Garden data

Investigating Knoll’s flora and fauna is a key part of the Foundation’s quest to understand the ecology of the gardens. Each year we undertake a number of studies to identify and monitor the plants and animals that live in or visit the gardens and the results of some of these activities are summarised below.

Annual Butterflies, Dragonflies and Damselflies Report 2018

Keith Powrie, an expert in lepidopterology and odonatology, has undertaken regular surveys of Knoll Gardens on behalf of the Foundation since 2009.

The weather this year has been a roller coaster from high to low and back again with several species benefitting from the warm spells while others suffering from the colder ones. However, 2018 saw three ‘firsts’ for the garden.

The first new appearance was a Marbled White which was seen briefly as it shot across to the Mill Pond from the Dragon Pond area on 6th July.

That day was 100% sun, a temperature of 28°C and very little wind. Nine days later, on the 15th July, the second newcomer, a White Admiral, was spotted. Again, there was 100% sunshine, with a temperature of 26°C and no wind at all.

Other notable appearances include the Brown Argus, which normally averages one sighting per year (apart from six being spotted in 2010) but which this year was logged at 30 sightings! Green-veined Whites and Orange Tips took advantage of the early warmth and almost doubled their average counts.

Dragonflies / Damselflies
Most species, apart from the Brown Hawker, whose appearances almost doubled over 2017, were around their annual mean figures. However, the third ‘first’ for 2018 was the appearance of a single male Keeled Skimmer, perched up by Dragon Pond.

The most common damselfly, the Azure Damselfly saw its worst year to date. Only 310 were seen compared to 730 last year and an astounding 1192 seen in 2010, the first year of counting.

The full 2018 report will be available here soon.

Garden birdwatch

male-bullfinchFor several years, regular observations have been made of the birds found in the gardens. One of the ‘stars’ of Knoll birdlife is the resident pair of bullfinch. They are beautiful birds and very easy to spot, usually within 10 metres of the feeder.


The list of birds seen at Knoll between January 2013 and June 2016 can be found here.

Dorset Wildlife Trust Great Heath Garden Survey August 2016

newt1Staff and volunteers from DWT were supported by Knoll’s own volunteers in a garden wildlife survey carried out as part of the DWT Great Heath project.

The team identified 61 species of birds, insects and amphibians in the garden. Birds included Great Tit, Blue Tit, Spotted and Green Woodpeckers, Robin, Chaffinch, Blackbird, Nuthatch, Greenfinch, Songthrush, Goldfinch, Buzzard, Magpie and Bullfinch. Only two amphibians were seen. While one was the Common Toad (Bufo bufo) the presence of an eft (baby newt) was of particular interest.

The full list of species can be found here: Great Heath Survey, Knoll Gardens 2016.

Annual Butterflies, Dragonflies and Damselflies Report 2017

Keith Powrie, an expert in lepidopterology and odonatology, has undertaken regular surveys of Knoll Gardens on behalf of the Foundation since 2009.

dragonfly copy v2

A cool start to spring meant that early-emerging species of butterflies and dragonflies were slow to appear. However, the weather then turned into a roller-coaster of mini heatwaves, followed by wind, rain and cold culminating with a rather disappointing summer.


While the dismal summer brought very low numbers, higher counts early and late in the season lifted the final figures above the annual average. Best performers were the Speckled Wood, with at least one being seen every week, Red Admiral, Meadow Brown and Comma. The Silver-washed Fritillary made a welcome return while Orange Tips and Large Skippers did well.

Dragonflies / damselflies

The warmer spells in late spring meant that both dragonflies and damselflies appeared earlier than in 2016 and numbers exceeded last year’s count. Three uncommon species, not seen last year, made a welcome reappearance in the Gardens; Beautiful Demoiselle (Calopteryx virgo), Emperor Dragonfly (Anax imperator) and Golden-ringed Dragonfly (Cordulegaster boltonii). The disappearance of the Four-spotted Chaser (Libellula quadrimaculata) this year meant that the total number of species in the garden was 15.

