Swedish Bird Survey: Summer point count routes (Sommarpunktrutterna)

Åke Lindström; Martin Green

doi:10.15468/2aajk9

Swedish Bird Survey: Summer point count routes (Sommarpunktrutterna)

Citation

Lindström Å, Green M, Jönsson A (2024). Swedish Bird Survey: Summer point count routes (Sommarpunktrutterna). Version 1.7. Department of Biology, Lund University. Sampling event dataset https://doi.org/10.15468/2aajk9 accessed via GBIF.org on 2024-12-12.

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 standardised 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 standardised 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 year 2023, and approximately 1200 of these have been surveyed during the summer. The dataset presented here is for the summer 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 summer 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 summer survey should ideally be carried out once per year and in the main breeding season for the majority of species (April-June). The current data contains routes counted from April to mid-July. A route does not have to be surveyed every year. It should ideally be surveyed +/- 5 days from the first survey date, start at the same time of day +/- 30 minutes, and the 20 points should be counted in the same order. 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 are initiated.

Sampling

Summer point count routes consist of 20 separate positions (points), situated at least 200 m apart in dense forest and at least 300 m 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, by bike or moped, by car or motorcycle, other).

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 Summer 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 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 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. 4) 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. 5) Breeding vs migrating birds: The surveyor is expected to report all birds seen or heard. This survey is carried out at the time of year when most birds have just started breeding. One can therefore assume that the very majority of birds that are registered are actually breeding, or attempting to breed, in the location where they were registered. There are however some notable exceptions. Some of the species registered do not breed in Sweden, and are instead migrating individuals; for example Brent Goose (prutgås), Greater White-fronted Goose (bläsgås) and Grey Plover (kustpipare). For some species breeding in the far north of Sweden, individuals are seen further south as they are on their way to or from the breeding grounds. Examples of such species are Bar-tailed Godwit (myrspov), Spotted Redshank (fläckig svartsnäppa) and Wood Sandpiper (grönbena). There are also reports of uncommon species that are yet to be confirmed as breeding in Sweden, but where it is possible that the individual registered was actually breeding at the location. Regardless of which of the described situations applies, all data is included in the dataset, and it is the user’s responsibility to decide how to use the data. 6) Adults vs young of the year: Ideally the surveyor should focus on adult birds but if young birds were counted from the start the surveyor should continue to include them, to make the data within a route comparable. Some birds start breeding early enough for the young to have left the nest at the time of the survey. These young of the year are not normally included in the numbers reported, but for some species it cannot be ruled out that some are indeed included. For the three Loxia species, breeding already in late winter, young of the year definitely constitute a large part of the birds registered.

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 at present. Currently these species are: Black stork (svart stork; Ciconia nigra), 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), Montagu’s harrier (ängshök; Circus pygargus), Peregrine falcon (pilgrimsfalk; Falco peregrinus), Gyrfalcon (jaktfalk; Falco rusticolus), Eagle owl (berguv; Bubo bubo), and 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

Lindström, Å., Svensson, S., Green, M. & Ottvall, R. 2007. Distribution and population changes of two subspecies of Chiffchaff Phylloscopus collybita in Sweden. – Ornis Svecica 17: 137–147. -
Ottvall, R., Edenius, L., Elmberg, J., Engström, H., Green, M., Holmqvist, N., Lindström, Å., Tjernberg, M. & Pärt, T. 2009. Population trends for Swedish breeding birds. – Ornis Svecica 19:117–192. -
Lindström, Å., Green, M., Paulson, G., Smith, H.G. & Devictor, V. 2013. Rapid changes in bird community composition at multiple spatial scales in response to recent climate change. – Ecography 36:313–322. -
Heldbjerg, H. et al 2019. Contrasting population trends of Common Starlings (Sturnus vulgaris) across Europe. – Ornis Fennica 96:153–168. -

Contacts

Åke Lindström
originator
position: Professor
Lund University
Ecology building, Sölvegatan 37
Lund
22362
SE
email: fageltaxering@biol.lu.se
homepage: https://www.biology.lu.se/ake-lindstrom
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://www.biology.lu.se/martin-green

Åke Lindström
metadata author
position: Professor
Lund University
Ecology building, Sölvegatan 37
Lund
22362
SE
email: fageltaxering@biol.lu.se
homepage: https://www.biology.lu.se/ake-lindstrom
userId: https://orcid.org/0000-0002-5597-6209

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
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://www.biology.lu.se/ake-lindstrom
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://www.biology.lu.se/martin-green