Leaf hoppers

On the far south side of the University estate, beyond the Botanic Garden and bordering agricultural land leased to Houghall College, is a wonderful area of sheltered rough grassland that blooms with marsh orchids in Spring before the grasses and taller herbs take over about now. Today the area was absolutely alive with thousands upon thousands of this beautiful little insect - the Green Leafhopper Cicadella viridis. As you walk through the grass they leap and bound in front of you propelled by a flick of the hind legs.

The photograph is of a female. Males have darker blue or purple coloured wings.

Leafhoppers make a living by tapping into the sap in grasses.

Insect Activity

Insects are so numerous and varied that it can seem daunting to even begin to get to grips with them. Yet, there are some fascinating insects right under our University noses and their activity is hotting up with the recent warmer weather. For example, walk any of the paths around and over the rough grasslands to the east of the Science Site and Mountjoy at the moment and these two insects should be easy to find and recognise.

The first is the Scorpion fly. An impressive insect, about a couple of centimetres long, it gets its name because the abdomen of the male curls up at the end rather like a scorpion's tail. Worry not, the upturned end isn't a sting at all but the male reproductive organ. The female’s abdomen is more or less straight by comparison. The second example is a soldier beetle. Beetles are easy to recognise from other types of insect in that most have a pair of hard wing covers that meet in a straight line down the centre of the back.

The photograph below shows how the black wing covers open to reveal the folded up wings which the beetle expands for flight.

Damselflies

The large pond behind Mountjoy 4 hosts at least three different species of damselfly, that begin to emerge in large numbers in early June. This is the large red damselfly, one of the commonest species that will breed in small garden ponds.

Damselflies are smaller, more delicate relatives of dragonflies. Most species spend a year as aquatic nymphs before they emerge for their brief lives as adults.

Males and females often have different colour patterns. This is a male common bluetail.

During mating the male grabs the female just behind her head with the tip of his tail and they fly around in tandem before settling. She then bends her tail forward and grasps the back of his thorax, so they assume this 'mating wheel' configuration. This species is the common coenagrion.

 After mating they remain in tandem, while the female lands and dips the tip of her tail in the water, laying eggs on waterweeds or floating debris in shallow water.

Sometimes prime egg-laying sites can be in short supply. Here five pairs of damselflies are egg-laying at the same location, using a floating dead reed as a landing platform.

Speckled Wood Butterfly

Speckled wood butterflies are relatively new arrivals in North East England, first appearing in Durham city three years ago. The species has been gradually advancing northwards for decades - perhaps in response to climate change. There are four known colonies on the university estate - in the Botanic Garden, along the footpath on the east side of John Snow House (sunlit footpaths are a favourite haunt) on the Science Site, on the east side of the hedgerow opposite the Botanic Garden car park entrance and at the southern end of the North American arboretum, on the southern edge of the university estate. Speckled wood butterflies thrive in woodland glades, where the caterpillars feed on common grasses like cock's foot and Yorkshire fog. There are two broods each year and in a good summer occasionally three, so look out for this attractive butterfly in spring, summer and autumn.

Red Kite

Not too many years ago people would have assumed that you were mistaken if you said that you had seen a red kite over the Botanic Gardens. Not so any more, as a re-introduction programme carried out between 2004 and 2006 in the Derwent Valley just to the north of Durham, released a total of 94 birds in the project known as Northern Kites. Breeding success (the first for 170 years in the NE region) has led to birds expanding out from the Derwent Valley base and therefore we can probably assume that sightings in the skies above the University estate will continue to increase. (A release scheme at the Harewood Estate in North Yorkshire has also produced birds seen in the North East)

Last weekend Steve Ansdell was the lucky chap who watched a red kite circling high in the skies above the Botanic Gardens on two successive evenings. They are truly majestic in flight and even at a distance the profile is unlike anything else that you are likely to see. The long wings and forked tail are distinctive.

If you do see a red kite it is worth trying to get onto them with binoculars as every released bird and most of the young birds have been given a unique combination of coloured and numbered wing tags to monitor progress. The details can be found here.

Finally, if this post has whetted your appetite, there are a number of places in the Derwent valley where you will have a really good chance of seeing a red kite. There is a guide to the best viewing points here.

(Thanks to Phil Gates for the use of his library photos)

Butterbur, Petasites hybridus

These conical pink flower heads, belonging to butterbur Petasites hybridus, appear in large numbers in April all along the riverbank at the Durham University Sports Centre at Maiden Castle. The plant  spreads via creeping underground rhizomes and is unusal in existing as separate-sexed plants. The flower above is male, while the one below is a female. Females are easiest to spot after they have been pollinated, when the flower stalk rapidly elongates and the plant carries tufts of downy, wind-dispersed seeds. After flowering has finished the plants produce very large leaves, that were once dried and used for wrapping butter - hence the common name.

False oxlip

Until the beginning of the 1970s the area on the Science Site around the Library and the Calman Learning Centre was the university botanic garden, adjacent to the Botany Department which was located in the Dawson Building. The primroses that you can find flowering in April alongside the hedge that flanks South Road are a legacy of the old botanic garden and of the research of the late Dr. Jack L. Crosby, Reader in Genetics, who was a notable authority on the genetics of Primula , an expert on plant population genetics and was one of the first to use computers in this branch of plant sciences.

