GB & Northern Ireland Macro-Moth & Butterfly Distribution Maps to 2019 - 10Km scale

Contents:

• Purpose of this web page
• Record data used for the maps
• Other versions
• How to select and display species maps
• Species comments including verification guidance
• Time of year by latitude charts
• Changing the dot colours
• 10Km square species lists
• Species UK status
• Significant changes to the map pages
• Disclaimer

Purpose of this web page

This web page is intended to provide easily-accessible national distribution information at 10Km scale from National Moth Recording Scheme (NMRS) macro-moth records and the Butterflies for the New Millennium (BNM) records held by Butterfly Conservation (BC), for user-selectable periods from 1900 to 2019, together with record phenology by latitude charts in 10Km bands, for the same periods of years. It is hoped that moth- and butterfly-recorders will find this national feedback useful, whatever local county or region-based mapping is also available to them. The page offers easy and rapid comparison between species. All the data for all species is loaded before the page displays the species density map, and there is no further interaction with the website when a species is selected for display.

This page is based on an earlier 'demonstration' page produced when only pre-2000 BC moth data was available, although that page does include some micro-moths and also more recent data for four counties/areas.

This page is produced by a volunteer member of Butterfly Conservation, Gloucestershire Branch. Local tetrad (2Km) scale moth maps for Gloucestershire were first put on the BC Glos. branch website in 2010 and updated annually. Feedback on those has been very positive and they have encouraged the growing community of the county's moth enthusiasts to send in their records. Hopefully these maps will have a similar effect.

Please note that Butterfly Conservation head office and staff should not be contacted about these maps. Butterfly Conservation has provided NMRS macro-moth records and BNM butterfly records up to 2019 to the National Biodiversity Network Atlas (NBN Atlas) website, where species distributions can be viewed, and optionally restricted to the BC datasets.

Record data used for the maps

Macro-moth distribution data from the National Moth Recording Scheme (NMRS) and butterfly distribution data from the Butterflies for the New Millennium (BNM) Recording Scheme, courtesy of Butterfly Conservation. Records were made available for the period up to 2019 on the National Biodiversity Network (NBN) Atlas website in September 2023. Use of these records is covered by the Creative Commons with attribution non-commercial licence (CC-BY-NC). Butterfly Conservation has NMRS database rights. Recorders retain copyright of their original records. NBN Atlas occurrence downloads at NBN Atlas accessed on 28 & 29 September, 2 & 3 October 2023 (moths) and 21 February 2024 (butterflies).

The NMRS & BNM records available on NBN Atlas are at 2Km or 10Km resolution with records for some species only at 10Km. Records for the Channel Islands had been converted from UTM grid references to Latitude & Longitude for NBN purposes, and back to UTM grid for mapping here. Some of the Channel Islands butterfly records were found to have incorrect lat/long coordinates; those records were ignored for these maps.

Other versions

This version of the distribution maps has a number of map options which are described below. A similar version with both 10Km and 2Km maps is available, and also two much simpler versions which have been designed for use with phones (though they can also be used on a computer). All versions have been used with the Chrome browser on a computer, and the phone versions with Chrome on an Android phone, with at most a few other open tabs on the computer browser and none on the phone. Please read the Disclaimer section below.
### WARNING ### The 2Km & 10Km phone version crashed the browser on an older Android phone (but the 10Km version worked on that phone).

• 10Km & 2Km version
• 10Km phone version
• 2Km & 10Km phone version   See WARNING above

The phone versions can both be used offline in places with no phone signal if you download their HTML files and four map graphics files from the website to your phone's internal memory. The map graphics files are gbilat.png, gbi_north.png, gbi_south.png and gbi_west.png, and these need to be in the same folder as the HTML files.

How to select and display species maps

First wait until the map data has been downloaded from the website into your browser. This can take several seconds, and you will see when it has been completed because the display will then show the species density map. From then onwards you can select and display species maps without any further delays because all the necessary data is already in the browser ready for the maps and charts to be drawn.

