April Sightings 2020
This month’s specials!
Although (or possibly because) we are still in pandemic lock-down, I have had a huge response to my request for sightings again. Who needs walks into the countryside when so much turns up on your doorstep?! Highlights were reports of Grass Snakes (one at the Sanctuary Reserve (Paul), one in Paradise (Vic) and one swimming in the brook near the Burnside allotments (Holly)), a rare Snail and a Weasel.
In the spring warmth, bats are out of hibernation : Richard’s detector picked up six species flying around the house at Hobson’s Park: Pipistrelle, Soprano Pipistrelle, Nathusius’ Pipistrelle, Noctule, Lesser Noctule and Serotine. My sighting of the month was a couple of views of a Weasel playing around the hedge near Skaters’ Meadows. Jill reports Water Vole in Hobson’s Brook at Empty Common and also noted a Hare crossing Grantchester Road. Muntjac are ubiquitous as ever: one was spotted in a garden off Newmarket Road (Sarah). Rhona’s Jesus College Foxes are perhaps suffering marital discord with the lock-down. The Vixen was seen carrying cubs, (at least 4) one by one, across College and out along Jesus Lane and Manor Street. It seems she has taken them to a new den in Christ’s College gardens. Meanwhile, the Dog Fox is still seen in Jesus grounds most days. Vanessa sent a lovely video of a young Rabbit family in Hobson’s Park, greatly enhanced by the background of a Lark singing and a contribution from a Cuckoo.
Besides this Cuckoo heard in Hobson’s Park on 4th Apr, several others have been around this month. In Newnham, they were calling between Apr 28th to May 2nd (Jill, Penny, Olwen), in Highsett on 3rd May (Vicky), Cherry Hinton on several mornings (Holly) and in Trumpington Meadows on 19th April (Mo). Mo also spotted a migrating Wheatear in Trumpington Meadows on 22nd and Maria reports an Oystercatcher on the lake in Hobson Park – this is turning out to be a magnificent place for birds.
Barn Owls are back in Newnham, flying low over the meadows both morning and evening, in broad daylight (Sandie, Dorothea). Red Kites are becoming more regular (Vicky) and Martin noted numerous Buzzards over the city, including three above Fenner’s cricket ground recently.
Lots of folk mentioned their garden birds: using nest boxes, coming to feeders or just being around (Bernie, Jane, Loic, Maria, Jean, Holly). Thanks for all these. Bird song has been deafening this year, perhaps because of the lack of traffic noise. I found myself wondering whether they had increased their volume over the years and would sing more quietly if all the cars went for ever – sadly this hypothesis will not be tested. Val notes “The 8pm Thursday NHS clapping startles all the birds, who fly off in alarm”.
Spring migrants continue to arrive. Martin saw his first Swift on 28th April, earlier than usual. Common Terns have been seen in Newnham (Olwen) and Hobson’s Park (Richard). Swallows arrived by 9th April (Jeff) and on 29th a cloud of House Martins joined them over the Hobson’s Park lake feasting on insects (Richard). Reed Warblers were heard in Trumpington Meadows on 19th (Mo). Jeff reports Sedge Warblers (2 on 15th) by the Cam in Grantchester Meadows and 3 Whitethroat and a Lesser Whitethroat on 19th, all singing along Grantchester Road. There are large numbers of Chiffchaffs and Blackcaps almost everywhere and last year’s Cetti’s Warbler have returned to Cherry Hinton lakes (Holly).
What else?! Grey wagtails in Grantchester and Newnham, (Loic, David): a Nuthatch in a Newnham garden (David), Jackdaws sitting on the Cardoon seed heads, scavenging fluff for their nests (Jane), Reed Buntings in Trumpington Meadows (Mo), Tree Creeper in Byron’s Pool woods (Vanessa), Buzzards circling over the city (Jean), Peregrine on URC in the city (Vicky), a pair of Partridges exploring an abandoned building-site at Homerton College (Sam), a male Tawny Owl in Histon Road Cemetery (Lesley), Jays (Colin, Holly), Little Grebes nesting on Trumpington Meadows pond (Duncan) and Jeff’s list which included Marsh Harrier (1st summer female), Red Kite, Yellow Wagtail, Wheatear female in Grantchester Road. A spectacular haul.
I have been struck by the scarcity of Collared Doves and Jane also says theirs seem to have disappeared. Another non-sighting – a troubling lack of Moorhens on Jesus Green, where previously there used to routinely be ten or a dozen, but recently barely any (Lesley). Then a complaint from Richard! Canada Geese invaders are breeding at Hobson’s Park. I remember the Colleges had this problem on the Backs and invested in a mock Coyote – effective apparently.
So much for the birds – what about the bugs?
