Batumi Raptor Count (BRC) - Autumn migration data

Study Extent

The villages Sakhalvasho and Shuamta, North of Batumi, in the Republic of Georgia.

Sampling

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

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.

Method steps

1. 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.).
2. 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.
3. 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.

Soaring birds and few others such as Roller

1. Accipitriformes
   common name: Raptors rank: order
2. Coracias garrulus
   common name: European Roller rank: species
3. Streptopelia turtur
   common name: European turtle dove rank: species
4. Ciconia ciconia
   common name: White Stork rank: species
5. Ciconia nigra
   common name: Black Stork rank: species

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.