To choose a species by name, key in at least 3 characters of the name in either the scientific name box or the common name box. The number of matching names is shown in the drop-down selection choice box below the name boxes; use this to select the species. A unique match results in automatic selection, and the selection box opens automatically if there are at most 6 matches.

Scientific names and ordering follows the main section of the Checklist of the Lepidoptera of the British Isles (ABH: Agassiz, Beavan and Heckford, 2013 and subsequent amendments). No map is given for New Forest Burnet, to protect its only remaining UK site which is in Scotland. Any checklist species with no mappable records are also excluded, as are adventive species in Appendix A of the checklist. Any other inclusions or exclusions are unintentional.

Common names also follow the ABH checklist, except for some moth species with more than one name (in some cases for subspecies or forms). For such species those alternative names which are also shown in the 2019 Atlas of Britain and Ireland's Larger Moths are used here. Any part of the name can be used and matching is not case-sensitive, so for example entering "tig" in the common name box gives a list of the Tiger moths.

You can use the species slider bar above the map to move forwards and backwards through mapped species in Checklist order. Click on the [<<] or [>>] button to move backwards or forwards by one species. Alternatively in some browsers you can use the mouse wheel to scroll through the full set of species maps when the cursor is over the graphics area, or through the set of matching species when the cursor is over the matching names selection box.

The initial map shows the numbers of species recorded for each 10Km square. This map precedes the first species map when using the slider bar, movement buttons or mouse wheel. To see the total number of macro-moth species mapped for a square, move the cursor over that square on the map. With the cursor positioned over a square on the map, you can use mouse clicks (un[Shift]-ed) to move backwards and forwards through the maps of species recorded from that square in the selected years period, or alternatively move through the maps of species not recorded there but recorded in at least the chosen number of adjacent squares (1 - 8) during the selected period. This can be used to identify those species not yet recorded in a particular square but which are quite likely to be present there.

If you want to compare maps for two species (or more), you can use the preset buttons. These are updated automatically as you display different maps. To cycle through several maps for comparison purposes, select each map in turn then repeatedly click on the lowest button for one of these species. Each time you do this the chosen species is moved back to the top button and the others are shifted down by one position so that you always click the same button to see the map for the next species in the comparison group.

If the option is selected by clicking on the vertical bar at the right edge of the parameter selection area, another image area is opened up and maps for the previous two species are shown at half-size in this area. Ignore this option if it makes the display wider than you want it to be. To close the half-size maps, click on the vertical button with < marks (or anywhere else over those maps), to widen it for display of four half-size maps, click on the vertical button with > marks.

You can use the vertical range bar with two sliders to select the earliest and latest year periods to include in the distribution maps and latitude charts. Dragging the upper slider downwards will also move the lower slider down so that they do not overlap, likewise dragging the lower slider upwards will move the upper slider up if necessary. Using these sliders there are 10 different combinations of year periods which can be shown, and the display changes as a slider crosses from one year period to another. The same period options are available for the initial species density map.

Instead of the whole area map and latitude chart, northern, western and southern sections of the map can be shown at a larger scale to make it easier to see the distribution in one area. Altitude shading is available on species maps; this is based on open data from Ordnance Survey (for England, Scotland & Wales, contains OS data © Crown copyright and database right 2018) and from the EU Open Data Portal: the EEA Elevation map of Europe.

Instead of mapping species distribution by year period showing the latest of the selected periods for each 10Km square, you can select the option to show the oldest period for each square. This highlights range expansions during the recent periods. You can also select a map showing the number of years the species has been recorded in each 10Km square, or a map showing Vice County distribution (either the latest of the selected periods, or the earliest). NB Not all of the records contained VC locations, so there are a few mismatches between 10Km maps and VC maps (although in some cases the grid references were used to determine missing VCs unambiguously). The VC locations in some records could be incorrect, because the NBN Atlas description of the dataset states "Location is given as the dominant Vice County for each record in Great Britain; for Northern Ireland a nominated Vice County is selected where more than one overlap the grid square".

