which stage of moult the bird is in. Resightings were almost all made from locations across Bird Island, with the exception of one resighting from King Edward Point, South Georgia, and one from onboard from the Fishery Patrol Vessel Pharos. |
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| Temporal Coverage: | |
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| Start Date | 2024-09-01 |
| End Date | 2025-09-05 |
| Spatial Coverage: | |
| Latitude | |
| Southernmost | -54.28363 |
| Northernmost | -54.00336 |
| Longitude | |
| Westernmost | -38.07497 |
| Easternmost | -36.49498 |
| Altitude | |
| Min Altitude | N/A |
| Max Altitude | N/A |
| Depth | |
| Min Depth | N/A |
| Max Depth | N/A |
| Location: | |
| Location | South Georgia Island |
| Detailed Location | King Edward Point |
| Location | South Georgia Island |
| Detailed Location | Bird Island |
| Distribution: | |
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| Distribution Media | Online Internet (HTTP) |
| Distribution Size | 72KB |
| Distribution Format | N/A |
| Fees | N/A |
| Data Storage: | 3 x .csv files: sheathbill_ringing_bird_island_2024-25.csv, sheathbill_resightings_south_georgia_2024-25.csv, and location_codes.csv. The first contains the ringing data with associated morphometrics, the second a list of resightings, and the third a list decoding the location codes used in the first two tables. sheathbill_ringing_bird_island_2024-25.csv contains the following columns: species - BTO five letter species code for snowy sheathbill date_ringed - date bird caught and ringed location - location code for place caught bto_ring_id - metal ring alphanumeric code darvic_ring_id - coloured darvic ring alphanumeric code field_sex - sex as determined by field observations field_age - EURING age code as determined by field observations wing_length_mm - wing length (in mm) culmen_length_mm - culmen length (in mm) culmen_depth_mm - culmen depth (in mm) culmen_width_mm - culmen width (in mm) sheath_depth_mm- sheath depth (in mm) sheath_length_mm - sheath length (in mm) tarsus_length_mm - tarsus length (in mm) tarsus_diameter_mm - tarsus diameter (in mm) mass_g - mass (in grams) The following columns contain moult scores determined following Bensch and Grahn's standardised methodology: m_0 - number of primary feathers scored as 0 m_1 - number of primary feathers scored as 1 m_2 - number of primary feathers scored as 2 m_3 - number of primary feathers scored as 3 m_4 - number of primary feathers scored as 4 m_5 - number of primary feathers scored as 5 moult_score - a total score to define overall state of moult sheathbill_resightings_south_georgia_2024-25.csv contains the following columns: darvic_ring_id - alphanumeric code from darvic ring on resighted bird date_resighted - date bird resighted location_resighted - location code for where bird resighted date_ringed - date bird originally ringed season_ringed - season of the year (summer or winter) when bird originally ringed location_codes.csv contains the following columns: location_code - short alphabetic code description - full location name latitude_degree_north - latitude of location (in decimal degrees) longitude_degree_east - longitude of location (in decimal degrees) |