Ecologists are increasingly turning to historical abundance data to understand past changes in animal abundance and more broadly the ecosystems in which animals occur. However, developing reliable ecological or management interpretations from temporal abundance data can be difficult because most population counts are subject to measurement or estimation error. There is now widespread recognition that counts of animal populations are often subject to detection bias. This recognition has led to the development of a general framework for abundance estimation that explicitly accounts for detection bias and its uncertainty, new methods for estimating detection bias, and calls for ecologists to estimate and account for bias and uncertainty when estimating animal abundance. While these methodological developments are now being increasingly accepted and used, there is a wealth of historical population count data in the literature that were collected before these developments. These historical abundance data may, in their original published form, have inherent unrecognised and therefore unaccounted biases and uncertainties that could confound reliable interpretation. Developing approaches to improve interpretation of historical data may therefore allow a more reliable assessment of extremely valuable long-term abundance data. This dataset contains details of over 200 historical estimates of Adelie penguin breeding populations across the Australian Antarctic Territory (AAT) that have been published in the scientific literature. The details include attributes of the population count (date and year of count, count value, count object, count precision) and the published estimate of the breeding population derived from those attributes, expressed as the number of breeding pairs. In addition, the dataset contains revised population estimates that have been re-constructed using new estimation methods to account for detection bias as described in the associated publication. All population data used in this study were sourced from existing publications.

We estimate population size in terms of the number of occupied nests for the Adélie penguin metapopulation in western Mac. Robertson Land, East Antarctica in 2009/10 and 2019/20. We also assessed demographic data from a single breeding site in the central part of this area (Béchervaise Island: 67°35'S, 62°49'E) including reproductive success, resight data, and fledgling mass from 1991/92 to 2019/20. We collated environmental covariates of potential drivers in this area over the same time period from sources described below. These are presented in the file “Time series demography and environmental covariates.xls”. Environmental covariates: Sea-ice concentration: Summer sea-ice concentration (SIC) was obtained for the area bounded by longitudes 60 - 65°E, to the south by the Antarctic coastline and the north by latitude 66.75°S. This approximately 250 km stretch of coastline incorporates the location of all Adélie penguin breeding sites across the metapopulation. The area defines the most northerly limit of fast-ice during chick rearing and encompasses the longitudinal range of the birds’ summer foraging activities. The sea-ice contained within this ‘near-shore’ region is predominantly composed of fast-ice (ice that is attached to land but covers seawater). Summer SIC was calculated as an average over the three-week period 25th December to 15th January when adults are guarding chicks for each breeding season. Winter SIC was determined in the following three areas of the penguins’ winter migratory route as defined previously. Each area was defined between specific longitudes and from 50°S south to the Antarctic coastline. The sea-ice contained within this area is composed of fast-ice near the coastline and pack-ice (all sea-ice that is not fast-ice) beyond the fast-ice edge. Two sectors defined the outward journey as they travelled westward towards their winter foraging grounds (50 - 65°E during March, and 30 - 50°E during April), a winter area (15 - 30°E during May-Jul) was considered as the sea ice became more extensive with both 15-100% SIC and 15-80% SIC which is considered more in line with suitable winter foraging ice conditions. The final area was associated with their eastwards journey towards the colony (30 - 50°E during Aug-Sep). For each area and time period, an average SIC was determined for each year in each of these areas. SIC values reflect the total area (km2) covered in sea-ice between either 15-100% or 15-80% SIC in each year and time period using 25x25km pixels. Sea-ice data were obtained from the National Snow and Ice Data Center (NSIDC) (Cavalieri et al. 1996) using Raadtools (Sumner 2017). Broad-scale climatic indices and local weather conditions: We determined the weather conditions during periods reflecting the end of the austral summer when the penguins were leaving their colonies (Feb-Mar) and the inter-breeding winter period (Apr-Sep). The Southern Oscillation Index (SOI) and the Southern Annular Mode (SAM) were included as broad indicators of climatic conditions, and local weather conditions included air and windchill temperatures. SOI was obtained from the Australian Bureau of Meteorology (www.bom.gov.au) and SAM from the NOAA Climate Prediction Centre (http://www.cpc.noaa.gov/products/precip/CWlink/daily_ao_index/aao/aao_index.html). Mawson Station local weather: Local weather data recorded at Mawson Station were obtained from the Australian Bureau of Meteorology. We considered two covariates: windchill and air temperatures both reported in °C. Windchill temperatures were determined from the ambient air temperature, wind speed and the relative humidity: AT= Ta +0.33e-0.7ws-4.0, where Ta is the dry bulb temperature (°C), e is the water vapour pressure (hPa), and ws is the windspeed (ms-1) at 10 m elevation. Water vapour pressure was determined from: (see the actual equation in the download file - "Emmerson_AADC Metadata Records_GCB_2022.docx" - unable to be reproduced here), where rh is the relative

