DOI: 10.5061/dryad.08kprr5fz
title: Abundance and distribution of birds from comprehensive surveys of the Canadian Arctic, 1994-2018

description: Abundance and distribution are critical metrics of population status and
 foundational information for conservation. However, even these basic
 metrics have been difficult to obtain for birds in the Canadian Arctic,
 where costs are high and access is difficult. Here, we present estimates
 of population size and distribution for 24 species of shorebirds and 37
 other species of birds across the Canadian Arctic, using ground-based
 surveys of 2,528 plots surveyed between 1994 and 2018. Plot locations were
 selected by stratified random sampling, within wet, moist, or dry habitat
 categories defined based on satellite remote sensing. Double-sampling was
 used to determine detection rates and correct the estimates to reflect
 birds breeding within the plots. Because this was the first large-scale
 survey effort across Arctic Canada, many of the results provide new
 insights with conservation implications. Nearly all estimated population
 sizes for shorebird species exceed prior estimates, many by several-fold.
 The six most abundant shorebird species were Calidris pusilla
 (Semipalmated Sandpiper), Phalaropus fulicarius (Red Phalarope), Calidris
 fuscicollis (White-rumped Sandpiper), Calidris melanotos (Pectoral
 Sandpiper), Pluvialis dominica (American Golden-Plover), and Phalaropus
 lobatus (Red-necked Phalarope), all with estimated population sizes
 exceeding 3 million (CVs for these species ranged from 0.12 to 0.24).
 Although shorebird densities were much higher in wet and moist habitats,
 the large areal extent of dry habitats meant that 42% of all shorebirds
 were estimated to occupy these dry areas, previously considered to be of
 marginal importance. The estimates of abundance and distribution for the
 37 non-shorebird species are, in many cases, the first ever estimates of
 population size from the Arctic breeding grounds. This new understanding
 of population sizes will have important implications for several current
 conservation programs, such as those where areas are identified as key
 habitat on the basis of the percentage of populations using them.
description: # Abundance and distribution of birds from comprehensive surveys of the
 Canadian Arctic, 1994-2018 Dataset DOI:
 [10.5061/dryad.08kprr5fz](10.5061/dryad.08kprr5fz) ## Description of the
 data and file structure See Smith et al. (2025) for a complete description
 of methods. In brief, the study area is all of Arctic Canada (2,629,390
 km²) as defined in the Northern Landcover of Canada (NLCC; Olthof 2009,
 NLCC 2011). The study area is divided into 12 regions, defined by
 physiographic boundaries, each of which is further subdivided into
 subregions (32 in total) of a size that can be feasibly surveyed by one
 helicopter-supported crew in a single year. Each subregion was then split
 into zones, contiguous areas that included ~12 plots of possibly different
 habitats. Plots were typically 12 ha (300m x 400m) but were 16 ha (400 m x
 400 m) in the early years of the survey. Sampling effort was allocated
 unevenly among strata (defined as areas of like habitat within
 subregions), with more plots surveyed from within strata believed a priori
 to support the most shorebirds based on habitat information. The NLCC has
 15 landcover categories, which were condensed into 3 habitat categories
 (wet, moist, and dry) and 2 non-land categories (water and
 snow/ice). Habitat categories of wet, moist, and dry (believed to support
 high, medium, and low densities of shorebirds, respectively) were assigned
 at the scale of plots, based on interpretation of remotely sensed
 landcover data from the NLCC, which uses 30m pixels derived from Landsat
 data. Plots of the same habitat type in a given zone were referred to as a
 cluster. Thus, a given zone might have clusters of plots in different
 strata (e.g., Wet and Dry habitat plots within the same zone). All
 selected plots were covered by “rapid surveys”, in which observers move
 quickly on foot, counting all birds encountered. Rapid surveys were
 conducted during the birds’ late courtship or early incubation period,
 which varies regionally between late May and early July. If a plot was
 surveyed more than once, a mean count was used in analyses. In addition to
 counts of birds, the analyses rely on information related to plots and
 strata, including cluster and plot areas, numbers of clusters, and area
 survey per subregion and stratum. These data are best accessed directly
 through a GIS, but are provided here for reference. Similarly, the PRISM
 dataset is continually growing and is accessible in full by contacting the
 authors. *Northern Land Cover of Canada, NLCC (2011). Northern Land Cover
 of Canada - circa 2000 description. Canada Centre for Remote Sensing,
 Natural Resources Canada, Ottawa, ON.* *Olthof, I., R. Latifovic, and D.
 Pouliot (2009). Development of a circa 2000 land cover map of northern
 Canada at 30 m resolution from Landsat. Canadian Journal of Remote Sensing
 827 35:152–165.* ### Files and variables #### Files:
 Mean_counts_per_plot.csv, Strata.csv **Description:** The files contain
 rapid survey counts of birds as well as plot, cluster, and stratum
 information used in analyses. ##### Variables ***Mean Counts per Plot***
 Stratum: The stratum name, composed of subregion and habitat numbers. For
 example, 1.2_1 is region 1, subregion 2, habitat 1 Habitat: The habitat
 category assigned at the scale of the plot, based on remotely sensed
 landcover. 1 = wet, 2 = moist and 3 = dry habitat Cluster ID: The unique
 identifier for the cluster, within the stratum  Clus area: The land area
 of the cluster in km² Plot area: The land area of the plot in km² Plot:
 The unique name of the plot AMGP, BASA, BBPL, etc., the mean count per
 survey of the plot for birds of various species following AOU 4-letter
 codes ***Strata*** Stratum ID: The stratum name, composed of subregion and
 habitat numbers. For example, 1.2_1 is region 1, subregion 2, habitat 1
 Area Surveyed: The land area (in km²) within all potential plots in
 surveyed clusters Total Number of Clusters: Total number of clusters
 within the stratum