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These web-pages provide information about the 35 butterfly species believed to be resident in Bedfordshire, plus the two additional regular migrants. Species that are occasionally seen but are not believed to breed in the county have been omitted.
Families and Species
The following explains what is to be found on the species pages...
The data were provided by members of the Bedfordshire Natural History Society (BNHS), Butterfly Conservation (BC) and the general public. Thank you to everyone that has submitted records. These web-pages couldn't have been produced without you. Thanks too to those that have assisted with computerising the data, especially Charles Baker the previous County Recorder, who entered and validated the bulk of the data prior to 2003. However, as can be seen from this map showing the distribution of records, coverage is very uneven with many 1km squares having fewer than twenty records and large areas having none at all. As almost anywhere in the county can have about a dozen species passing through it and others may see over 30, this shows that much of the county is still under-recorded, even after so many records have been submitted. There is therefore tremendous opportunity for everyone to contribute knowledge about our butterflies by visiting under-recorded areas and helping to fill in the blanks. There are likely to be unrecorded colonies just waiting to be discovered. See the Recording Butterflies section for how you can get involved. |
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To a degree this reflects the uneven distribution of recording as well as the actual density of species, i.e. note the large number of areas with 12 or less species reported. Again, this shows the value in visiting areas "off the beaten track" in order to enhance our knowledge of Bedfordshire butterflies. |
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Distribution Maps
Distribution maps for each species are presented at a resolution of 1km for all but a couple of especially sensitive (rare) species which are mapped at 5km resolution so as not to provide undue help to those that regrettably may wish to collect our rarer species. (Please report any collecting of these species to the Police Wildlife Liaison Officer). Habitat degradation and site destruction due to development are generally considered greater threats to the loss of colonies than collectors, hence it is thought better to indicate at the 1km square level how sparcely distributed some species are in order to highlight the threats they face. The numbers (9-2) along the bottom of the maps and up the side (2-7) are the Ordnance Survey's 10km gridlines. These allow the 1km squares to be located using OS maps. The Bedfordshire boundary is also shown. The colours of the squares on the maps represent the number of records for that 1km square. Ranges were selected to roughly equalise the quantity for each range. Two sets of maps are provided. One covering the period 1995-2000 and the other 2001-2006, each six years in duration. This allows changes in distribution, abundance, or possibly just recording emphasis, to be observed for each species. On the species pages the two maps can be compared by moving the cursor on and off the map - the map will change as you do so. (Javascript needs to be enabled for this to work). All maps can also be compared on the Distribution Maps page. Where a species was reported as present on a 1995-2000 map, but is absent on a 2001-2006 map, please try to visit the old 1km square and see if you can confirm it is still there - it may simply have been unrecorded in the last six years. There appears to have been a trend in recent years to visit "honeypot" sites, for guaranteed views of species, rather than visiting out-of-the way places to make discoveries, so please try to be a little more adventurous if you can. This map shows the distribution for Large White - move your cursor on and off to see how this common species hasn't been recorded from many "uninteresting" areas in the last six years! |
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Year-by-Year Graphs
Six different graphs are presented on each species page that show different statistics derived from the records. Collectively these can be examined to see what they indicate about the status of the species and how it is changing over time. As many of the records are the product of casual recording (i.e. untargetted and unsystemmatic) it isn't always possible to draw solid conclusions about how a species is faring. Long-term trends may indicate a change in range or abundance, or possibly just recording habits, so use the information with care. The example graph on the right of the number of Wall Browns reported per year however truly does reflect a dramatic and worrying decline in status of this species in Bedfordshire! |
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Flight Time Graphs
The number of records submitted for each week of the year over all the years of data have been totalled and presented as a graph that reflects flight times of the species, e.g. |
The Data
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These can be misinterpreted however. They cover the period from 1995-2003 (nine years) which contained warm, normal
and cool years (or months) therefore the width of a peak in the graph is wider than is likely to be seen in any
one year. This is because warmer weather can advance the flight period by a week or two relative to
a normal year, and a cool period can retard it by a similar amount. [These graphs will eventually be updated to be the range 1995-2006 too, but these things take time!]
The records have also not been processed in any way to reduce the effects of casual recording. Thus if lots of people happened by chance to disproportionately report a species in a particular week then this will result in a bigger spike for that week (and the converse will produce a dip). Also, if a species is particularly abundant in a certain week in one or two years, this can produce a similar spike. Once the limitations of these graphs is understood they can be a useful aid to know when to look for the species on the wing.
Information
Wingspan of adult butterflies vary, so for simplicity have been stated simply as: There are many good books about butterflies available that can provide greater depth if required and make fascinating reading. UK BAP status indicates the current, or proposed, status in the UK Biodiversity Action Plan. These are species whose status causes sufficient concern that action is being taken to conserve it. Priority Status is the highest level of concern (ahead of Species of Conservation Concern, which is the second level). Bedfordshire now has seven Candidate Priority Species, that is, species being proposed to be listed as Priority Species!
Photographs
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Copyright
All material is copyright. Base data are the copyright of the observers and the property of BNHS and BC. Analyses of the data are the copyright of the analyser. Photographs are the copyright of the photographer.
Contacts
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| Keith is the person to contact if you have any comments about these web-pages. | ||