This page provides information about the types of data that are included in the EURING databank (EDB) and about how the index was constructed.
EURING Data Bank
The EURING Data Bank holds copies of recovery records from bird ringing schemes throughout Europe. In the past, the emphasis was on birds ringed and later recovered dead. However, for many purposes such as survival analyses and studies of natal dispersal, recaptures or resightings of living birds are just as valuable. Recently, the number of live records has overtaken the number dead records.
There is, necessarily, always a time lag between a bird being recovered and the processing of that recovery being completed at a ringing centre. Some schemes are able to send their latest recovery data set very regularly to the EDB, some other schemes send very large batches at long intervals. We estimate that the data bank now holds about two-thirds of recoveries from the last decade and over 90% of all recoveries since ringing began in Europe.
Details of the coding scheme that is used for these data can be found here.
EURING welcomes applications to analyse data from the EDB. Details of how to apply for data can be found here.
Contents of the EDB index
This index will be updated approximately annually. At the time of the most recent update of the index, there were recovery histories for nearly 3 million ringed birds and, of these, many have multiple encounter records.
Pairs of maps are provided for all species for which there exists at least one recovery. One map shows the recovery location of birds and the other the ringing locations of these birds. Maps have a resolution of 5° by 5° and the symbols indicating numbers of individuals in each block are logarithmically scaled. There is a similar pair of maps for each species where there exists at least one live recapture or resighting.
In addition to the information for each species there are four summary tables, two for the dead recoveries and two for the live recaptures. In each case there is one table giving the number of records per scheme per decade (live and dead). The tabulation per decade is based on the date of recovery or recapture.
Types of data held in the EDB
The quality of the data in the EDB is variable and for the purpose of making this index, only a very limited amount of checking has been performed (see below). The basic unit for constructing this index is the EDB record. One such record describes one encounter with a bird which may be its first encounter (ringing event) or a subsequent encounter (recovery, recapture or resighting). Here, two types of subsequent records are considered:
- Encounters with living birds, that have been identified through either recapture, or reading the ring or other unique marks from a distance. In these cases, there can be multiple records per individual (White Stork is an example with many records per individual). The first record for an individual is the ringing record and all other records are subsequent encounters.
- Encounters with dead birds. Associated with each recovery record there is a record with the ringing details of that individual. Cases of later reports of the same ring are ignored. There can thus be only one record of a bird recovered dead per individual.
Ringing data are only included for individuals that are later encountered again, alive or dead. It is possible that an individual is encountered alive one or more times and is later encountered dead. In that case, the data for this individual will appear once on the map of ringing locations for birds later recovered dead and it will appear once on the map with the recovery locations. The same individual will appear as often as it has been reported alive on the map of recapture/resighting locations (at the same or different localities) but it will also appear on the map of ringing locations for birds later reported alive as often as it has been reported alive. One extreme example are the data for the Spoonbill for which there are many more resightings than individuals that have been ringed.
Maps of ringing and finding locations
The first step towards map construction was a tabulation of all records for each species in 5° by 5° blocks, both for the ringing and for the finding locations and for live and dead recoveries.
Each pair of maps is accompanied by two tables
The first table gives an overview of the number of records by decade. This tabulation is based on the year of recovery or recapture. All records referring to data before 1940 have been grouped. The data for the last few years are, neccessarily, incomplete and will increase when updates arrive from schemes.
The second table gives an overview of the schemes that have contributed any encounter records for the species. Again, the numbers are blocked in decades.
- Name changes in schemes. This is an index of the data in the EURING Data Bank. The names of schemes appear in the index as they are on the records in the EDB, which in turn corresponds to what is written on the rings. Several schemes have changed names when the countries changed names. For example LIK (Lithuania, Kaunas) was previously SUK (Soviet Union, Kaunas). In some cases schemes have recoded old records - for example DDH (Hiddensee, East Germany) has become DEH (Hiddensee, Germany). In some other cases, older records will not have been recoded.
- Species and subspecies. For a number of species, there are separate codes for subspecies as well as a species code. In this index all subspecies have been combined into the single species pages. The use of subspecies is not consistent among schemes and over time. Some problems may arise if former subspecies have been elevated to species status and given a full species code.
- Schemes and locations. Data are classified under schemes, which are the schemes that issued the ring. Within Europe, birds are normally ringed with rings of the scheme responsible for that area, but there have been exceptions and European rings have also been used in Africa and Asia. Thus, recovery data or recapture data in Africa can also arise from locally ringed birds. The EDB does not routinely collect records of birds ringed in Africa but some records involving the use of European rings in Africa have been included.
- Updates. This index was made on all data in the EURING Data Bank in September 2003. Updates of maps and tables may be expected to be made every year or two.
- Deleted records and totals. The purpose of this index is to give an overview of the data available in the EDB. Some incomplete records have been disregarded in some tabulations, but not in others. This may lead to small discrepancies in numbers between tables or between the information per species and the tables. The most common problem is incomplete spatial co-ordinates. The proportion of problematic records is in the order of 2 per 10 000.
EURING is particularly grateful to the Netherlands Institute for Ecological Research which hosted the EDB from 1977 to 2005.
The EDB is currently hosted by the British Trust for Ornithology.
We are grateful to all of the Ringing Schemes who have contributed to the EDB, without whose efforts this invaluable European dataset would not be available. These schemes in turn are dependent on large numbers of ringers (most of whom are volunteers), birdwatchers and members of the public for the collection of data. We thank all of these people for their contributions.