Swedish Bird Survey: Winter point count routes (Vinterpunktrutterna)

Åke Lindström; Martin Green

doi:10.15468/n5nuuc

Swedish Bird Survey: Winter point count routes (Vinterpunktrutterna)

Citation

Lindström Å, Green M, Jönsson A (2024). Swedish Bird Survey: Winter point count routes (Vinterpunktrutterna). Version 1.6. Department of Biology, Lund University. Sampling event dataset https://doi.org/10.15468/n5nuuc accessed via GBIF.org on 2024-12-14.

Description

The summer and winter point count routes (“punktrutterna”) are two of several schemes within the Swedish Bird Survey (see below), run by the Department of Biology at Lund University. The point count routes were initiated in 1975 as a standardized method for detecting and reporting changes in the abundance of birds and their distributions in Sweden over time. The point count routes can be surveyed in summer and/or winter.

The surveys are initiated and carried out by volunteer ornithologists who use standardized methods to count birds along routes of their own choice.

More than 3100 point count routes have been surveyed at least once up to and including the winter 2022/2023, and almost 2500 of these have been surveyed during the winter. The dataset presented here is for the winter point count routes.

In this dataset, some information is placed in the table ExtendedMeasurementOrFacts (eMoF), which is part of the Source Archive available to download directly from the dataset’s page here on gbif.org. The Source Archive contains the data exactly as uploaded to gbif (verbatim). Should you choose to download the dataset as GBIF Annotated Archive instead, the data has been interpreted and quality controlled by gbif, but, the data in the eMoF will not be included as the eMoF extension is not yet supported by gbif.

Purpose

National environmental monitoring of birds.

Sampling Description

Study Extent

Geography: The winter point count routes are distributed across the whole of Sweden, and there are routes present in all of the 21 Swedish counties. However, the routes are concentrated to the more populated southern half of the country. Point count routes are personal and the position of the route (and the 20 individual points) is determined by the surveyor who initiates it (a so called “free choice” monitoring scheme). Timing and frequency: The winter season is divided into five survey periods, each lasting for 21 days including three weekends. 1: 5–25 October 2: 10–30 November 3: 19 December – 8 January (the main survey period) 4: 24 January – 13 February 5: 1–21 March The project leaders recommend the surveyor to choose one of three survey plans depending on the amount of time and effort he or she is able to spend (but all survey data are accepted regardless of when within the five periods they are collected): Plan 1: The winter point count route is surveyed just once, and then during period no. 3. Plan 2: The route is surveyed twice, and then during periods no. 3 and 5. Plan 3: The route is surveyed during all five periods. Surveying during all five periods allows the tracking of invasions and other movement patterns. It can potentially also allow calculations of winter mortality. Surveying during period no.5 can also be regarded as an early spring survey of breeding non-migrants as well as provide information about changes in the arrival of early migrants. Surveys should preferably be undertaken +/- 5 days of when it was done in year 1. Surveying should start at the same time in relation to sunrise as on the first occasion it was surveyed, +/- a maximum of 30 minutes, and it is recommended to start early morning. The 20 points should be surveyed in the same order every year. A route does not have to be surveyed every year. Since the routes are (in the vast majority of cases) personal, they are no longer counted once the surveyor stops counting this particular route. Following the same principle, new routes can be initiated.

Sampling

Winter point count routes consist of 20 separate positions (points), situated around 300 m or more apart in dense forest and around 400 m or more apart in open terrain, to minimize the risk of double-counting. Birds are counted while the surveyor is standing still for 5 minutes at each point. All birds seen or heard shall be registered no matter how near or far from the point they are. Only birds identified to species shall be included, except crossbills that may (when necessary) be registered at the genus level. The surveyor’s method of transport between points is also registered (on foot or skis, by bike or moped, by car or motorcycle, other). The amount of snow on the ground is also registered (bare ground, snow covered ground, very thin or patchy cover of snow).

Quality Control

Data is checked and validated by the project leaders, specifically species identity, numbers and geographical location. Confidence in the data is good.

Method steps

See sampling description.

