Common eider (Somateria mollissima) nest counts in Breiðafjörður Bay in West Iceland in the two archipelagos Brokey (95 islands over 123 years) and Purkey (39 islands over 27 years) along with size information on islands and several measures of their distance from mainland. Information on presence/absence of invasive American mink (Neogale vison) and native arctic fox (Vulpes lagopus) as well as the Atlantic Multidecadal Oscillation index (AMO) are provided, too.
All islands were visited over the span of 1–2 weeks every breeding season each year, depending on weather and the number of people available. For Brokey and Purkey, nests were counted and located by 6–12 and 2–5 people per year, respectively. The only years missing are the years 1946–1950 in the Brokey archipelago.

Description of the Data and file structure

In addition to nest counts, the following information is provided for each island in separate columns: Area (in square metres), shoreline length of the respective island (in metres) and different measures of distance from mainland (straight line or total swimming distance, both given in metres, and the number of swims required to reach the island) as well as fox-accessibility for the Purkey archipelago (shaped by tidal currents in the bay).
For every year, the climate indices Atlantic Multidecadal Oscillation and North Atlantic Oscillation are given as well as the presence of American mink (Neogale vison) and arctic fox (Vulpes lagopus). All this information is contained in the file S2_jonsson_rickowski_ruland_asgeirsson_jeschke.csv
In order to create the map, all files called strandlina_flakar.xyz have to be put in one folder with the name strandlina_flakar together with wfsrequest.txt before the code is run. The file islandNameTable.csv contains the same geographic information on islands and additionally its coordinates for map creation.
The Icelandic character set is used.

Parameter list:
area – area of the respective island in sqm
shoreline – length of the shoreline of the respective island in m
amo – Atlantic Multidecadal Oscillation index
nao – North Atlantic Oscillation index
foxAccessible – foxes can reach the island (0|1)
foxPresent – foxes are present in the general area (0|1)
minkPresent – minks are present in the general area (0|1)
swims – number of swims between mainland and target island
totalDistance – the total swimming distance from mainland to the island in m
longestDistance – the longest swimming distance between any two islands on the way in m
distanceFromMainland – the shortest possible straight distance between the mainland and the island in m

Sharing/access Information

Links to other publicly accessible locations of the data: NA

Was data derived from another source? No
If yes, list source(s): NA