The best sighting of the month was undoubtedly Vic’s battered Swallowtail in Cherry Hinton, which nearly caused her to crash the van! (She assumed it was a migrant from a European population, though it might have been raised locally: Wicken Fen has tried to re-introduce them.) I gather: “The British race is the subspecies Papilio machaon britannicus, which is confined to the fens of the Norfolk Broads. This is partly due to the distribution of the sole larval food plant, Milk-parsley. In some years, there are reports of the P.m. gorganus subspecies arriving from the continent. This is less fussy and will use many kinds of Umbellifer as the larval food plant.”
Other butterflies include Jeff’s Small Copper, Brimstone and Common Blue; Mary’s Speckled Wood, Guy’s Small Copper, Small Heath and probable Small Blue and best of all, Paul’s Clouded Yellow, the last few all being at Trumpington Meadows.
Dragons and Damsels are still around: Jeff reports a Brown Hawker and at least 3 Willow Emerald Damselflies at Paradise pond (also present along Jesus ditch). The Botanic Garden is a hotspot for Odonata and the pond is full of nymphs of different species. The most interesting find here was an Emperor Dragonfly nymph, with its black and white banding (Duncan).
The BioBlitz at the Botanic Gardens was a great success. Dr Lynn Dicks, a visiting researcher from UEA Department of Zoology, pointed out all the different bees and wasps to be found there. Colletes hederae, the Ivy bee, were in the Systematic Beds, the females burrowing into the bare soil around the plants. Though solitary nesters, they aggregate, nesting close together. These bees first turned up in 2001 in the South of the UK and are now widespread.
A Grange Rd garden turned up a splendid but unwelcome Scarlet Lily Beetle and a splendid and most welcome Cream-spot Ladybird (Paul); also, a small Soldier fly – the Dull Four-Spined Legionnaire. Sam reports a Silver-Y Moth and there are increasing sightings of the dreaded Boxmoth: beautiful but deadly! Better news was a Humming-bird Hawkmoth in Newnham (Pam).
Rhona (Jesus College) is always on the lookout for something new: this month a very rare medium-sized Ground Bug Raglius acuminatus with striking red-brown and white markings on the forewings and rear third of the pronotum. A couple of other bugs turned up: a Brassica Shiedbug Eurydema oleracea (nymph) and this bright coloured Cinnamon Bug which startled its host (Andrew). Finally, Paul warns of the dangers of long grass, sending a picture of a Deer Tick before a feed. Although tiny (2-3mm) they may transmit Lyme’s Disease. (This one was (out of our area) at Fulbourn Fen.)
Hirundines gradually reduced in numbers over the first half of the month. Swifts, always the first to go, were last seen on 4th, a few House Martins lingered until 10th and Swallows until 24th (Jeff). Guy reports a Cetti’s Warbler in song and I heard Chiffchaff calling. This seems to happen in the autumn – are they looking for company for the voyage or (someone suggested) is it more to do with the day length being the same as spring? Jeff reports other migrants: 2 Whinchat, 10 Blackcaps, juvenile Lesser Whitethroats along Barton Rd and a couple of Willow Warblers.
Grantchester Rd fields seem to be a good place for Grey Partridges (20) and Jeff saw 80 Linnets there too. Guy noted 5 Gadwall, Great Crested Grebes and Tufted Ducks at Cherry Hinton Lakes. There has been a gradual build-up of Rooks and Jackdaws in the tall trees of Paradise Island – always a sign of autumn for me. St Luke’s Church has been a good spot for Peregrine watching: one harried a flock of pigeons for 5 minutes before effortlessly snatching one mid-air (Ben). Holly’s list of 21 species in Cherry Hinton includes Greenfinches (returning after an absence of several years) and 6 out of 7 surviving Cygnets. My local Swans (new parents) had only one, which has survived and lives with Mum, Dad seemingly bored with parental duties. At Jesus Lock, Rufus saw a young male Swan apparently deliberately slide down the weir!
A few mammal reports: a Water Vole in the brook along “Snakey Path” (Holly), 3 Hares and a Stoat at Nine Wells LNR, a Weasel at Barnwell West and a Field Vole at Hobson’s Park (Guy). Jenny says, “Not an exotic visitor, but I now know who is ripping the heads off the sunflowers I leave to go to seed in the garden for the birds”.
Jonathan says, “Probably the most exciting Botanical find this month was in the River Cam along Stourbridge Common.” There are two species of Water-milfoil that are commonly seen in Cambridgeshire. The Whorled one, Myriophyllum verticillatum produces “turions”, vegetative growths that allow the plant to survive over winter, whilst the other does not. Both are threatened species in Cambridgeshire. Using a small fallen branch as an improvised fishing rod, he fished some out, finding some Water-milfoil with two large turions. Why the excitement? – this plant hasn’t been reported in the NatHistCam area for over 100 years.
Other Botanical highlights included Fox and Cubs Pilosella aurantiaca (Monica), the Small Teasel Dipsacus pilosus, and an alien Goosefoot Chenopodium gigantium on Empty Common (Liza).
Guy reports 3 Grass Snakes in the contractors yard at Hobson’s Park. Meanwhile, in Milton, Clarke has been adopted by one. At the end of July, he found it inside the ‘barn’ – it put on a ‘threatening’ display and hissed at him! A week later, a kerfuffle just outside the back door found the Snake on the patio chasing a Frog, which it caught and proceeded to eat over a period of 11 minutes. Later in September, he found it swimming in the small pond. At some points, there were almost daily sightings, though none now since 15th September 2020. He hopes it will return.
Another enchanting story: Gleb was visited by a Frog, which availed itself of the invitation of an open door, hopped inside and began climbing the staircase! Although escorted outdoors, it stayed put on the grass. A week or two later, it was again in the porch – looking rather menacing, with glowing white eyes. (I told him he had missed the opportunity – he should have kissed the frog in order to turn him back into a handsome Prince.)
Olwen Williams email@example.com