Species comments including verification guidance

For many species a comment is shown below its map. In most cases this gives the verification grading from BC's UK Macro-moth Verification Grade Guidelines V1.0.1 (May 2021). Comments based on local experience have been provided for some species.

Gradings for verification of adult moth records are on a scale of 1 to 4, defined as:

1. Species that can be relatively easily identified even by inexperienced recorders with the use of up-to-date field guides. Such records would be accepted without the need for additional evidence if they conform to the normal flight period and geographical range of the species.
2. Species where care is needed for identification. Should not present any difficulty for experienced recorders, but inexperienced recorders may be expected to provide additional evidence in the form of photographs of reasonable quality that show as many of the identification features as possible or, alternatively, a specimen. Even experienced recorders may be expected to provide additional evidence if the record is outside of the normal flight period or geographical range of the species.
3. Species that are difficult to identify. Even experienced recorders may be expected to provide additional evidence, for example a specimen, particularly if the record is outside of the normal flight period or geographical range of the species.
4. Species that can only be identified following critical assessment, often involving dissection and examination of genitalia. A specimen should be retained for confirmation.

Time of year by latitude charts

The chart to the right of the whole area map shows numbers of records for each 10Km of latitude in 4 date periods per month (1st - 7th, 8th - 15th, 16th - 23rd and 24th - end). Adjustments were made to the outline map to align with the chart, rotating Ireland and slightly shifting the Channel Isles. The tick marks outside the left edge of the chart indicate Irish 100Km grid lines.

Time of year by latitude includes records of non-adult stages, but for most species there are relatively few of these and the charts indicate the main flight period(s) for adults. This clearly shows how some species are bivoltine in the south and univoltine in the north. The charts also show how some spring or early summer species emerge noticeably later in the north whilst some autumnal or winter species emerge earlier in the north. Later emergence in the north applies to some high summer species (e.g. July Highflyer, Barred Yellow, Minor Shoulder-knot) whilst earlier emergence in the north also applies to some summer species (e.g. Orange Swift, Six-striped Rustic). The charts indicate significant recent changes in phenology for some species, e.g. Green Carpet now has a second generation much further northwards than in the past.

Changing the dot colours

You can change the dot colours used on the distribution maps, the species density map and the latitude charts, and the changes can be saved to a cookie (if your browser settings allow this) so that they are loaded automatically when you visit the page. Click on the [Colours] button in the top left corner to open a colour selection panel which includes instructions.

10Km square species lists

Below the map you can produce species lists for 10Km squares. [Shift]-click on a square on the map to select it. Using the map options, choose the years period for the list, and whether to list species recorded in the 10Km square or alternatively "target" species not recorded in that square but recorded in at least the selected number (from 1 to 8) of adjacent 10Km squares during the selected years period. Use the radio buttons above the species list text area to choose between moths or butterflies or both; scientific or common names or both, and the separator character between items in each list entry. Then click on the Make species list button.

When you first select a 10Km square it is highlit on the map by pairs of horizontal and vertical lines. [Shift]-click on the same square to leave it selected but remove these lines.

Species lists can be viewed in the text area which should be scrollable. Page searches using Ctrl-f should find entries in the list. The number of species entries in the list is given at the bottom of the list. The list can be downloaded to a file on your computer by clicking the Download species list button; the default filename is set using the 10Km square reference, the years period, and the adjacency requirement if that option is selected.

You can make the map display start with a 10Km square already selected by specifying this at the end of the web page URL address. Append the # character followed by the 10Km square grid reference. So for example, appending #SO81 shows the selection of the square containing most of Gloucester. You can also append the ABH checklist number of a species (after the 10Km square reference) so that the page loads displaying the map for that species, e.g. appending #SO81ABH70.061, or just #ABH70.061 to display the map for Common Carpet.

Species UK status

Significant changes to the map pages

Disclaimer