<p>The Arctic Falcon Specialist Group (AFSG) is an informal network of biologists with a research focus on Arctic-breeding peregrine falcons (<em>Falco peregrinus</em>) and gyrfalcons (<em>Falco rusticolus)</em>. AFSG was established to enhance the coordination and collaboration on the monitoring of the two Arctic falcon species and the initial joint effort was to compile the first overview of Arctic falcon monitoring sites, present trends for long-term occupancy and productivity, and summarize information describing abundance, distribution, phenology and health of the two species – based on data for 24 falcon monitoring sites across the Arctic. The analyses were published in the journal Ambio (Franke et al. 2020) as a contribution to the terrestrial Circumpolar Biodiversity Monitoring Programme (CBMP) defined by Arctic Council’s Biodiversity Working Group (Christensen et al. 2018).</p> <p>The data compiled from across the Arctic for the analyses by Franke et al. (2020) are here made available for wider usage and comparisons. However, for the analyses in the Ambio paper, some filtering procedures were applied (e.g. time series shorter than 10 sampling years, or fewer than 10 territories monitored), excluding some of the original data that are now made available in this dataset. In addition, some co-authors preferred either to conduct separate uploads of respective data, or declined the invitation to make the data publicly available (see attached map overview of monitoring sites); hence this dataset does not exactly match the data analysed by Franke et al. (2020).</p> <p>This data set contains the annual estimates of peregrine and gyrfalcon ‘occupancy’ and ‘productivity’ in respective monitoring sites; for definitions as well a discussion of challenges in determining, interpreting and comparing those figures across sites with different sampling procedures please consult Franke et al. (2020 and 2017).</p> <p>The file named <strong>Arctic falcons monitoring data - AFSG 2020.csv</strong> contains the annual estimates of occupancy and productivity for peregrine falcon and gyrfalcon along with information on monitoring sites and the principal investigators  as specified in the file <strong>ReadMe_Arctic-falcons-monitoring-data.txt</strong>. <strong>Arctic falcons monitoring data - AFSG 2020.xlsx</strong> contains the same data in Microsoft Excel format.</p> <p>The file named <strong>AFSG-MonitoringSites-with-data.png</strong> provides an overview of  the 24 monitoring sites described in Franke et al. (2020) with indication of which datasets are included here.</p> <p>Please note that:</p> <ul> <li>The dataset contains information on sample size (number of nesting territories surveyed in each monitoring site and year) for some areas only; for areas without sample size more than 10 territories were usually surveyed. However, for interpreting the data, potential users may need to consult the principal investigators for the specific monitoring sites.</li> <li>The dataset lists the principal investigators (and contact details) as respective “data owners”; in addition to the Creative Commons License 4.0 specifications covering this data upload, potential data users are strongly encouraged to contact the data owners prior to using or interpreting the data – for consent and possible co-authorship.</li> </ul>

<p>The Peregrine Falcon (Falco peregrinus tundrius) population in Greenland has been monitored in different survey areas in South and West Greenland since 1972. At visits to Peregrine Falcon nests, eggshell fragments from hatched eggs as well as addled (dead) eggs left behind have been collected with the aim of monitoring the thickness of the eggshells as well as analysing the whole eggs for contaminants. The shell thickness serves as a proxy for the falcons’ exposure to certain persistant organic pollutants, in particular DDT and its breakdown products (see summaries in Cade et al. 1988).</p> <p>This data set contains the raw data on 6665 eggshell thickness measurements of:<br> 1.    Whole eggs from South Greenland 1986-2015<br> 2.    Eggshell fragments from the study area in South Greenland 1981-2019<br> 3.    Eggshell fragments from the study area around Kangerlussuaq in West Greenland 1972-1989</p> <p>The data set contains a mix of measurements of shell thickness including or excluding the eggshell membranes from the same clutch of eggs. Based on those measurements the average membrane thickness is 0.071 mm (SD=0.013) – a figure confirmed by other studies – and this ’membrane factor’ can be added or subtracted for comparisons with other data sets.</p> <p>Further details regarding the sampling areas, measurement methods and the results of trends analyses of changes in shell thickness are provided in Falk et al. (2006 and 2018).</p> <p>The file named <em>1_Data_Eggshell_Thickness_1972-2019.csv</em> contains the raw measurements data and the file <em>2_ReadMe_Eggshell_Thickness_1972-2019.txt</em> specifies the content. </p> <p>The file named <em>3_Rscript_Eggshell_Thickness_1972-2019.R</em> provides an R script for summarizing and plotting the data as shown in the file <em>4_Plot_Eggshell_Thickness_1972-2019.pdf</em></p>