Baltic Seabirds Transect Surveys

Institute of Ecology of Vilnius University

Dataset credit

Gediminas Vaitkus, Institute of Ecology of Vilnius University


Primary contact Ramunas Zydelis Duke University
Data entry Ei Fujioka Duke University



Seabirds transect surveys were conducted in Baltic Sea from 1992 to 1999. Standard seabird offshore sampling techniques assume that line transect of 300 m width is basically used for counting birds sitting on the water surface, whereas the 'snap-shot' method is used for the counting of flying birds at strongly fixed intervals of time.

Additional efforts were put into studies of the offshore seabird and waterfowl movements. We recorded flying
birds along 1,000 m wide transect over the 'classic' 300 m transect used for calculations of seabird densities
during 'snap-shots'.


The main purpose of our work was to investigate spatial structure and dynamics of the offshore seabird populations and to assess their status in specific conditions of the Baltic Sea marine ecosystem. The main tasks of our work were the following:

-Study species composition, abundance and spatial distribution of seabird populations in different seasons of the year, distinguish dominating species and the most important seabird concentration areas in the eastern Baltic;

-Study community structure of inter-specific assemblages and ecological adaptations of wintering seabird populations;

-Study the processes of spatial dynamics and trends of spatial structure in regional seabird populations within the gradient of winter climatic conditions; and

-Study offshore migratory routes and temporary concentration areas of seabirds in the Baltic Proper.

Supplemental information

[2020-10-01] The following invalid species names were corrected according to the Integrated Taxonomic Information System (ITIS).
Larus ridibundus (176835) => Chroicocephalus ridibundus (824041)
Corvus monedula (179746) => Coloeus monedula (916629)
Little Gull: Larus minutus (176840) => Hydrocoloeus minutus (824065)
Little Tern: Sterna albifrons (176899) => Sternula albifrons (824126)
Mergus albellus (175190) => Mergellus albellus (175196)

[2015-03-24] There were 199 records with a value of "EMPTY" or "empty" in the species column. These records are removed.




Attributes described below represent those in the original dataset provided by the provider.
Only minimum required attributes are visible and downloadable online. Other attributes may be obtained upon provider's permission.

Attributes in dataset

Attribute (table column)Description
transectTransect code
dateDate of observation
timeTime of observation
typeTransect type (1, 2, 3)
vesselShip name
o1Observer name first letters (left)
o2Observer name first letters (right)
statusdefinition not provided
latLatitude of observation
lonLongitude of observation
knotsShip speed (knots)
courseShip course (degrees)
speciesSpecies observed
tsnTaxonomic Serial Number by ITIS
scientificScientific name
commonCommon name
rankTaxonomic rank
numberNumber of animals observed
distanceBand of the transect (1, 2, 3 – inside, 4 - outside)
pattern1 – fly, 2 – sit on the water, 3 – follow the ship
ageAge category of the bird (code)
plumagePlumage (0, 1, 2, 3)
directionFlight direction – degrees estimated as if the ship is heading to the North (360 degrees)
fd_realReal flight direction (corrected according to ship
moultMoulting status (0, 1, 2)
geomGeometry field added by OBIS-SEAMAP
oidUnique ID number (generated by OBIS-SEAMAP)
Marine mammals0
Sea turtles0
Rays and sharks0
Other species11,696
Non spatial0
Non species340
Date, Begin1992-10-18
Date, End1999-03-08
Temporal prec.111111
Latitude54.83 - 58.88
Longitude17.69 - 24.36
Coord. prec.5 decimal digits
Data typeAnimal sighting
EffortYES (ID: 359)
Traveled (km)3,476
Effort hours219
Contr. through
Sharing policy CC-BY-NC (Minimum)
Shared with OBIS
GBIF (via DOI)
See metadata in static HTML
See metadata in FGDC XML
See download history / statistics