This indicator is no longer maintained, and is considered OBSOLETE. INDICATOR DEFINITION Breeding populations of Adelie penguins at Davis, Mawson and Casey (including Shirley Island and Whitney Point). TYPE OF INDICATOR There are three types of indicators used in this report: 1. Describes the CONDITION of important elements of a system; 2. Show the extent of the major PRESSURES exerted on a system; 3. Determine RESPONSES to either condition or changes in the condition of a system. This indicator is one of: CONDITION RATIONALE FOR INDICATOR SELECTION The breeding population of Adelie penguins is related to resource availability (nesting space and food), behavioural mechanisms (immigration/emigration and breeding effort/success) in addition to climate change and human impacts (fisheries, tourism, pollution, disturbance). Monitoring these colonies and interpretation of the data provides information on changes in the Antarctic ecosystem. DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAM Spatial scale: Colonies near Australian Stations - Casey (lat 66 deg 16' 54.5" S, long 110 deg 31' 39.4" E) Davis (lat 68 deg 34' 35.8" S, long 77 deg 58' 02.6" E) Mawson (lat 67 deg 36' 09.7" S, long 62 deg 52' 25.7" E) All colonies on - Shirley Island (lat 66 deg 16' 55.9" S, long 110 deg 29' 17.9" E) and Whitney Point (lat 66 deg 15' 08.6" S, long 110 deg 31' 40.1" E) Frequency: Annual surveys at Shirley Island and Whitney Point. Other colonies every 2-3 years, depending on logistical constraints. Measurement technique: Each colony is visited and all breeding birds are counted from the ground by two or three personnel performing replicate counts. Supplementary census data are obtained from oblique ground and aerial photographs. All breeding adults in a colony are counted. Considerations regarding disturbance associated with census visits are also incorporated into monitoring strategies. The lack of annual census data for some colonies does not reduce the value of these long-term monitoring programmes. RESEARCH ISSUES Adelie Penguin populations throughout East Antarctica have shown sustained, long-term increases for the past 30 or more years; in contrast, populations elsewhere around the Antarctic and on the Antarctic Peninsula have exhibited decreases or no clear long-term trends (Woehler et al. 2001). Greater coverage of colonies throughout the AAT would provide a more accurate estimate of the total annual breeding population in East Antarctica. In addition to basic inventory requirements, data on the population trends would contribute to a better understanding of the role of Adelie penguins in the Antarctic ecosystem, and provide managers with feedback or management strategies. LINKS TO OTHER INDICATORS

This dataset contains data on the habitats, distribution and numbers of Adelie Penguins (Pygoscellis adeliae) in the Mawson area, Antarctica during 1981 and 1988. The data are obtained from aerial photographs obtained at various times, during the 1981-82 and 1988-89 seasons. The results are listed in the documentation. Comparisons are made with census data collected in the 1971-72 summer. Data from this record has been incorporated into a larger Adelie penguin dataset described by the metadata record - Annual population counts at selected Adelie Penguin colonies within the AAT (SOE_seabird_candidate_sp_AP). It also falls under ASAC project 1219 (ASAC_1219).

The current distribution of Adelie penguin breeding colonies in the AAT is being mapped through a series of 'occupancy' surveys. A GIS of potential Adelie penguin breeding habitat was developed to structure the overall search effort. Information about the GIS is given in Southwell et al. (2009) and in the related metadata record 'Sites of potential habitat for breeding Adelie penguins in East Antarctica' with Entry ID AAS_4088_Adelie_Potential_Habitats. The AAT coastline was broken into groups and subgroups which were surveyed when logistics allowed. All sites of potential habitat in each section were searched and a record of whether breeding penguins were present or absent was made. Most surveys were undertaken during the Adelie penguin breeding season when breeding penguins would have been present; any surveys outside the breeding season made observations of the presence or absence of guano. Most surveys have been undertaken from aircraft (both helicopters and fixed wing), but some have been done from the ground. Maps of potential breeding habitat in the groups and subgroups were produced from the GIS to use in the field surveys. The data recorded for each search campaign included the latitude and longitude of the centroid of each site that was searched, the data of search, the observer(s), and the state of occupancy (present or absent). These data were incorporated into the occupancy surveys undertaken as part of AAS project 4088. See the metadata record for that project to access the data (at the provided URL).