Additional info

Important information for potential users of the Winter point count route data: 1. The data shown in this Darwin core archive are, for each bird species, the sum total of all individuals on all the 20 points during this visit. 2. Null visits and zero observations: Users of the data have to construct zero data for each species themselves. The occurrence table contains observations of species that were actually present at the surveyed sites, but the surveyor would have looked for all species that are included in the survey design. For visits to sites where no observations were made at all (when such null visits exist), the occurrence table also includes one zero observation with vernacularName set to "SpeciesIncludedInSurvey", and occurrenceStatus set to "Absent". This is to ensure that information about surveyor is included in the DwC-A also for these events. Additionally, information about whether a visit is a nullvisit (i.e. true = no survey species observed) or not (i.e. false = one or more survey species were observed) is included in the ”extended measurement or fact table”. 3. The coordinates supplied are for the central point of a 25 x 25 km survey grid square, within which most of the points of the route are located. 4. The design of the survey program relies on each surveyor choosing his or her own route to count birds on. This means there is some overlap between some routes, both geographically and timewise. For the majority of routes, especially older ones, the only geographic information available about the route’s location are the midpoint coordinates of the 25 x 25 km square within which most of the points are located (supplied in the dataset). For this reason, it is impossible to know the exact amount of overlap. The exact position are known from a few very old routes, but not until the early 2000s were the positions of all 20 points asked for (also retrospectively). Since around 2005, coordinates for each of the 20 points are requested from the surveyor for all new routes. These are at present not supplied in the dataset, but are available upon request from the data provider. The original design also relies on data from a particular route being entirely comparable between years, i.e. all data collected on a route is collected by the same person. Hence, in the few cases where a route has been taken over by a new surveyor, the route has been given a new id. 5. Habitat data: As part of the original survey program design in 1975, surveyor were asked to register the amount of different habitats at each of the twenty points on the route. This information was regularly updated for some routes but not for others. Since around 2015 requesting this information stopped and instead coordinates for each of the twenty points were requested. This enables a potential user of the data to extract habitat data from a source of their own choice. But point coordinates are not available for all routes (see above), and never will be for those where the surveyor did not, or can no longer, supply the information. The habitat data is available upon request from the data provider.

Taxonomic Coverages

All bird species in Sweden occurring naturally in the wild are included in the survey. Species with a security class 4 or higher (according to the Swedish species information centre (Artdatabanken)) are not shown in this dataset. Currently these species are: Lesser white-fronted goose (fjällgås; Anser erythropus) Golden eagle (kungsörn; Aquila chrysaetos) Spotted eagle (större skrikörn; Clanga clanga) White-tailed eagle (havsörn; Haliaeetus albicilla) Pallid harrier (stäpphök; Circus macrourus) Peregrine falcon (pilgrimsfalk; Falco peregrinus) Gyrfalcon (jaktfalk; Falco rusticolus) Barn owl (tornuggla; Tyto alba) Eagle owl (berguv; Bubo bubo) Snowy owl (fjälluggla; Bubo scandiacus) White-backed woodpecker (vitryggig hackspett; Dendrocopos leucotos)

Animalia
common name: Animals rank: kingdom
Chordata
common name: Chordates rank: phylum
Aves
common name: Birds rank: class

Geographic Coverages

All data is collected within Sweden.

Bibliographic Citations

Contacts

Åke Lindström
originator
position: Professor
Lund University
Ecology building, Sölvegatan 37
Lund
22362
SE
email: fageltaxering@biol.lu.se
homepage: https://portal.research.lu.se/en/persons/åke-lindström
userId: https://orcid.org/0000-0002-5597-6209

Martin Green
originator
position: PhD, Researcher
Lund University
Ecology building, Sölvegatan 37
Lund
22362
SE
email: fageltaxering@biol.lu.se
homepage: https://portal.research.lu.se/en/persons/martin-green

Åke Lindström
metadata author
position: Professor
Lund University
Ecology building, Sölvegatan 37
Lund
22362
SE
email: fageltaxering@biol.lu.se
homepage: https://portal.research.lu.se/en/persons/åke-lindström
userId: https://orcid.org/0000-0002-5597-6209

Martin Green
metadata author
position: PhD, Researcher
Lund University
Ecology building, Sölvegatan 37
Lund
22362
SE
email: fageltaxering@biol.lu.se
homepage: https://portal.research.lu.se/en/persons/martin-green

Annelie Jönsson
metadata author
position: PhD, Researcher
Lund University
Ecology building, Sölvegatan 37
Lund
22362
SE
email: naturdatavardskap@biol.lu.se

Mathieu Blanchet
programmer
position: IT
Lund University
Ecology building, Sölvegatan 37
Lund
22362
SE
email: mathieu.blanchet@biol.lu.se

Åke Lindström
administrative point of contact
position: Professor
Lund University
Ecology building, Sölvegatan 37
Lund
22362
SE
email: fageltaxering@biol.lu.se
homepage: https://portal.research.lu.se/en/persons/åke-lindström
userId: https://orcid.org/0000-0002-5597-6209

Martin Green
administrative point of contact
position: PhD, Researcher
Lund University
Ecology building, Sölvegatan 37
Lund
22362
SE
email: fageltaxering@biol.lu.se
homepage: https://portal.research.lu.se/en/persons/martin-green