DOI: 10.5061/dryad.nk98sf82t
title: A multiscale analysis of factors influencing Blackpoll Warbler occupancy and abundance during the non-breeding season in eastern Colombia

description: The dataset includes two survey methods to monitor Blackpoll Warbler
 populations and assess habitat structure in tropical ecosystems across
 Colombia. The first method involved surveys conducted along 128 transects
 (regional-scale data), each 100 meters in length and 50 meters in width,
 across multiple sites during two sampling periods (2017 and 2018). The
 transects, situated in both uniform habitats (foothill tropical
 rainforests and terra firma tropical humid forests) and
 transitional/agricultural systems, were surveyed by trained observers
 using visual and auditory species identification techniques. Each transect
 was surveyed at least twice per season, with multiple repetitions to
 reduce biases. The second method, point counts (vegetation and landscape
 scale), was conducted across different habitat types in the Meta and
 Guaviare regions, with points strategically placed to ensure habitat
 homogeneity, at 26 sites using 160 point-count surveys, each within a
 30-meter radius. Both transect and point count data were analyzed based on
 observer and repetition to determine species presence and absence. This
 combined methodology provides a comprehensive understanding of species
 distribution and habitat preferences across different landscape scales.
description: <em>Regional scale data collection
     </em> Surveys were carried out along 128
 transects (6 to 11 transects per site), each 100 m long and 50 m wide, and
 separated by at least 200 m to avoid pseudoreplication (Bibby et al. 2000)
 and spaced equally along available access routes e.g., tertiary roads
 (unpaved), trails and footpaths, between January and March during 2017
 (Sample A) and 2018 (Sample B). Surveys were conducted by four different
 observers trained in species identification by sight and sound. At least
 half of the transects (72) were located in blocks of uniform habitat,
 mainly foothill tropical rainforest (Boyacá-Casanare-Meta) and terra firma
 tropical humid forest (Guaviare), and the remaining transects were placed
 in transitional habitats or agricultural systems (e.g. forest edge,
 shade-grown cacao, cattle pastures; Table S1).
 Transects were surveyed during 10 minutes by one observer slowly
 walking the entire transect and registering the number of Blackpoll
 Warblers encountered. All observations were carried out between 06:00 and
 10:00 h (local time UTC-5). Each site was visited at least twice during
 the same season, with two repetitions of each transect per day, per visit,
 for a total of 8 repetitions per transect between January-February 2017
 and 4 repetitions for transects in Boyacá between February and March 2018
 (Table S1). Observers, as well as the order in which transects were
 visited, were randomized to minimize temporal or observer-based biases.
 Transects were not conducted in weather conditions that might affect
 detection probabilities, like rain or strong winds.
 <em>Landscape scale and vegetation structure data
 collection </em> We selected 26 sites within the
 departments of Meta and Guaviare that included one or more of the focal
 habitat types and established 160, 30-m fixed radius, point
 counts (Ortega-Álvarez et al. 2018), divided equally in 40 points per
 habitat (Fig. 1b). Site selection was carried out to minimize the distance
 between sites (and therefore the effect of broader elevation/precipitation
 patterns) but was driven primarily by the location of properties that
 contained the relevant habitats and granted access. Within properties,
 points were distributed such that the desired habitat was the dominant
 cover in a 60 m diameter around points and that point centers were at
 least 30 m from the edge of the habitat, as well as being 200 m away from
 nearby points (Bibby et al., 2000). Points were surveyed during 10 minutes
 on 6 occasions between January and March 2020 by three different
 observers. Repetitions were carried out over a two-day period, to ensure
 population closure, surveying each point three times a day between 6:00 h
 and 11:00 h (local time). Observers, as well as the order in which points
 were visited, were randomized to minimize temporal or observer-based
 biases. The processed data are presented by transect
 and point for each scale, with the presence and absence for each
 repetition and for each observer.
description: # A multiscale analysis of factors influencing Blackpoll Warbler occupancy
 and abundance during the non-breeding season in eastern Colombia
 [https://doi.org/10.5061/dryad.nk98sf82t](https://doi.org/10.5061/dryad.nk98sf82t) # Description of the data and file structure ``` The processed data are presented by transect:involved surveys conducted along 128 transects (regional-scale data), each 100 meters in length and 50 meters in width, across multiple sites during two sampling periods (2017 and 2018). An by point-count: involved surveys conducted along 26 sites using 160 point-count surveys, each within a 30-meter radius. Both transect and point count data were analyzed based on observer and repetition to determine species presence and absence. ``` ### Files and variables #### File: PointData.xlsx **Description:** Landscape scale and vegetation structure data ##### Variables * State_Province for Colombia: first level territorial units in Colombia, ej: Meta, Guaviare ID Point: identifier for point count Municipality for Colombia: correspond to the second level of administrative division in Colombia Latitude: coordinates in decimals Longitude: coordinates in decimals Elevation (m): elevation above sea level Repetition1: repetition of the observation, processed data of presence/absence Repetition2: repetition of the observation, processed data of presence/absence Repetition3: repetition of the observation, processed data of presence/absence Repetition4: repetition of the observation, processed data of presence/absence Repetition5: repetition of the observation, processed data of presence/absence Repetition6: repetition of the observation, processed data of presence/absence Observer1: initials of the names of the observers, categorical variable Observer2: initials of the names of the observers, categorical variable Observer3: initials of the names of the observers, categorical variable Observer4: initials of the names of the observers, categorical variable Observer5: initials of the names of the observers, categorical variable Observer6: initials of the names of the observers, categorical variable Habitat: short name of sampled habitats, forest, cocoa, citrus, silvopastoral #### File: TransectData.xlsx **Description:** Regional scale data ##### Variables * State_Province for Colombia: first level territorial units in Colombia, ej: Meta, Guaviare IDT:  identifier for transect Latitude: coordinates in decimals Longitude: coordinates in decimals Elevation (m): elevation above sea level Sample: this field refers to the data of the presence/absence repetitions, the fields with NA refer to data that were not obtained. SampleA1  SampleA2 SampleA3 SampleA4 SampleA5 SampleB1 SampleB2 SampleB3 SampleB4 ObserverA1: initials of the names of the observers, categorical variable ObserverA2: initials of the names of the observers, categorical variable ObserverA3: initials of the names of the observers, categorical variable ObserverA4: initials of the names of the observers, categorical variable ObserverA5: initials of the names of the observers, categorical variable ObserverB1: initials of the names of the observers, categorical variable ObserverB2: initials of the names of the observers, categorical variable ObserverB3: initials of the names of the observers, categorical variable ObserverB4: initials of the names of the observers, categorical variable Site : sampling site name Year: sample year ## Code/software R Studio, R, or excel ## Access information Other publicly accessible locations of the data: * NA Data was derived from the following sources: * NA