Most of the plants along the hedge are either primroses (Primula vulgaris) or hybrids between those and cowslips (P. veris), which are known as false oxlips Primula veris x vulgaris. True oxlip (P.elatior) is a rare species confined to a diminishing number of woodland locations in the east midlands but false oxlips tend to occur wherever primroses and cowslips grow side-by-side. Where the species overlap plants with every combination of intermediate characters are produced, by a process known as introgression.

There are also some magenta primula species of unknown origin amongst the false oxlips and from time to time this species also hybridises with the false oxlips, producing pink-flowered plants. This exactly mimicks the way in which the garden polyanthus, with its wide range of flower colours, arose.

Chiffchaffs

One of the sure signs that the seasons have turned is hearing the song of the chiffchaff - the first of the incoming summer migrant warblers to arrive at the University. Walking through Great High Wood at lunchtime today I heard my first one this year, chiff-chaffing away in the shrub layer beneath the bursting horsechestnuts and the yet dormant beeches. Its about a week or two later than the first one I heard last year.


Not that long ago you could be sure that you were listening to a tiny brown bird that had just flapped its way to Durham from southern Europe or even Africa but these days you can't be too sure because the number of over-wintering chiffchaffs in the UK has been steadily increasing for some years now. There is a map here on the RSPB web site which shows the north/south divide for over-wintering and I am sure that its a fair bet that the line is moving northwards. In fact I heard one singing in the hedgerow on the east side of the Science site as late as September 29th last year.


By contrast, the willow warbler, which to look at is a dead ringer for the chiffchaff, seems to be a total migrant with no over-wintering recorded at all (map here). It will be a week or two before the first of these little birds arrives in our grounds.

Although the chiffchaff and the willow warbler look so alike, their songs are totally different. You can compare recordings of each on the two web site links.

Greater celandine

This plant, greater celandine, grows in the hedgerow near the Stockton Road entrance to the Science Site, just across the road from the site of the new gateway Building. Unlike the familiar lesser celandine which is a member of the buttercup family, greater celandine is a member of the poppy family and like opium poppies bleeds latex if it's damaged ..... but in this case the latex is bright orange.

Greater celandine is an uncommon plant in County Durham and is usually found close to human habitation. It has a long history of use in herbal medicine, when its caustic latex was used to treat warts, and the plants growing on the Science Site are probably garden escapes.

Treecreeper

Treecreepers are beautifully adapted to hunting for small insects in the bark of trees. Those long, needle shape claws give them the grip they need to climb and hang on the underside of branches and their beak is like a long, curved pair of fine forceps. You can often see them in the Botanic Garden (where this one was photographed on an alder tree on Monday lunchtime) or along the woodland nature trail at the bottom of the garden.

In winter they are most often seen in small flocks of blue tits, great tits and long-tailed tits but from spring onwards they're more solitary. Treecreepers have a characteristic foraging strategy, starting at the bottom of the tree, working their way upwards and exploring every crevice until they're maybe 5 -10 metres above the ground then flying to the base of another trunk and starting all over again. Nuthatches tend to use the reverse strategy, often climbing down trees head-first.

Treecreepers nest behind loose bark on dead trees.

Bulrushes

When the pond behind Mountjoy 2 was formed, at the end of the 1990s, it was delibaterately plants with a wide selection of native plant species, to create a teaching resource and a habitat for the wide variety of animals that would soon colonised it. The northern and eastern edges of the pond are planted with bullrushes (or, to be botanically correct, reedmace).

Bulrushes are unusual plants inasmuch as they flower in autumn and produce their ripe seeds in spring - the exact reverse of the reproductive sequence of most of our native plants - so in March the 'maces' burst open and release drifting clusters of these cottony seeds.

Seven-spot ladybird

This little huddle of native 7-spot ladybirds on the Science Site, still hibernating amongst a cluster of wild cherry flower buds that were just beginning to loosen their bud scales in today's sunshine, make a useful comparison with the superficially similar alien harlequin ladybird, which arrived in Durham last year and which you can find out more about here. The red and black-spotted form of the harlequin has more spots, a more domed body and is noticeably larger.... and we'd like to hear from anyone who thinks they've found one.  

Frogs and Toads

The various ponds throughout the university, in college grounds and in the area behind Mountjoy 2, provide excellent breeding sites for frogs (above) and toads (below). Frogs lay large blogs of spawn in shallow water in spring, while toads deposit long strings of eggs around waterweeds. A very large toad population has developed in the large pond behind Mountjoy 2, which hosts hundreds of toads that emerge from their hibernation sites in Hollingside and Little High Woods in March and migrate to the pond, producing their distinctive barking mating calls when they arrive. By Congregation Day in late June the young toadlets are ready to leave the pond and leave the water to hunt for small insects and slugs in the grasslands and woodlands nearby.

