Batumi Raptor Count (BRC) - Autumn migration data

Jasper Wehrmann1, Folkert de Boer1, Wouter Vansteelant1, Jeroen Creuwels2, Niels Raes3, Frank de Miranda4

1 BRC Foundation, Hannah Arendtweg 84, 1349CM, Almere, Netherlands; 2 Naturalis, PO Box 9517, NL-2300 RA, Leiden, Netherlands; 3 NLBIF, PO Box 9517, NL-2300 RA, Leiden, Netherlands; 4 Stichting DuGof, IJskelderlaan 3, 3941 HS, DOORN, Netherlands

Corresponding author(s): Jasper Wehrmann (jasper.wehrmann@batumiraptorcount.org)Folkert de Boer (folkert.deboer@batumiraptorcount.org)Wouter Vansteelant (wouter.vansteelant@batumiraptorcount.org)Jeroen Creuwels (nlbif@naturalis.nl),  (monitoring@batumiraptorcount.org)

Received {date}; Revised {date}; Accepted {date}; Published {date}

Citation: Combination of authors, year of data paper publication (in parentheses), Title, Journal Name, Volume, Issue number (in parentheses), and doi of the data paper.

Resource Citation

Wehrmann J, de Boer F, Benjumea R, Cavaillès S, Engelen D, Jansen J, Verhelst B, Creuwels JCS, Vansteelant WMG (2018): Batumi Raptor Count (BRC) - Autumn migration data. v1.2. Batumi Raptor Count. Dataset/Samplingevent. http://ipt.nlbif.nl/resource?r=brc-autumn_migration_counts&amp;v=1.2 https://doi.org/10.15468/ur0vnh

Abstract

One of the most important geographical bottlenecks for migrating raptors in the east African-Palearctic migration system is situated between the easternmost tip of the Black Sea and the Lesser Caucasus, just north of Batumi, in the Republic of Georgia (Verhelst et al. 2011).
Since 2008 citizen scientists of the Batumi Raptor Count(BRC) monitor the autumn raptor passage daily from mid August till mid October, collecting also detailed
information about the age and sex of focal species. These data are included in the BRC dataset. This dataset offers a unique baseline for monitoring the state of migrant raptor populations in the east African-Palearctic flyway in the 21st century.
Each season a large number of raptors are counted during the autumn migration count. 
The numbers fluctuate around the million individuals in each season. This dataset represent the data during the 2008-2017 seasons.
A detailed description of the BRC migration count protocol, data management strategy, and the open access BRC dataset in GBIF are provided by Wehrmann et al. (2019). This dataset has been used to analyse changes in the abundance and demography of eight abundant raptor species at BRC between 2011-2017. The resulting research paper is currently in 2nd review and will be shared through this webpage immediately upon publication.

Keywords: Occurrence, Autumn migration, raptor, African-Palearctic flyway, monitoring

General description

Purpose: Monitoring the abundance, demography and timing of migrant raptors and selected threatened species in the East African-Palearctic flyway. In addition the data collected may be useful for studying the influence of weather on diel and seasonal migration dynamics of soaring birds.
Additional information: Information about killed and injured birds during the Autumn raptor monitoring is given in the extension ExtendedMeasurementOrFact. Due to a technical error (which is  under review at GBIF) this extension does not automatically link data in this extension with the occurrence dataset. Therefore these data will not be shown at the GBIF portal. However, these data can be retrieved from DwCA in the file "extendedmeasurementorfact.txt".

Project details

Project title: Batumi Raptor Counts - Autumn migration data
Personnel: Jasper Wehrman
Funding: NLBIF partly funded publication and processing of the BRC dataset to GBIF
Study area descriptions/descriptor: The two count stations are located on hilltops with unobstructed view facing north
into the landscape, and within visible range from each other. Locations are the villages Sakhalvasho and Shuamta, North of Batumi, in the Republic of Georgia, between the easternmost tip of the Black Sea and the Lesser Caucasus.
Design description: Migration counts are performed simultaneously from two count stations to cover the approximately 12km long transect line.

Data published through GBIF: http://ipt.nlbif.nl/resource?r=brc-autumn_migration_counts

Taxonomic coverage

General taxonomic coverage description: Soaring birds and few others such as Roller
Taxonomic ranks
Order: Accipitriformes
Species: Coracias garrulus, Streptopelia turtur, Ciconia ciconia, Ciconia nigra
Common names: Raptors, European Roller, European turtle dove, White Stork, Black Stork

Spatial coverage

General spatial coverage: The bottleneck is situated at the narrowest point between the eastern coast of the Black Sea and the foothills of the Lesser Caucasus, just to the north of the city of Batumi, in the Republic of Georgia.
Coordinates: 41°41'2.4''N and 41°41'16.8''N Latitude; 41°41'56.4''E and 41°48'7.2''E Longitude 

Formation period: mid Aug to mid Oct annually from 2008 till present.

Methods

Method step description: 
- . 	At the end of each day count-coordinators go through the records to check for major errors (using simple criteria such as large flocks of rare birds, or specific age and sex combinations), and where possible correct them by discussing these observations with their daily count team. Observations that are suspect due to insufficient information (for example, a large eagle cannot be identified without being aged) are degraded to a less specific level (large eagle spec.).
- . 	At the end of each season the data is verified with an automated script in the open source R software (R Core Team 2017) that validates each single record, ensures count protocol integrity and changes the identification of the species-level of those records with insufficient information.
- . 	An important final step in the production of the NLBIF data product is to detect all double counts in the overlapping count zones between the two stations. An automated procedure written in R detects potential double counts in different spatial and temporal windows for different species.
Study extent description: The villages Sakhalvasho and Shuamta, North of Batumi, in the Republic of Georgia.
Sampling description: Daily counts from 17st August till 16st October. The daily count period starts at one hour after sunrise and ends two hours before sunset. Counts consisted of continuous monitoring during the count period and recording all occurrences.
Quality control description: Counts are conducted by experienced and less experienced bird-watchers that volunteer to count at least two weeks. Count-coordinators screen, select and schedule volunteers such that each station can be staffed by a team consisting of one coordinator and 6 to 12 counters, depending on migration intensity, diversity and also counter availability. We try to enter records always immediately to enable the double count detection in later phase. Digital photography has become an important tool to aid identification of easily confused species.

Datasets

Dataset description
Object name: Darwin Core Archive Batumi Raptor Count (BRC) - Autumn migration data
Character encoding: UTF-8
Format name: Darwin Core Archive format
Format version: 1.0
Distribution: http://ipt.nlbif.nl/archive.do?r=brc-autumn_migration_counts
Publication date of data: 2020-06-16
Language: English
Licences of use: Public Domain (CC0 1.0)

Metadata language: English
Date of metadata creation: 2018-09-05
Hierarchy level: Dataset

References
Wehrmann J, de Boer F, Benjumea R, Cavaillès S, Engelen D, Jansen J, Verhelst B, Vansteelant WMG (2019) Batumi Raptor Count: autumn raptor migration count data from the Batumi bottleneck, Republic of Georgia. ZooKeys 836: 135-157. https://doi.org/10.3897/zookeys.836.29252
Verhelst B, Jansen J, Vansteelant WMG (2011) South West Georgia: an important bottleneck for raptor migration during autumn. Ardea 99: 137–146. https://doi.org/10.5253/078.099.0203