Thrybergh Reservoir Country Park – Friday, 12th August 2020

Leader: Colin Howes
Members attending: Mrs Hillary Hilton
Arrived 2pm departed site 4pm

Hot weather & related WARNINGS:

The MET Office Amber warning of intense sunlight and very high temperatures was accurate, so the shelter provided by the path-side hedgerows and woodland was welcome.

  • Warning signs to keep out of the water due to toxic blue-green algae in the reservoir were reminiscent of similar situation at lake-side sites around Doncaster in 2018 (see The Doncaster Naturalist (2020) 3 (2): 56-57). Despite this, earlier in the week the country park had hosted a wild swimming championship and other swimming events were to follow!


  • After a count-up of Mute Swans, Canada Geese and Street Pigeons at the wildfowl feeding/boat launching area, we set off on an a full anticlockwise circuit of the reservoir.
  • According to an NHS sponsored sculpture exhorting people to walk and keep fit, the round trip was claimed to be about 1¾ miles, with distance markers to enable you to check how far you’d gone … or calculate how far you had to go to get back!

 Records (Comments):

  • Mute Swans: Large summer moulting flock of non-breeding Mute Swans (ca. 45), most of which had been ringed on the right leg with a BTO metal ring and on the left leg with a large DARVIC plastic ring applied by a Yorkshire-based ringing scheme.
  • The Leg rings we managed to record were as follows:

0Y13; 0Y17; 0Y58; 0Y59; 0Y61; 1Y81; 251Y; 252Y; 2Y54; 3Y02; 3Y07; 3Y14; 061Y; 436Y;

736Y; 736Y; 796Y; Y284; Y311; Y329; Y342; Y569; Y628; Y630; Y636; Y638; Y644; Y653;

Y674; Y681; Y717; Y764; Y764; Y765; Y765; Y766; Y767; Y775; Y816; Y817; Y824; Y835;

Y843; Y903; Y908.

  • A database of sightings is maintained for each of the ringed swans and it is fascinating to find out where these birds have travelled and what they’ve been up to in their long lives.

 Wildfowl (Swans, Geese & Ducks) feeding area: The vegetation around the feeding area was highly modified, being dominated by plants capable of withstanding intense wildfowl grazing pressure, down to about 2mm, yet were still able to flower. These included Silverweed (Potentilla anserine), Annual Meadow-grass (Poa annua), Pineappleweed (Matricaria matricarioides), Lanceolate Plantain (Plantago lanceolata) and Bird’s-foot trefoil (Lotus corniculatus).

  • Other plants present included edible but inaccessible plants (plants wedged between limestone blocks) including Wall Barley (Hordeum murinum), Sunflower (Helianthus annuus) and Wheat (Triticum aestivum), the latter two having germinated from bird-seed, and possibly unpalatable species such as Small Stinging Nettle (Urtica urens) and Woody Nightshade (Solanum dulcamara).
  • Experiment: It would be interesting to protect sample areas with wire netting and to monitor the response of the plants to the effect of removing wildfowl grazing pressure.
  • Street Pigeons: The large flock (ca. 100) of feral street pigeons (Rock Doves) focussed around the cafés and the wildfowl feeding area include a high proportion of melanic and ‘fancy’ birds, indicating their origins in local city populations and from AWOL racing pigeons.
  • Dittander: One of the most unusual plants encountered was the large and robust Dittander Lepidium latifolium, a native of coastal areas from Kent to Norfolk which has recently and mysteriously appeared on waste ground in South Yorkshire. Wilmore et al (2011) gives nine sites, with only one in the Doncaster district. Here at Thrybergh Reservoir we located two populations on the path side, one of 15m and a second of about 10m, both possibly introduced on machinery during engineering works on the paths or waterside jetties. Though some plants were still in flower, most had gone to seed, though the large, rubbery, dull grey/green leaves were very noticeable. 
  • Some of you may remember John Scott finding a large colony at the Mother Drain/River Torne confluence washland near Toad Holes Lane, Rossington in 2021.


