The Butterflies of our garden & bank at Horncastle

Graphical views

annual-sightings.jpgHere you can see a number of graphs that depict aspects of the species spotted in our garden and the Bund directly behind us.

The first at left is the total number of different species (per year) we’ve seen since 2003. It can be surmised that on average we get 19 species however what it can’t show is that some years we’ve had a different mix of species. So in grand total we’ve actually spotted 23 different species but not all return each year. One, the White Admiral, has only been spotted three times since 2001 (actual records were not begun until 2003 but Paul did make a note of something that looked like the WA).

The following are month/year graphs showing how each month has fared since we began making notes in 2003.


As it is usually the first month we start to see the butterflies emerge then the cumulative count will always match the total species seen during the month. As can be seen we have had a couple of years when no butterflies were seen, 2005, 2006 and 2013. The average number of butterflies seen during March is 3 with a  low of 0 and a high of 6.


Now we see the effects of the cumulative counts begin to kick in as new returns are added to the count from march. Like March the cumulative totals almost keep the same as the monthly totals so at least it is consistent.  The average number of species seen during April is 7 with a  low of 4 and a high of 11. Perhaps this large see sawing over the years is an effect of the weather?


The cumulative totals now begin to climb as more new returning species are spotted. However the average of returns seems to have smoothed out a little with an average cumulative of 10 (low of 8 and high of 12). Monthly total of species spotted is still a bit mixed with an average of 8 and a low (this year sadly) of 5 and a high of 11.


By June the cumulative totals should start to increase as we get an influx of returning species and initially from 2003 until 2011 the average returning species is 14 by the end of June. But as can be seen this drops off dramatically for 2012 and 2013 with a partial recovery for the current year of 2014.  Looking at the normal monthly total of butterflies seen in June there is some variation but after 2010 there is a dramatic dropping off in the number of butterflies seen in our garden and the bund. This may again be due to some poor weather we’ve had during the last few June’s however it also coincides with the area between us and the bund (about 2 metres in width) being mown. The mechanical mower decimates the vegetation, especially the grasses and it’s the lack of butterflies that are associated with the grasses that we’re noticed diminish. In 2013 I (Paul) tackled the company and council involved and this year they didn’t mow our back section. Although it may take a few years to recover we did notice a slight improvement for the number of returning butterflies. Only time will tell.


This month usually see’s the maximum number of different species appear at some time in our garden and bund and like June’s figures the cumulative rate from 2003 to 2010 for July averages out at around 19 different species seen on a typical July but again since 2010 the numbers have fallen off with a low of 15 for the last two years. The actual monthly numbers seem to indicate a longer downwards trend from a high of 19 species for the month (2006) to a current low for the last couple of years of just 9 so we hope 2014 will buck this trend. However there is another factor in all this over the last couple of years adding to the mowing effect mentioned in the June notes. There is a large industrial estate behind the bund (hence the reason for the bund’s existence) and for many years a large section of it to the North East of us was open land that was wild and effectively full of meadow flowers and grasses. It has now been built upon and we suspect this has added to the decline in the local sightings :-(  


This is also another month that normally has a high number of butterflies species spotted but with fewer fresh returns so the cumulative tally tends to remain similar to July. For the overall returns they average out at  19 different species with a high of 21 recorded 4 times since 2003. The actually monthly numbers appear to show a slow decrease from a high of 18 different butterflies in 2004 to a low of 8 in 2012 with a  blip in 2006 when for over half the month we were away on holiday so may have missed some species. Last year saw a dramatic surge in the number of butterflies we saw during August back up to 16 species so fingers crossed for 2014.


This is the month that sees the monthly totals start to fall as the ‘season’ for us is soon to be over. The cumulative tally usually reflects that of August as we only occasionally get a new return but the overall number of species seen during a typical September is fairly consistent. The average monthly total is 8 spotted with a high of 10 and a low of 6.


By October the butterfly season for us is almost at an end and by this month we are lucky if we see even a couple of butterflies. The cumulative is effectively meaningless now as we don’t get any new returns for the year but the number of different butterflies we see during October has shown and interesting overall rise. In 2004 we spotted just 2 butterflies, we had a dip then a rise to 4 then another dip then finally the last couple of years we’ve had 6 species show up! Perhaps this is an indication of generally milder Octobers allowing some of the usual suspects to linger? Only time will tell.


Again this is interesting in the fact that normally we don’t spot any butterflies for this month but in 2009 did see a Red Admiral on Nov 4th!

We’ll still be keeping a sharp look out for any activity however for this year and beyond.

Webmaster © Paul L Money Feb 19