The full 2017 report can be viewed here: Knoll report 2017


The weather for 2016 was on the whole worse than 2015. Apart from brief warm spells at the beginning and end of the season the majority of the year was cold, wet and windy. The spring weather started promisingly and early species of butterflies and dragonflies did well. However, came the time for the summer flyers to emerge, the warmth was replaced by cold, damp conditions and numbers were drastically affected.


The total count was down on both the running average and last year. The best performer was the Green-veined White, with a really good second hatching. Next came Brimstone (last year’s winner) and Large White. The recent newcomer, Small Skipper doubled their count from 1 to 2 – not much but a step in the right direction, considering most other species were in decline. Small Coppers did well being up by more than 50% on both last year and the running average.

clouded-yellowAlthough spotted in 2009 but not seen since, the Clouded Yellow is cassified as a new species as the original sighting occured during the first, partial, survey.


The Large Red Damselfly was again the first to emerge however, they were a whole month later than in 2015. Other species appear several weeks later but Azure Damselflies were out and about the following week. Although they were also the most numerous, numbers continue to decline from 620 in two years ago down to 331.


Two uncommon species, a Hairy Hawker and a Downy Emerald, appeared this year. The last time a Hairy Hawker was seen was in 2014 while the last sighting of the Downy Emerald was 2010. downey-emerald

The full 2016 report can be viewed here: knoll-report-2016


2014 was an excellent year for both butterflies and dragonflies and would be a hard act to follow in 2015.


During the early weeks, numbers were often above average. Things continued with around average counts but the warm spell during week 18 produced a count of 57, close to the maximum of 61 seen in 2010. After that the weather changed and counts were below average and sometimes down to previous minimums before a complete turnaround in week 23 with Red Admirals, Painted Ladies, Small Tortoiseshells, Peacocks and Commas appearing in profusion.

The best performer, with a count of 83, was the Brimstone, boosted by a late increase in hatching. Brimstone on Pink

The new species found last year, the Small Skipper, was seen again this year but only a fleeting glimpse. Species not seen this year that have appeared before, were Small Copper, Silver-washed Fritillary, Grayling and Small Heath. The other non-appearer was Clouded Yellow.


Damselflies appeared a week earlier than in 2014, albeit with just a single Large Red Damselfly but they continued on a week longer, until week 23. Both Demoiselle species were seen this year, whereas Banded Demoiselles were absent last year.Azure Damselflies

The most numerous damselfly, once again, was the Azure Damselfly, with a count of 462, compared to last season’s 620.


Dragonflies emerged a week later than they did in 2014, with a single Four-spotted Chaser seen quartering the Dragon Pond. The warmer weather at the start of the season, compared to that of last year, produced a few more dragonflies in the earlier weeks.Ruddy Darter 5

Apart from Migrant Hawkers, the only other species that performed better than in 2014 were the Four-spotted Chasers, who didn’t appear at all last year, and the Emperor Dragonfly.

You can read Keith’s full 2015 report here: Knoll Gardens 2015 report




20 species of butterfly were seen during the 2014 season, producing a total count of 596. This compares favourably with the 18 species and the 397 individuals in 2012.

Week 17 saw the highest count of 84. It was not until the summer finally turned warm in 2012 that a peak of 61 was reached during weeks 23 & 25. The best performer, with a count of 105, was the Peacock with an astonishing second brood figure of 90. One bush contained as many as 15 individuals. Next came Brimstone and Speckled Wood with 76 & 66 respectively. The latter figure was amazing as so few were seen from the spring brood.

For the first time, Small Skippers were recorded. They are species of grassland and it is surprising that they have taken so long to put in an appearance. DSC_0024 small skipper

Holly Blues were up on both broods. This could well be as a result of the fine weather and/or the parasitic wasp being in decline, following a drop in their numbers in previous years.

Red Admiral numbers were down on both broods. During the cold, damp winter many of the overwintering adults obviously perished and the summer fliers were not enhanced by migrants from the continent.

The only species not seen this year, that appeared in 2012, were Painted Lady, Small Copper and Grayling.


The most common damselfly was the Azure Damselfly – up from 581 to 620.