Thrybergh Reservoir
Country Park. SK4795 

Latin Name  Vernacular Name
Achillia millefollium Yarrow (in flower)
Alnus glutinosa Common Alder
Arrhenatherum elatius False Oat-grass
Betula pendula Silver Birch
Centaurea nigra Knapweed (In flower)
Chamerion angustifolium Rosebay
Cirsium arvensis Creeping Thistle
Cirsium vulgare Spear Thistle
Convolvulus arvensis Field Bindweed (in flower)
Cornus sanguinea Dogwood
Corylus avellana Hazel (in fruit)
Crataegus monogyna Hawthorn (in fruit)
Dactylis glomerata Cock’s-foot grass
Elodea nuttallii Nuttall’s Waterweed
Epilobium hirsutum Great Willowherb (in flower)
Filipendula ulmaria Meadowsweet
Geum urbanum Wood Avens
Glyceria maxima Reed Sweet-grass
Hedera helix Ivy
Helianthus annuus Sunflower
Heracleum sphondylium Hogweed (in fruit)
Hordeum murinum Wall Barley
Hyacinthoides hispanica Bluebell (empty seed head)
Iris pseudacorus Yellow Flag Iris (in fruit)
Lepidium latifolium Dittander
Lotus corniculatus Bird’s-foot trefoil
Lycopus europaeus Gipsywort
Matricaria matricarioides Pineappleweed
Phalaris arundinacea Reed Canary-grass
Phragmites australis Common Reed
Plantago lanceolata Lanceolate Plantain
Poa annua Annual Meadow-grass
Polygonum amphibium Amphibious Bistort
Potentilla anserine Silverweed
Prunus spinosa Blackthorn (in fruit)
Quercus petraea Sessile Oak (in fruit)
Quercus robur Pedunculate Oak (in fruit)
Rubus fruticosus agg. Bramble (in fruit)
Salix cinerea Grey Willow
Salix viminalis Osier
Senecio jacobaea Common Ragwort (in flower)
Senecio vulgaris Groundsel
Solanum dulcamara Woody Nightshade
Sorbus aucuparia Rowan (in fruit)
Stachys arvensis Hedge Woundwort (in flower)
Tammus communis Black Bryony (in fruit)
Teucrium scorodonia Wood Sage
Triticum aestivum Wheat
Tussilago farfara Colt’s-foot
Typha latifolia Reedmace (Bulrush)
Ulex europaeus Gorse
Urtica dioica Stinging Nettle
Urtica urens Small Stinging Nettle
Viburnum opulus Guelder Rose (in fruit)
(Diptera: Cecidomyiidae) Dasineura ulmaria Galls on Meadowsweet
(Diptera: Cecidomyiidae) Dasineura fraxini  Galls on Ash
(Acari: Eriophyoidea) Aceria macrochelus  Galls on Field Maple
Artogeia rapae Small White
Pararge aegeria Speckled Wood
ODONATA (Dragonflies & Damselflies)  
Aeshna juncea Common Hawker
Ischnura elegans Blue-tailed Damselfly
  Sulphur/yellow ‘Blight’ on undersides of  Bramble leaves
  Canada Geese: 105
  Greylag Goose: 1
  Mallard: 37+
  Coot: 17+
  Blackheaded Gulls: 17+
  Street Pigeons: ca 100
  Pied Wagtails: 3
  Lapwings: 21 present on 8th, indicating young birds gathering to migrate. Just 1 immature bird present today (12th Aug.)
  Great Tits (2) at stream-side feeding station on 8th Aug.
  Blue Tits (2) at stream-side feeding station on 8th Aug.
  Robin (1) at stream-side feeding station on 8th Aug.
  Wren (1) at stream-side feeding station on 8th Aug.
  Bank voles (2) gleaning the crumbs dropped by the birds at the stream-side feeding station on 8th Aug.

Wilmore, G.T.D., Lunn, J. and Rodwell, J.S. (2011) The South Yorkshire Plant Atlas.
Yorkshire Naturalists’ Union, Yorkshire & the Humber Ecological Data Trust. York.


Denaby Crags – Friday, 5th August 2020

10:30am to 1:30pm
Section organisers: Tony Sellars (Friends) and Nora Boyle (Nats.)
Present 3 members from the Nats and and 10 members from the Crags Friends.


As with our first meeting on Good Friday, the group met at the Crags Road entrance, split into two groups, one (of 7) walking east to the Lady’s Valley quarry then west along the crags to the allotments, the other group (also of 7) walking west along the wooded paths to Denaby Thicks Historic Woodland,  then back to the allotments where both groups met for a very generous and enjoyable picnic lunch provided by the friends.

Although the Crags extend into at least three Ordnance Survey 1km squares, during this visit we mainly recorded in the 1km square SK5099.

Field Notes:

  • Although the recent heatwave had desiccated much of the Lady’s Valley grassland and many of the flowers were prematurely over, the selection of species we identified here demonstrated why the area had been designated a Local Wildlife Site by the DMBC. This fragment of limestone grassland, nowadays a very uncommon habitat, included species such as:

Tor Grass (Brachypodium pinnatum), Quaking Grass (Briza media), Bird’s-foot Trefoil (Lotus corniculatus), Fairy Flax (Linum catharticum), Field Garlic (Allium oleraceum), Field Scabious (Knautia arvensis), Knapweed (Centaurea nigra), Greater Knapweed (Centaurea scabiosa), Lady’s Bedstraw (Gallium verum) and Restharrow (Ononis repens).

Since we were only here for a few minutes and the precipitous path prevented most of us ‘oldies’ from really getting onto the site, the area would certainly repay further examination by a younger generation of ecologists.

  • Areas of the path-side grassland in the Lady’s Valley area had recently been burned, revealing large numbers of dead snails in the charred debris. To gain an impression of the population density of these molluscs a 1meter square was marked out which contained the shells of 12 Brown-lipped Snails (Cepaea nemoralis) and 1 Garden Snail (Helix aspersa).
  • The fires also revealed numerous discarded drinks cans and bottles. These were speedily collected up by the Crags friends (conveniently equipped with carrier bags for the purpose) and deposited in the nearby litterbins.
  • Topography: From the elevated position at the Lady’s Valley Quarry (about 250ft) it was possible to look north-west across to the Pennine hills, picking out features like the TV/Radio transmitter tower at Emley Moor (at 1,084 feet (330m) it is the tallest freestanding structure in the UK and a Grade II Listed Building !). Looking north we could see the continuation of the Magnesian Limestone ridge with villages such as High Melton (286ft), Barnburgh (158ft), Hickleton (362ft) and Hooton Pagnell (309ft). Looking north-east we could see into the heavily wooded Don Gorge with landmarks like the 21 arches of the Cadeby Viaduct opened in 1909 (another Grade II Listed Building) and the Butterbusk Water Tower built in 1951.

The following plant list combines the records from our two visits (totalling 120 species). Species seen during our August visit are in bold type.

Area 1 = Lady’s Valley & Limestone Crags
Area 2 = Denaby Thicks Wood & Woodland Paths

Flowering Plants
Botanical Name Vernacular Name Area 1 Area 2
Acer platanoides Norway Maple    *
Acer campestre Field Maple    *
Acer pseudoplatanus Sycamore * *
Achillea millefolium Yarrow (in flower) * *
Aesculus hippocastanum  Horse Chestnut * *
Ajuga reptans Bugle    
Alliaria petiolata Garlic Mustard *  
Allium ursinum Wild Garlic (Ramsons)    
Allium oleraceum Field Garlic In fruit. Abundant beside path edges & in grassland *  
Alnus cordata Italian Alder   *
Alnus incana Grey Alder   *
Alnus glutinosa Alder   *
Anemone nemorosa Wood Anemone    
Angelica sylvestris Wild Angelica   *
Anthriscus sylvestris Cow Parsley    
Arctium minus Lesser Burdock (Sticky buds) * *
Arrhenatherum elatius False Oat-grass * *
Artemisia vulgaris Mugwort * *
Arum maculatum Arum (in fruit) * *
Bellis perennis Daisy    
Betula pendula Silver Birch   *
Borago officinalis Borage (Allotments)    
Brachypodium sylvaticum False Brome *  
Brachypodium pinnatum Tor Grass *  
Capsella bursa-pastoris Shepherd’s-purse (in fruit) * *
Cardamine flexuosa Wavy Bittercress    
Centaurea nigra Common Knapweed (in flower) * *
Centaurea scabiosa Greater Knapweed (in flower) *  
Chamaenerion angustifolium Rosebay (in flower) * *
Cirsium arvense Creeping Thistle * *
Cirsium vulgare Spear Thistle * *
Convolvulus arvensis Field Bindweed (in flower) * *
Cornus sanguinea Dogwood (in fruit)   *
Corylus avellana Hazel   *
Cotoneaster horizontalis Rockspray Cotoneaster (Cultivated plant disbursed in bird droppings) *  
Crataegus monogyna Hawthorn (in fruit) * *
Crepis capillaris Smooth Hawk’s-beard (in flower) * *
Cytisus scoparius Broom   *
Dactylis glomerata Cock’s-foot * *
Epilobium hirsutum Hairy Willowherb * *
Euonymus europaeus Spindle (in fruit)   *
Euphorbia helioscopia Sun Spurge   *
Fagus sylaticus Beech   *
Ficaria verna Lesser Celandine    
Filipendula ulmaria Meadowsweet    
Fraxinus excelsior Ash (in fruit)   *
Galium aparine Cleavers * *
Geranium robertianum Herb Robert   *
Geum urbanum Wood Avens * *
Glechoma hederacea Ground Ivy (in flower)   *
Hedera helix Ivy * *
Heracleum sphondylium Hogweed (seed heads) * *
Hyacinthoides non-scripta Bluebell    
Hypericum hirsutum Hairy St John’s-wort    
Ilex aquifolium Holly   *
Knautia arvensis Field Scabious (In flower) * *
Lamium album White Dead Nettle    
Lamium purpureum Red Dead Nettle    
Lathyrus pratensis Meadow Vetchling    
Linum catharticum Fairy Flax *  
Lonicera periclymenum Honeysuckle (in fruit)   *
Luzula camestris Field Woodrush [Good Friday Grass]    
Malus x domestica Apple (in fruit)   *
Malus sylvestris Crab Apple   *
Matricaria matricarioides Pineappleweed * *
Mercurialis perennis Dog’s Mercury   *
Narcissus pseudonarcissus Cultivated Daffodil    
Odontites vera Red Bartsia (in flower) *  
Ononis repens Restharrow (in flower) *  
Oxalis articulata Pink Sorrel (Allotments)    
Phalaris arundinacea  ‘picta’ Reed Canary Grass or Ribbon Grass [Varigated in allotments]    
Plantago lanceolata Ribwort Plantain * *
Plantago major Broad-leaved Plantain * *
Populus sp. Poplar sp. possibly Balsam Poplar   *
Potentilla reptans Creeping Cinquefoil * *
Prunus avium Wild Cherry   *
Prunus spinosa Blackthorn (in fruit) * *
Pteridium aquilinum Bracken * *
Quercus ilex Holm Oak (in fruit)   *
Quercus petraea Sessile Oak (in fruit)   *
Quercus robur Pedunculate Oak (in fruit)   *
Qercus cerris Turkey Oak (in fruit)   *
Ranunculus acris Meadow Buttercup *  
Ranunculus auricomus Wood Goldilocks    
Ranunculus repens Creeping Buttercup * *
Reynoutria japonica Japanese Knotweed [a notifiable pest!]    
Rhamnus cathartica Buckthorn (in fruit)   *
Rosa pimpinellifolia Burnet Rose (in fruit)   *
Rosa arvensis Field Rose (in fruit) *  
Rosa canina Dog Rose (in fruit) * *
Rubus fruticosus Bramble (in fruit) Some are clearly magnificent cultivated varieties. * *
Rubus-idaeus Raspberry   *
Rumex obtusifolius Broad Dock * *
Salix caprea Goat Willow   *
Sambucus nigra Elder (in fruit) * *
Senecio vulgaris Groundsel (in seed) * *
Silene alba White Campion *  
Silene vulgaris Bladder Campion (dead seedheads) *  
Solanum nigrum Black Nightshade (in flower)   *
Sorbus aria Common Whitebeam (in fruit)   *
Sorbus aucuparia Rowan (in fruit)   *
Sorbus intermedia Swedish Whitebeam   *
Stachis sylvatica Hedge Woundwort * *
Stellaria holostea Great Stitchwort    
Stellaria media Common Chickweed    
Taraxacum officinale agg Dandelion sp. * *
Taxus baccata Yew   *
Teucreum scorodonia Wood Sage (in seed) * *
Tilia x vulgaris Lime sp. (in fruit)   *
Tussilago farfara Colt’s foot * *
Ulex europaeus   Gorse    
Urtica dioica Stinging Nettle * *
Veronica chamaedrys Germander of Birds-eye Speedwell   *
Veronica hederifolia Ivy-leaved Speedwell      
Veronica persica Field Speedwell    
Viburnum lantana Wayfaring Tree   *
Viburnum opulus Guelder Rose (in fruit)   *
Vicia sepium Bush Vetch (in fruit)   *
Viola odorata      Sweet Violet    
Viola riviniana Dog Violet    
Scientific Name Vernacular Name
 LEPIDOPTERA (Butterflies)  
 Mantiola jurtina  Meadow Brown: A very abundant butterfly
of grassy areas and hedgerows. Its caterpillars feed on grasses.
Pararge aegeria Speckled Wood: Caterpillars feed on the leaves of False Brome, Cock’s-foot Grass; Yorkshire-fog & Common Couch Grass, all of which grow on the Crags.
Pieris brassicae Large White: Caterpillars feed on members of the cabbage family and are consequently reviled by allotment gardeners.
Polygonis c-album Comma: A butterfly of hedgerows and woodland edges. Its caterpillars (which look like bird droppings!) feed on Nettles, Elm and Hop.
Pyronia tithonus Gatekeeper: A butterfly of meadows, lanes and gardens. Its caterpillars feed on grasses.
Vanessa atalanta Red Admiral: It is a strong migrant, spreading northwards from the Mediterranean each summer to breed. Its caterpillars feed on Nettles and in Autumn it feeds on rotting fruit. The one we saw today was sipping the juice of an over-ripe Bramble.
Cameraria ohridella The Micro-moth ‘Horse Chestnut Leaf Miner’ in Horse Chestnut leaves.
Acrocercops brongniardella Micro-moth leaf miner on oak leaf.
Aceria macrochela Gall mite on Field Maple
Cecidophyes rouhollahi Gall mite on Goosegrass
Eriophyes tilae Gall mite forming ‘Nail Galls’ on Lime leaves
(Hemiptera: Psillidae)  
Phyllopsis fraxini Gall bug (jumping louse) on Ash
(Diptera : Cecidomyiidae)  
Dasineura fraxinea Gall midge on Ash
(Hymenoptera: Tenthredinidae)  
Blennocampa phyllocolpa Gall sawfly on Dog Rose
Cepaea nemoralis Brown-lipped Snail. 12 in area of 1m2 of limestone grassland.
Helix aspersa Garden Snail. 1 in area of 1m2 of limestone grassland.
Rhytisma acerinum Tar Spot on Sycamore leaves

Recorders: Nora Boyle, Colin Howes & Tim Kohler.