Long-horn moth

This little day-flying moths with disproportionately long antennae breeds at several locations on the university estate, including beside the footpath that runs along the east side of John Snow House towards Hollingside Wood and in the Botanic Garden. Its caterpillars feed on dead birch leaves. Only the males have these long antennae, which they use to detect pheromones emitted by females; often, females have a small swarm of eager males fluttering around them.

Tawny Mining Bee

In spring, from mid-April until mid-May, you'll find what appear to be one centimetre-high 'volcanoes' of sandy soil at many locations throughout the university - including the area around the trees outside the library. They are the entrance holes to the nests of this mining bee, which excavates a chamber underground where it lays its egg and provisions it with pollen collected from spring-flowering plants like dandelion.  The larva develops underground on its subterranean food store, pupates and then emerges in the following spring, to begin the cycle again. This species is an important pollinator of fruit trees and also has a fondness for gooseberry blossom.

Himalayan Balsam

Himalayan balsam was introduced into Britain's gardens in 1839 and has since spread throughout the length and breadth of the United Kingdom, along the banks of rivers. The walls of its seed pods develop internal tensions as they dry out, so when they are ripe they explode at the slightest touch and scatter seeds in all directions. The flowers provide a rich source of pollen and nectar for bees in late summer and early autumn. Until recently it was assumed that the spread of this plant might have a devastating effect on native riverbank wild flowers but recent studies indicate that it has a relatively minor impact, and that removing it could create open habitat for more aggressive and damaging weeds. The plant grows along the bank of the River Wear, especially between Millburngate and Prebends bridges, and there are small colonies on university land - at the top and bottom of 'Cardiac Hill' on the Science Site, for example.

Cowslips

Cowslips have been deliberated planted under the trees on the north side of John Snow House on the Science Site and the dense population that has now developed produces a good crop of seeds, so these attractive grassland wild flowers are steadily spreading outwards from their original site of introduction.

Banded Agrion Damselfly

Several species of damselfly breed in ponds on the university estate but banded agrion damselflies have so far only been recorded from the small stream that runs from Van mildert college pond and through the southern edge of the Botanic Garden. They are most often seen in late June and July. Only the male has these blue-spotted wings - the female's wings are transparent and her body is a duller shade of green. Both can sometimes be seen resting on the beech tree leaves beside the stream at the point where it runs along the edge of the haymeadow in the Botanic Garden. The males defend a short stretch of territory along the stream and perform a courtship dance in front of the females - an aerial ballet that leads her to the site for egg laying.

Common Darter Dragonfly

On sunny days in July, August and early October you are likely to find common darter dragonflies basking on sun-warmed surfaces around the large pond behind Mountjoy 2, between the science site and the Botanic Garden. Dragonflies' large eyes provide almost wrap-around 360 degree vision and the hundreds of separate lenses in each eye makes they very senisitive to anything moving across their field of vision, but if you approach slowly you can usually get a close look at them. During egg laying the male grips the female behind her head with the tip of his tail and they fly in tandem low over the pond edge, with the female dipping her tail in the water to deposit eggs on waterweeds.

Beginner's Birds: Great Blue Coal

This mini feeding station at the rear of the Health and Safety Service building on the Science Site has attracted 14 different species of birds ( and a squirrel). These photos show the commonest 3 visitors - from the top, great tit, blue tit and coal tit.

Although these are common birds around the campus, identification does still confuse people who take only a passing interest in birds.

Here are some key identification pointers:-

Great tit: the chunkiest of the three; very bold white cheeks; strong black mark down the centre of its chest

Blue tit: daintier and...well...blue-ish on its head and back

Coal tit:: dainty - like the blue tit: white cheeks but never as clean and bold as the great tit. Also - look on the back of the head where there is an extra white patch.

Hazel and Alder Catkins

Alder has been planted as an amenity tree at numerous locations on the university estate and its long, pendulous catkins (above) appear very early in February. By the end of summer it develops globular, woody cones that release vast numbers of small, winged seeds that are an important food resource for finches like siskins and redpolls in winter.

Hazel catkins are paler yellow and shorter than alder catkins, and usually open to shed pollen at the end of February. Hazel was planted at several locations on the Science Site in the early 1980s so that its nuts could provide a food resource for red squirrels, which were still common there at that time. At the end of the 1970s it was quite common to see half a dozen red squirrels siting on the wall beyond Hollingside House eating hazel nuts from the small patch of coppiced hazel near the lower end of the Botanic Garden. Sadly, red squirrels are now extinct in almost all of County Durham and the hazel nuts are taken by grey squirrels before they even have a chance to ripen...

Maybugs

About once every three or four years students living in college are sometimes alarmed by these large beetles that fly in through open windows on late spring evenings in Easter term. They're maybugs, also known as cockchafers, and their grubs feed on the roots of grasses in lawns, taking three or four years to reach maturity, so batches of eggs all tend to reach adulthood at the same time. Maybugs fly with their hard wing covers outstretched and their beating wings make a loud buzz as they clatter around rooms, where they're attracted to lights at dusk. The adults feed on flowers and can be notoriously destructive in orchards in Europe. You can find out more about this large beetle and find photos of its subterranean larva here.