Maria send a pic of a Rosemary Beetle (Chrysolina americana). Originating from south Europe, it has become established in Britain since the late 1990s. Paul’s garden continues to produce an amazing array of invertebrates: first 14-spot Ladybird of the year and the bug Mocydia crocea. The harvestman Platybunus triangularis was in the Sanctuary Reserve and Shieldbugs Dock Bug, Hairy Shieldbug and Juniper Shieldbug all turned up in Trumpington (Mo).
Large Red Damselflies appeared through the month and Duncan has been waiting to see the first Hairy Hawker dragonfly. More and more butterfly reports (Brimstone (Alec), Speckled Wood (Karsten), Orange Tip (David), Red Admiral (Jeff), Holly Blue (Val)) – thanks to all who sent these.
Ben’s highlight for April was finding Hairy-footed Flower Bees in the garden. Bill’s experience was not so good – while some of his Honey Bees were flourishing, he had a nasty attack of Wax Moth (Galleria sp.) pupae in a bee hive. Pam has been carrying “Bee Saviour” Cards, with which she was able to rescue a damp and bedraggled Queen Bumble Bee. After probing the sweet spot, it warmed up, did a buzz and a short flight, then zoomed off! Wasps are also emerging: Paul snapped a Common Wasp queen, who after drinking in the pond flew to the greenhouse to preen herself and have her portrait taken. He also found Marsham’s Nomad Bee, a new species for his garden list. All nomad bees are wasp mimics and kleptoparasitic, entering the nests of a host and laying eggs there, stealing resources the host has collected. John asked about another “Bee”- actually a fly pretending to be a bee –the Bee Fly Bombylius major. Another parasite of bees and wasps, its eggs are laid in the nest and the larvae eat the host larvae.
Lesley sent a picture of my favourite snail, Cepaea nemoralis, the banded snail, This extremely variable snail is much studied by geneticists. The pattern of banding and the underlying colour are all quantifiable genetic characters. This one was “yellow” (there are also “pink” and “brown” ones) and of the potential 5 rows of bands, it seems to have 2 and would be scored as 1-0-3-0-0. Even better, this guy does not attack your plants, living mainly on detritus – so don’t squish him!
Paul also had a snail adventure. On Worts Causeway on the way up to the Roman Rd, he found several small (~15mm) snails. His initial identification was Kentish Snails Monacha cantina , but an expert identified it as the much smaller and far rarer species Monarcha cartusiana Cartusian Snail. (In 1999, this was only known from a total of fifteen 10-km grid squares in coastal areas of South Eastern England. It was probably introduced to Britain from Southern Europe as a “weed” of cultivation by prehistoric farmers (Susan Hewitt).)
We mustn’t let the animals have all the attention – the plant hunters have had fun too.
Paul found large clumps of White Ramping Fumitory in flower in Coleridge recreation ground, Chris noted a very pale Green alkanet Pentaglottis sempervirens on River Cam opposite Jesus Green. Jill came across a ditch full of Water Crowfoot behind the rugby club. Although recently dredged, this is stagnant water. Vanessa found Three-cornered Garlic, Allium triquetrum on the guided busway in Trumpington – an introduced plant from the W. Mediterranean.
More complaints from Richard! Hoary Cress or Curse-of-Kent Lepidium draba, an aggressively rhizomatous species thought to have been introduced to the British Isles with fodder or straw, is spreading ominously into Hobson Park. Green Alkanet Pentaglottis sempervirens is forming ‘extensive monocultures’ with a ‘strong negative impact on most of the native species’ that it replaces on banks and beneath hedges. A garden escape, comparatively rare as recently as the 1960s, it is now naturalised and spreading widely. I am certainly aware of this taking over my allotment and other places locally. Himalayan Balsam (Policeman’s Helmet) Impatiens glandulifera seedlings are emerging near the entrance to Byron’s Pool LNR. It forms high dense stands probably restricting the growth of native species. This has been fought by the Wildlife Trust up and down the region’s minor waterways and clearly the battle is not yet won.
On brighter notes, Jo found Nonea lutea, a rare weed, growing at Murray Edwards College, probably introduced with top soil. Simon likewise found Musk Storksbill Erodium moschatum, a long way from its designated habitat! Horse Chestnut ‘candles’ have been magnificent. I learned that the centre of each flower changes from yellow to red after it has been pollinated. Apparently all flowers will eventually turn red, but pollination speeds up that process by a day, giving a traffic light signal that directs pollinators to fresher, unpollinated flowers. (Thanks Paul). Cowslips have also been magnificent everywhere this year.
Last month’s mystery (above) was a Hoverfly pupa, Epistrophe eligans. Louise Bacon (the only contender!) came very close. This month’s puzzle picture was taken in Churchill College – below. Who will be the first this time?