Table 1. Data fields in GAVIA.

Field Name	Field type	Description of contents
‘Field Name’ shows the GAVIA column headings, ‘Field Type’ denotes what kind of data entry is possible for that field, and ‘Description of Contents’ describes what kind of information is recorded in that field. For Field Type, an ‘Autofill box’ is one which is filled in automatically once a new record is created. For example, each new record is awarded its own unique ID number which cannot be chosen or edited. When a binomial is selected, the respective unique species ID and common name boxes are also automatically filled in and cannot be changed or edited unless a new binomial is selected. A ‘Look-up table’ field type means that the information in that box has been selected from an embedded table, for example the taxonomic list or the GADM country list. In other words there are a finite number of selections from which to choose, and the contents of these cells cannot deviate from the contents of the respective look-up tables. A ‘Free Text’ or ‘Free Number’ box means that the data compiler can freely enter whatever text or number that they wish. A tick box provides the compiler with a certain number of selections, for example island type, and the compiler then ticks the relevant box. An ‘EndNote citation code’ relates to the full references recorded in the GAVIA EndNote reference list.
RecordID	Autofill box	A unique number for that particular record. Each corresponding individual map also carries this number. This number never changes, even if previous records are deleted.
SpeciesID	Autofill box	A unique number for each individual species.
Order	Autofill box	The Order to which the species belongs, as per the taxonomy accepted by the IUCN and BirdLife.
Family	Autofill box	The Family to which the species belongs, as per the taxonomy accepted by the IUCN and BirdLife.
Genus	Autofill box	The genus of that species, as per the taxonomy accepted by the IUCN and BirdLife.
Species	Autofill box	The species name of that species, as per the taxonomy accepted by the IUCN and BirdLife.
Binomial	Look-up table	The binomial of that species, as per the taxonomy accepted by the IUCN and BirdLife.
CommonName	Autofill box	The common name of that species, as per the IUCN and BirdLife.
CountryName	Look-up table	The name of the country in which that record occurs as per the GADM designations.
AreaName1	Look-up table	The first sub-level down from country, e.g. region/state, in which that record occurs, as per the GADM designations.
AreaName2	Look-up table	The second sub-level down from country, e.g. sub-region/city, in which that record occurs, as per the GADM designations.
LocationDescription	Free text box	A specific description of where the record occurs, if it cannot be selected from Area Name 1 or 2.
Realm	Look-up table	The biogeographical realm in which that record occurs, as per the Olson et al.17 delineations (Fig. 1).
Island	True/False	Whether the record occurs on an island or not.
LandType	Look-up table	The type of land that the record occurs on, choices being mainland, continental island or oceanic island.
CPrecord	True/False	Whether the record represents a colonisation pressure (CP) location, i.e. a specific location where the species was introduced for the first time, as opposed to a location to which the species has spread.
IntroducedDate	Free text box	The date that the species was first introduced (if known), written exactly as found in the reference, e.g. ‘late 17th century’.
IntroducedDateGrouped	Free number box	The date that the species was first introduced (if known), converted to a number, e.g. ‘late 17th century’ would become 1690. Guidelines were produced to aid this, so that all transformations were consistent (Table 3).
MappingDate	Free number box	The date that the map which corresponds to that particular record represents. For example, the introduced date will stay the same for all individual records from that reference, but as the species spreads over time, the mapped date will change to reflect the newly colonised areas. If there are no dates mentioned at all within the reference, then the date that the reference was published is used as the default mapping date.
ReferenceDate	Free number box	Rarely used. If there is no date of introduction recorded, but the reference referred to is a significantly ‘old’ date, then this is recorded so that it is at least an indication of how long the species has been present in that region.
StatusCat	Look-up table	The status of the species in that record, e.g. established, died out etc. (Table 2).
IntroMethod	Look-up table	How the species was introduced. For example it was released, or it escaped etc.
IntroPurpose	Look-up table	Why the species was introduced. For example it escaped from a zoo, or was released for hunting purposes.
TaxonomicNotes	Free text box	Any taxonomic information relevant to that record.
Notes	Free text box	Relevant additional notes relating to the record that cannot be entered by using one of the above fields, e.g. it might specify numbers of birds released, or specific paths of species spread etc.
RangeMap	Free text box	Whether or not the record has a corresponding distribution map. Either Mapped or Not Mapped. If Not Mapped, it means that it will never be mapped, as the data is deemed too broad scale or vague.
Reference	EndNote citation code	Where the information was found, this links to the full list of GAVIA references (Data citation 1).
CompilerInitial	Look-up table	The initials of the person responsible for compiling that record in the database.