DOI: 10.5061/dryad.7m0cfxpzh
title: Dataset for: Native versus invasive nest predators in Iceland

description: 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 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) is
 provided, too.
description: 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: Icelandic character set All files called
 strandlina_flakar.xyz have to be put in one folder with the name
 strandlina_flakar together with wfsrequest.txt The file
 S2_jonsson_rickowski_ruland_asgeirsson_jeschke.csv includes all data on
 island sizes, distance to mainland, nest counts and mink and fox
 presence/absence. The file islandNameTable.csv contains
 the same geographic information on islands and additionally its
 coordinates for map creation.
description: # Data for: Native versus invasive nest predators in Iceland *** 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