Large Red Damselfly numbers were down, however, from 189 to 114, possibly as a result of losing the Lower Falls Pond due to the fallen Eucalyptus tree. The Blue-tailed Damselfly count had been more than halved, from 22 to 10, probably for the same reason. Only the Beautiful Demoiselle put in an appearance with no signs of the Banded Demoiselle.


Hawkers performed extremely well, showing increases in the number of weeks in which they appeared as well as their actual counts. All that is, apart from the Migrant Hawker, which surprisingly did well at other sites.

The once scarce Brown Hawker continued to increase in numbers and a female was observed egg-laying in the Dragon Pond. Consequently this species can now be added to the list of confirmed breeders at Knoll Gardens. Brown Hawker 1

Only one Emperor and one Golden-ringed Dragonfly were seen throughout the season but this was an improvement on 2012 when neither put in an appearance. Broad-bodied Chasers were up by just one but once again, the usually common Four-spotted Chaser failed to appear. Ruddy Darters showed for the same number of weeks as in 2012 but their numbers were down. To make up for this, Common Darters were everywhere for many weeks and even beyond the end of the season.

Previously seen species that did not appear this year included; Downy Emerald; Scarce Chaser and Black-tailed Skimmer.


You can read the full report via the attached link, but below are the key highlights:

Knoll Gardens Butterfly & Dragonfly report for 2012

The bad weather played a major part in the number of butterflies counted this year. A total of 397 individuals of 18 species were counted, although 146 of these were Red Admirals that came across from Europe in September. This compares to 310 individuals of 20 species in 2011.
The success story of the year was the Orange Tip as it performed well in the adverse weather conditions.

Dragonflies & Damselflies 
Again the bad weather played its part, with emergence 3 weeks later than in 2011. A total of 840 damselflies * dragonflies of 11 species were counted (4 damselflies & 7 dragonflies).
The success story of the year was the Azure Damselfly, with 130 counted in 1 week.


A cool wet summer saw a reduction in previously recorded numbers of butterflies, damselflies and dragonflies.


310 butterflies were counted, representing 20 species. Of these the most numerous were:
Green-veined White – 70
Red Admiral – 46
Speckled Wood – 42
Whilst Holly Blue numbers were down compared to previous years they were still in the top 5 for the whole of Dorset.
Surprise visitor? Green Hairstreak – a heathland species.

Damselflies and dragonflies

875 damselflies and dragonflies were recorded representing 15 species, (5 damselflies, 10 dragonflies).

The Large Red Damselfly increased its numbers from 153 to 211, taking advantage of the warm spring.
Surprise visitor? Scare Chaser – a riverine species – and as its name suggests, scarce!


Monitoring in 2010 saw numerous species added to 2009’s initial list.


500 butterflies were counted, representing 21 species. Of these the most numerous were:

Meadow Brown – 71
Green-veined White – 62
Holly Blue – 62
The Holly Blue count was the highest recorded at all Dorset sites, encouraged by the warm spring and numerous holly trees and ivy in the gardens.
Surprise visitor? Purple Hairstreak – an uncommon butterfly that favours oak woodland.

Damselflies and dragonflies

1500 damselflies and dragonflies were recorded representing 16 species, (5 damselflies, 11 dragonflies). Of these the most numerous were:

Azure Damselfly – 1245
Common Darter Dragonfly – 46
Surprise visitor? Golden-ringed Dragonfly – a riverine species normally seen patrolling streams and rivers.


This was the first survey undertaken in the gardens. Conducted later in the year (August/September) it provided the first available data on butterflies, damselflies and dragonflies at Knoll Gardens.


13 species of butterfly were recorded:
Brimstone, Clouded Yellow, Comma, Gatekeeper, Green-veined White, Holly Blue, Large White, Meadow Brown, Painted Lady, Peacock, Small Tortoiseshell, Small White and Speckled Wood.

Damselflies and dragonflies
5 species of Dragonfly were recorded: Southern Hawker, Brown Hawker, Common Hawker, Migrant Hawker and Common Darter.
4 species of Damselfly were recorded: Azure Damselfly, Common Bluetail, Banded Demoiselle and Large Red Damselfly.

For more information about butterflies and ways to encourage them into your garden, visit the Butterfly Conservation website: