Surprise discovery in Prislow Woods

Stream dipping in the Bickham Stream, Prislow Woods

I was only slightly late arriving at Prislow Woods and the sound of excited children guided me towards a spot where the stream dipping was already in full swing. A group of parents were gathered on a bank with the children in the stream using nets to explore the water. Suddenly a roar of excitement came from upstream, an eel had been caught. A group of children came splashing down to deliver their prize to County ecologist Bruce Forest who was leading the event. All eyes watched as the eel was transferred to the finds tray and began to swim around. 

This eel could spend 20 years in the stream before return to the sea

This wonderful creature had begun life in the Sargasso sea on the other side of the Atlantic Ocean. Emerging from an egg the larvae can take three years to drift across the ocean to the UK, a distance of 4,000 miles. As the larvae approach the coast they develop into glass eels, then entering freshwater they darken and become elvers. Eels can spend up to twenty years in rivers and streams growing into mature adults before undertaking a one way journey back to the Sargasso sea to reproduce.

The European eel is listed as Critically Endangered, the number of glass eels arriving in Europe has fallen by 95% over the last forty years. So finding several juveniles in the Bickland stream highlights the importance of the conservation work being carried out by several local community groups to safeguard the stream. The Prislow wood group is hoping to receive training from  the South West Rivers Trust that will allow them to monitor the water quality in the stream.

County ecologist Bruce Forest led the stream dipping

Finding the eel was also significant as they have not been recorded in Falmouth before according to the National Biodiversity Network Map, see below. So not only did the children have plenty of fun that day, they also contributed valuable citizen science data.

NBN map showing records for the European Eel (Anguilla anguilla)

The stream dipping was organised by the community group #prislowwoods who carry out conservation work such as the removal of non-native invasive species in the woods. For more information visit their Facebook page at, https://www.facebook.com/groups/962446477276694/

Special thanks to Jennifer Carter for permission to use her photographs.

The Queen Bumblebee - Guest Post by Charlotte Rankin

Here in Cornwall, the milder weather has encouraged some brave bumblebee queens to emerge from hibernation and take advantage of the early-flowering plants here. While we do have some winter-active Buff-tail colonies here, most bumblebee queens have been tucked up underground in a long winter’s sleep awaiting Springtime. While in Summer a queen bumblebee proudly secures a nest of up to several hundred individuals, her first few weeks after hibernation are in fact spent solitarily. During this time she ensures a suitable nest site, sets out on foraging expeditions and begins her role as a mother. All whilst battling with Spring’s uncertainties, of course!

A queen Early bumblebee (Bombus pratorum) on Lesser

Celandine, one of the first bumblebee species to emerge

from hibernation. 

As the Spring sun warms the soil, bumblebee queens in their underground burrows start to stir. Here, a queen bumblebee has spent around seven months tucked up in the earth awaiting the Spring alarm. After warming up and with a morning stretch of all six legs, this determined queen eagerly digs her way out of her little burrow, dusts the soil off her coat and sets off into the fresh Spring air to begin the first of her very busy days.

After this long sleep, she is feeling hungry rather than refreshed. She has spent the last several months relying on her energy reserves and her first thought is to find nectar-rich flowers. At this time of year, flowers may be few and far between, but dandelions or a lucky garden find of Mahonia or heather should do the trick. Once revived, a clean of her proboscis and pollen-dusted eyes, she can now begin her next search for a suitable nest site.

Left to right: Red-tailed (Bombus lapidarius), Tree (Bombus hypnorum), Early (Bombus pratorum) and Buff-tailed (Bombus terrestris) queens. Queens here have been found foraging on crocuses, dandelions and lesser celandines. 

She spends considerable time zig-zaging around, searching diligently for a promising site. Depending on her species, she may take a fancy to an old rodent burrow, tussocky grass if she is a Common Carder (Bombus pascuorum), or even an empty bird box if she is a Tree Bumblebee (Bombus hypnorum)!

Following a queen Early Bumblebee (Bombus pratorum), we see her finally decide on an old rodent burrow. While it’s a ramshackle affair of cobwebs and darkness, it provides just what she needs with nesting material conveniently left behind by the previous occupants. She rearranges the material with her little jaws and legs to form a very snug hollow ball, with a single entrance just large enough for her to pass through. In this cavity, she will create a mass of ‘pollen-paste’, made up of pollen and nectar that she has collected on her foraging trips.

Having decided on her home she will set off to explore her new neighbourhood, excitedly flying to and fro and exploring every nook and cranny. She is in fact familiarising herself to its location to ensure that she can return swiftly after her foraging trips. After a few practice flights, she now knows the way to her new home.

During these foraging trips, she battles with the uncertainties of Spring. While the air may be clear and sunny when she leaves, she often returns to her nest with a very soggy, matted coat. Nevertheless, her hind legs are stuffed with pollen and she quickly resumes to the task of constructing her nest. Having mated the previous Autumn, she lays her first batch of eggs upon this ‘pollen-paste’ mass and seals off the structure with wax, which is in fact only around the size of a pea!

Just like birds, she too incubates her brood day and night. This energetically-demanding task requires a lot of nectar. To prevent her from leaving her brood for too long, she cleverly crafts a small wax pot in front of her and fills this with regurgitated nectar. She sips from this while she incubates her brood, replenishing her little pot when necessary.

After a few days, these eggs will hatch into very hungry larvae. As the larvae greedily eat, the queen replenishes this pollen and distributes a mixture of nectar and pollen amongst them. Once fully grown, the larvae will then each tuck themselves up into a cocoon. The cocoons are arranged such that there is a groove that fits perfectly with the queen’s underside. By stretching out her abdomen and hugging all six legs around her cocoons, she ensures their continual warmth for the next few weeks before her brood are ready to bite through their cocoons as adults.

Their movements hesitant and much like a baby’s first steps, the first of her workers are out. Once they have found their feet (all six of them!), they will fulfil their role as baby bee guardians and take over the collection of nectar and pollen to bring back to the nest. However, the queen’s work isn’t over yet – she has a colony of workers to build!

Charlotte Rankin is an ecologist with a passion for bumblebees that embraces both research and conservation. She is a volunteer for the Cornish branch of the Bumblebee Conservation Trust and last year she created two booklets for the conservation group, Penryn Buzz to promote their Bee Ranger project. She has also helped the charity Buglife in establishing their Urban Buzz project in Falmouth. You can follow Charlotte on Twitter at, @bumble_being

Reflections on 2018

A selection of photos from 2018 - click to enlarge

There are, I am sure, good lessons to be learned from the six months of silence since the last post. While I reflect on what they might be and announce that I will try harder to post more regularly in 2019, let’s take a look at the highlights of 2018.

I will start with the wonderful news that Falmouth Town Council is partnering with the charity, Buglife in the Urban Buzz project. This will see areas of the town planted with wildflowers to help pollinator insects in the town. I am so looking forward to seeing these areas flowering for the first time this year.

Three participants in the 2018 Bug Hunt

As part of the Urban Buzz project last August there was a bug hunt organised by Buglife and the town council in the old parts of Falmouth cemetery. The event attracted families who were given sweep nets and were soon capturing a variety of interesting insects and invertebrates. There were also pooters available to try, these are a bottle with two tubes – one to suck on and the other to collect an insect and place it in the bottle. The hunt was so successful that plans are being made for another one this year.

 The two display boards placed in both parts of Falmouth's old cemetery to raise awareness  of its importance to wildlife and the local community.

A major factor in the success of conservation efforts depends upon raising awareness in the local community. In August the Town Council placed two display boards in both parts of Falmouth’s old cemetery. They inform visitors of its importance to wildlife and the fact that it contains several rare species of solitary bees. They also display information on conservation efforts both in the cemetery and the town.

Apart from being excited over the Urban Buzz project there were two personal recording highlights this year. The first was discovering a new species of bee in Falmouth, Anthophora furcata. Not only was this a new record for this part of Cornwall but it is an interesting bee in that it is one of the few species to make its nest by burrowing into dead wood.

    A male Anthophora furcata, captured and released in a
    garden near Kimberley Park.

My second find was seeing my first European Hornet in Falmouth, only saw one and only once. This is our native species and is impressively large and unlike the Asian Hornet not a threat to beekeepers and their hives. Despite its size it is usually a docile creature that often hunts at night.

 Our native hornet, a new record for Falmouth, will we see
 more of them in 2019?

Another fantastic find was shown to me by Simon Penna, Head of Maintenance for Falmouth Town Council. A number of solitary wasps were making their nests in a dead Ash tree in Kimberley Park. Now although solitary, that is the female usually makes an individual nest some species will share the entrance that then leads to their own nest. This was the case with this species, Ectemnius cephalotes and there were steady streams of female wasps bring back captured flies to the entrance. It was fascinating watching them carry the fly beneath them and manoeuvring it into the hole. Each egg that the wasp lays is provision with several paralysed flies for the larvae to feed on when it hatches. Paralysing the fly keeps it fresh for the larvae, an interesting alternative to refrigeration but please don’t try this at home.

A female Ectemnius cephalotes solitary wasp returns to her

nest with a paralysed fly for her larvae to feed on. As an

adult wasp they will feed on nectar.

Most people only encounter and would recognise social wasps, who like honey bees live in a nest with female workers and a queen. In Falmouth the two species usually seen are the Common wasp (Vespula vulgaris) and the European wasp (Vespula germanica). In October Storm Callum damaged one of the conifers in the lower part of Falmouth cemetery. One of its lower branches was almost completely torn from the tree. This caused a common wasp nest to fall from its original position to be caught lower down. Thanks to the skilful work of the cemetery manager, Matthew Brotherton and the maintenance crew not only was the branch safely removed but the still active nest also survived. This gave a rare chance to see the intricate design of the nest and watch the activity of the common wasps for several weeks until the colony came to the end of its lifecycle.

The Common Wasp nest revealed after the damage caused
to a tree by Storm Callum.

The biggest impact made by the weather this year was made by the beast from the east, an influx of cold air that saw snow falling and settling in Falmouth. The effects of this unusually cold spell in March were immediately seen on tender plants such as Alexander that were hit hard. Many queen bumblebees delayed establishing a nest and new colonies by up to four weeks and many butterfly species appeared later than normal.

  Solitary bee (Andrena fulva) on Alexander flowers. Being

  introduced by the Romans from the Mediterranean, 
  Alexander was hit hard by the unusually harsh weather.

Generally I saw a fall in the abundance of insects this spring and to a lesser extent in the summer. My hope is that it was a result of this cold spell and it is not repeated in 2019 to allow populations to recover. Certainly with local conservation efforts the prospects look very promising for this year. It is though a reminder that climate change is something we all should be concerned about. 

Bumblebee count No.2

My timetable and dismal weather during my free time this week prevented me returning to the bumblebee nest until a week after my last count. Not that the weather was inviting as I began walking to the site, the dark clouds suggested rain and the strong wind was cold. Not surprisingly I saw no honeybees, hoverflies or solitary bees about. Bumblebees generally shrug off bad weather, they are tough determined little beasts.

The only other bee seen was this queen Bombus
terrestris (Buff-tailed bumblebee) feeding on
heather near to the nest.

As I approached the nest the first question in my mind was, would it still be active? No one knows with certainty how long these winter colonies last. Within a couple of minutes a bee arrived and entered the nest so I began setting up my tripod and camera to film the nest.

Filming the bees entering or leaving the nest offers a number of advantages. From the perspective of personal comfort it is preferable to watch a video in the warm than stand outside conducting the count. If my comfort is of no concern, it also offers greater accuracy as the video can be replayed and examined frame by frame. Having video also offers the possibility of recounts and the availability of other people to view it.

It had rained earlier in the morning and bumblebees have a tendency not to collect wet pollen. Out of the forty bees that returned to the nest only one carried pollen. It was debatable whether the bee had collected the pollen, it was spread on its hind legs rather than rolled into a ball as usual. It returned in the last few minutes of filming and may indicated that the flower's pollen was drying out and some stuck to the hairs on the bee's leg.

The other notable observation was that one worker exited the nest but rather than flying away, turned round and re-entered the nest - see video.

Compared to last week, there were less bees seen in a similar time span. This may be due to several possible reasons. The colony size may have decreased or possibly the bee's foraging activity may have been less due to the adverse weather, wet pollen or the difference in the time of day between the two observations.

The only certainty gained by comparing both day's counting is that more data is needed. It seems I have a new task for next week's to do list.

Bombus terrestris nest - Falmouth 3rd March 2017 11.14hrs+
P/N? = unable to distinguish whether bee had pollen due to hind legs obscured 

DUR MINS	BEES IN	BEES OUT	POLLEN	NECTAR	P/N ?	TOTAL
10	6	6	0	6	0	12
13	8	7	0	8	0	15
10	5	5	0	5	0	10
11	6	5	0	6	0	11
14	5	6	0	5	0	11
11	7	6	0	7	0	13
7	3	4	1	2	0	7
76	40	39	1	39	0	79

Counting Bumblebees in Winter

After watching buff-tailed bumblebees (Bombus terrestris) visiting flowers for the last three winters in Falmouth I have gained some insights into their behaviour but many questions remain. Discovering a nest a week ago will help extend that knowledge a little further. By counting the bumblebees leaving and returning to the nest it is possible to speculate how many bees are in the nest. 

Friday 24th February 2017 Bombus terrestris nest - Falmouth, UK 
P/N? = unable to distinguish whether bee had pollen due to hind legs obscured

TIME	DUR MINS	BEES IN	BEES OUT	POLLEN	NECTAR	P/N ?	TOTAL
14.36	12	16	10	5	8	3	26
14.49	10	9	9	4	5	0	18
15.01	10	6	7	1	4	1	13
15.12	10	16	9	5	6	5	25
15.26	10	5	6	0	3	2	11
15.40	11	5	4	2	2	1	9
15.54	11	5	6	4	0	1	11
16.06	6	6	0	1	3	2	6
TOTALS	80	68	51	22	31	15	119

The first thing to consider when looking at the numbers is that about 60% of the worker bees in the colony will remain in the nest doing such things as helping care for the young.

A rule of thumb guide is to take the number seen in ten minutes and times that by four. Taking the peak result would give us 104 bees in the colony with about 42 of these involved in foraging. As can be seen the activity decreased over the time of observations illustrating how varied foraging activity can be. Taking an average of the 10+ minute numbers gives a colony size of 66 bees with 26 workers foraging.

As a ballpark figure we have a colony size of 66 to 104 bees from the initial observations.

Edit 17th December 2017 - Having reflected on these figures I feel they are probably too low. Given that there are fewer flowering plants in winter it is likely foraging flights take longer. Also the frequency of bees visiting plants in various locations suggests a larger colony size although the possibility of there being more than one colony must be considered.

The question is only really going to be answered with a spade once a colony has completed its lifecycle and is disused. Examining winter active nests and looking at its cells where the larvae turn into adult bees will not only give accurate numbers but also answer how many males and queens were produced. 

If you are imagining me standing over the nest for eighty minutes counting the bees while examining each to see if they were carry pollen, possibly wearing a deerstalker hat and smoking a pipe you are mistaken. I filmed the nest - the breaks between counts was due to moving the camera and reframing. Counting was done in the warm, watching and replaying the video while drinking copious cups of tea.

Of course I could not resist making another bumblebee video from 80 minutes of footage - don't worry it is only 2 minutes long.