Swallowtail Survey Help Please.

Having kept an eye on Swallowtail Butterflies the past two or so years I have noticed what appears to be a worrying decline. I base this idea on observations across Norfolk: Strumpshaw, Hickling, Cockshoot Broad, Catfield, How Hill and other places where Swallowtails used to be abundant. * Cockshoot Broad - saw none at all there this year and could not see Milk Parsley either. * Hickling Broad - they've bulldozed the reed beds where many hundreds of Pupae would have been. No signs at Spring. * Strumpshaw Fen - a few sightings but not as many as last year or year before it seems. * Catfield Common - they report a threat due to water used by farmers ('Natures Home' magazine, Autumn 2014) * How Hill - a few sightings around the site but not that many. Has anyone got any more concise and accurate information please? I am truly worried about the survival of Norfolk's rare butterfly and possibly most beautiful. Is it possible to obtain and plant Milk Parsley seeds form a seed bank? This year I hardly saw any Black... err, White Admiral's either; one at Strumpshaw and one at Dunwich Forest. Are these in decline too?
  • Hi I've had a chat with one of our Butterfly transect leaders Please see his comments below:

    1) United Kingdom Butterfly Monitoring Survey (UKBMS) started for all butterfly species at Strumpshaw Fen in 2008.

    2) We started the swallowtail survey in 2010.

    3) 2009 A good total for all species - the year of the painted lady invasion; about 1000 crossed the sandy wall in an hour!

    4) 2012 was a very wet year.

    5) This year promised to be a bumper year until August's weather change; it also effected the swallowtail second brood numbers.

    6) Unfortunately, our Transect does not include the favored habitat of the white admiral so we only record a very few on our survey. There is nothing to suggest a fall in these numbers though.

    7) Many insects go unrecorded as they are outside the parameters of our Transect route. This together with the fact that recording takes place over an hour and a half per week, it's not surprising that rarities like the silver washed fritillary that visit the fen go unrecorded. It's very much chance and circumstance but if the data is to have credibility we can only record what is there at the time of the survey.

    8) We do have another Transect in operation at Sutton Fen and their swallowtail numbers dwarf ours.

    9) Milk parsley will only grow effectively if the water table and surrounding vegetation is favorable. The swallowtail was fairly common in Cambridgeshire until their fens were drained. Hence the efforts of the RSPB to maintain the  correct conditions for this truly astonishing butterfly.

    Year.      All species total.      Swallowtail total

    2008.            616.                   6.      no dedicated swallowtail Transect in operation

    2009.            1458.                 4.      no dedicated swallowtail Transect in operation

    2010.            446.                   20

    2011.            458.                   30

    2012.            374.                   10

    2013.            1160.                 16

    2014.            1105*.                15

    * incomplete as three more weeks to go

  • In reply to Rachel F:

    Keep up the good work Rachel. I note with interest that the woodland trail trimming has apparently taken out some of the bramble that the "Black Admiral" ;-) used to feed on. Hope this does not affect their numbers; being very few anyway.

    Not as bad as "Norfolk Walkers Trust" who have destroyed a huge swathe of reed-bed and milk parsley area to create a raised bank path, just so they can attract more walkers and more money. Unfortunately for the wildlife, this was *The Best* breeding site for Swallowtails in Norfolk and many hundreds of Chrysalis must have been bulldozed away!