This dataset contains data on the habitats, distribution and numbers of Adelie Penguins (Pygoscellis adeliae) along the Vestfold Hills coast (including colonies on the mainland and offshore islands) during November 1973. The data are obtained from counts at the colonies and black and white photographs. Some aerial photographs were taken at Davis in 1981-82 and 1987-88, and will be compared to the results of this survey. The results are listed in the documentation. A total of 174178 26127 breeding pairs were counted. An increase in Adelie penguin population was found at most locations in East Antarctica. Data from this record has been incorporated into a larger Adelie penguin dataset described by the metadata record - Annual population counts at selected Adelie Penguin colonies within the AAT (SOE_seabird_candidate_sp_AP). It also falls under ASAC project 1219 (ASAC_1219).

This indicator is no longer maintained, and is considered OBSOLETE. INDICATOR DEFINITION Demographic parameters for the Adelie penguin at Bechervaise Island near Mawson. TYPE OF INDICATOR There are three types of indicators used in this report: 1.Describes the CONDITION of important elements of a system; 2.Show the extent of the major PRESSURES exerted on a system; 3.Determine RESPONSES to either condition or changes in the condition of a system. This indicator is one of: CONDITION RATIONALE FOR INDICATOR SELECTION The Adelie penguin is a relatively long lived sea bird dependent on krill. It is expected that major changes in the availability of food (krill) to sea birds will be reflected ultimately in recruitment into the breeding population. Causes of changes in the availability of krill relate directly to changes in both the biological and physical environment brought about by man made or natural means. Ageing populations may give an outward appearance of stability in terms of numbers at a breeding colony but such a condition may mask a decline in recruitment. To determine whether there are environmental influences on the population it is necessary to undertake detailed demographic studies. Demographic studies carried out over many years on animal populations comprising known age cohorts are required to determine those factors responsible for any observed changes in recruitment and/or mortality. Population reconstruction techniques provide estimates of recruitment and mortality and relate these functions to population size and/or population trends. These studies may alert us to possible changes in the ecosystem particularly related to the availability of food to the penguins or changes to the physical environment. The identification of the cause of changes must come from detailed investigations of food availability and the environment carried out at the same time. Annual breeding success at Bechervaise Island (eggs laid to chicks fledged) varies enormously from 0 in catastrophic years to above 1 for good seasons. The population at Bechervaise Island near Mawson has been monitored since 1990 as part of the CCAMLR Ecosystem Monitoring Program. Chicks and adults have been tagged annually. The number of breeding pairs has increased slightly between 1990-2001, but changes in the non -breeding population are unknown. Demographic studies based on the return rate of birds tagged as chicks provide information on trends in the overall population and the net rate of recruitment. Since it is intended that this program be undertaken indefinitely it makes this population an excellent subject for monitoring in the context of the SOE. DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAM Spatial Scale: Restricted to the Mawson region. Similar studies are carried out by other national research programs at Terra Nova Bay (Italy) and on the Antarctic Peninsula (USA). Frequency: Annual Measurement Technique: The Adelie penguin population at Bechervaise Island consists of approximately 1800 breeding pairs. Each breeding season since 1990/91 in excess of 250 chicks have been given implanted electronic identification tags. The return of birds to their natal colony has been detected automatically by the Automated Penguin Monitoring System (APMS)or by checking all birds with a hand held tag reader. Additional and associated biological data as prescribed by CCAMLR (1997 are collected to aid interpretation of demographic and other trends. To detect trends in the population size and in demographic parameters, particularly of recruitment, it will be necessary to maintain an annual tagging program of chicks and recording of all tagged birds. RESEARCH ISSUES comprehensive analysis of the data collected over the duration of this study is required to determine natural variation and potential anthropogenic influences affecting Adelie penguin population dynamics. LINKS TO OTHER INDICATORS Sea-ice extent and concentration.

An occupancy survey in December 2009-February 2010 and January 2011 found a total of 6 islands along the Knox coast had populations of breeding Adelie penguins. The survey in 2009/10 was conducted from a fixed wing aircraft and oblique aerial photographs were taken of occupied sites. The aerial photographs were geo-referenced to satellite images or the coastline shapefile from the Landsat Image Mosaic of Antarctica (LIMA, tile E157) and the boundaries of penguin colonies were digitised from the geo-referenced photos. Details for each island are: Merrit: Photographs taken on 1 February 2010 and geo-referenced to LIMA tile E157 Cape Nutt: Photographs taken on 5 January 2010 and geo-referenced to a Quickbird satellite image taken on 17 February 2011 Ivanoff Head: Photographs taken on 27 December 2009 and geo-referenced to LIMA tile E157 Please refer to the Seabird Conservation Team Data Sharing Policy for use, acknowledgement and availability of data prior to downloading data.

This dataset comprises oblique aerial photographs of multiple Adelie penguin breeding sites in East Antarctica. The photographs were taken using hand-held digital cameras from fixed-wing aircraft and helicopters used by the Australian Antarctic Program. The aircraft flew at or above the minimum wildlife approach altitude of 750 m with a horizontal offset distance from the site of approximately 500-600m. The date and exact location of the aircraft when each photo was taken is embedded in the EXIF data of each photo. All photographs that were taken are included despite varying image quality due to environmental conditions, camera type and altitude. Generally an attempt was made to photograph the entire breeding site (usually an island, occasionally an outcrop of continental rock) with a series of zoomed, overlapping photos. Sometimes this was not possible when the site was large, and in these cases the overlapping photos covered the locations where colonies were known to exist from previous survey work. In some cases a site was over-flown at an altitude of 1200m so that a single photo of the entire site could be taken. These photos are useful in piecing together the detailed photos. The database of potential Adelie penguin breeding habitat in Southwell et al. (2016a) was used to associate photos to a particular breeding site and structure how the photos are stored. The breeding site database has a unique identifying code of every site of potential breeding habitat in East Antarctica, and the sites are aggregated into sub-groups and then groups. The file structure in which the photos are stored has a combination of ‘group’ and ‘split-year breeding season’ at the top level (eg VES 2015-16 contains all photos in group VES (Vestfold Hills and islands) taken in the 2015-16 breeding season). Within each group-year folder are sub-folders for each breeding site where photos were taken (eg IS_72276 is Gardner Island in the VES group). If an overview photo was taken there are separate sub-folders for overview and detailed photos in the site sub-folder. These data also superseded an earlier dataset of 2009-2016 data - https://data.aad.gov.au/metadata/records/AAS_4088_Adelie_oblique_photos Please refer to the Seabird Conservation Team Data Sharing Policy for use, acknowledgement and availability of data prior to downloading data.

These data have been superseded by a more recent dataset, described here - https://data.aad.gov.au/metadata/records/AAS_4088_Oblique_Aerial_Photos This dataset comprises oblique aerial photographs of multiple Adelie penguin breeding sites in East Antarctica. The photographs were taken using hand-held digital cameras from fixed-wing aircraft and helicopters used by the Australian Antarctic Program. The aircraft flew at or above the minimum wildlife approach altitude of 750 m with a horizontal offset distance from the site of approximately 500-600m. The date and exact location of the aircraft when each photo was taken is embedded in the EXIF data of each photo. All photographs that were taken are included despite varying image quality due to environmental conditions, camera type and altitude. Generally an attempt was made to photograph the entire breeding site (usually an island, occasionally an outcrop of continental rock) with a series of zoomed, overlapping photos. Sometimes this was not possible when the site was large, and in these cases the overlapping photos covered the locations where colonies were known to exist from previous survey work. In some cases a site was over-flown at an altitude of 1200m so that a single photo of the entire site could be taken. These photos are useful in piecing together the detailed photos. The database of potential Adelie penguin breeding habitat in Southwell et al. (2016a) was used to associate photos to a particular breeding site and structure how the photos are stored. The breeding site database has a unique identifying code of every site of potential breeding habitat in East Antarctica, and the sites are aggregated into sub-groups and then groups. The file structure in which the photos are stored has a combination of 'group' and 'split-year breeding season' at the top level (eg VES 2015-16 contains all photos in group VES (Vestfold Hills and islands) taken in the 2015-16 breeding season). Within each group-year folder are sub-folders for each breeding site where photos were taken (eg IS_72276 is Gardner Island in the VES group). If an overview photo was taken there are separate sub-folders for overview and detailed photos in the site sub-folder. Please refer to the Seabird Conservation Team Data Sharing Policy for use, acknowledgement and availability of data prior to downloading data.