October 2021 Sightings

Ionathan reports a Heron trying to eat a large, adult Eel, on the bank of the Cam near the Boathouses.  Bob reminisces that in his young teens, the stream that ran through what is now the Science Park used to teem with Elvers. There were so many, they formed a dense thick rope making their way downstream into the Cam. He remembers catching a mass in a Kilner jar and surprising his mother with the squirming mass, whereupon she fled in horror!  Sadly this local eel reproduction no longer occurs.

Early in the month, Val noticed Bats flying in Edward St and Dorothea’s Hedgehogs are still up and about, happy in the mild weather it seems and eating well. Pat reports sightings of Water Vole in Jesus Ditch – they seem to be spreading well in the upper Cam now.  Ionathan saw some Ferrets with ‘masks’ over their eyes and asks if there are feral ferrets in Cambridge? Anyone else seen these?

While small birds are noticeable by their absence, there have been some spectacular mass gatherings. Newnham’s Corvid roost has built up to about 200 birds – a mixed flock of Jackdaws and Rooks. Val also comments on, “The most remarkable din from dozens of Rooks/Crows (with the odd Magpie interloper) all sitting on the roofline of the buildings on the south side of Burleigh St. The Seagulls looked completely discombobulated.” Jill reports immense Starling murmurations over the lake at Bolton’s Pit (off Barton Rd) – several thousand birds, settling on the island at dusk.  https://mail.google.com/mail/u/0?ui=2&ik=df44efff8d&attid=0.1&permmsgid=msg-f:1714978858259013058&th=17ccd42f6bd55dc2&view=att&disp=safe Video by Lynn Hieatt

Ionathan makes the case for more Oak trees!  He spotted a Nuthatch in Eddington (where there are many oaks) and another one in an old oak tree in Arbury. Bob comments that they are known to breed in Girton College where there are mature oaks. (If anyone can offer a home to an oak tree, please let me know, as I still have a few young trees.)  Jesus college turned up a Treecreeper (Rhona).

Lots of birds move about in the autumn and Val heard (and then saw) two Swans flying at a height going NW to SE, but nowhere near the river. Assuming they were Mute Swans, perhaps a young couple looking for an unoccupied site to breed next year?  Alec saw an unknown bird in Petersfield cemetery: his excellent written description “Bird. blackbird size +, white base of its tail. beige grey body, green flashes by wings near tail. Very fearless.” tracked it down to a Jay. Holly comments on a number of Jays caching nuts – this is the time of year to see them.

Cormorants Jenny Bastable

Kingfishers were noted by Burnside allotments (Holly, Monica) and a pair of Grey Wagtails on around the weir at Jesus Lock (Pat). Jenny was surprised to see Cormorants on Grantchester Meadows. These inland Cormorants are now well established in Cambridge – disliked by fishermen!

Although Harlequins Ladybirds were slow to appear this year, there were several end of season reports. The tombstones in Haslingfield (out of our area) were dotted with them, in their various outfits, suggesting a mass hatch had taken place there. Monica found one indoors, looking to hibernate. 

Paul (exotic as ever) found the larval case of one of the Case-bearing Moths on a Birch tree, possibly the Pistol Case-bearer (Coleophora anatipennella) or Birch Case-bearer (C.  betulella). These ‘Pistol Case-bearers’ are so named from the resemblance of their larval cases to an old flintlock pistol.  Rhona (equally exotic) found a Luffia species of bagworm/case-bearing moth on a wooden seat. There seem to be lots of different species of these micro-moths. A Jesus student found about 30 hibernating butterflies in the top of the tower (Peacocks and Small Tortoiseshells) – every species needs a strategy to survive the harsher weather.

Araneus diadematus, after laying eggs Rhona Watson

Rhona sent a picture of an exhausted looking spider! Pregnant female Garden Spiders Araneus diadematus are particularly noticeable because of their large body, swollen with eggs. However this one was thought to have laid her eggs and, job done, would soon die. Eventually the spiderlings will hatch in the following May. It is an unusual reddish colour, but there can be considerable variation in this genus. The related A. quatratus can actively change colour, taking about three days to take on colours that accurately match their resting surface.

A couple of interesting Beetles: Rhona reports a Pleasing Fungus Beetles (Erotylidae) in the Triplax genus. I was interested to know in what way it was “Pleasing”, but the nearest I came was the comment, “Most Pleasing Fungus Beetles are inoffensive animals of little significance to humans”.  Then Liza produced “The most stunning royal-blue beetle which turns out to be a Blue Mint Beetle (Chrysolina coerulans)”. It came to this country in 2011 and was found on Apple Mint, at Empty Common allotments.

A good selection of Fungi was found on the CNHS outings – see the CNHS web page for the Trumpington Meadows account. Notable were several species of Waxcap including Blackening Waxcap, also a good array of Shaggy Inkcaps (Mo). The Botanic Garden had the usual suspects, including Bird’s Nest Fungus under the new raised walkway, Birch Polypore on Birch logs, Magpie Mushroom and Plantpot Dapperling. Finds new to the garden were Parrot Waxcap and a Bolete growing under Oak, which therefore had to be Xerocomus cisalpinus (Jonathan).

As leaves fall from the trees, Rhona contributed these Oak Galls. What sort of a winter will we have, I wonder?

Olwen Williams olwenw@gmail.com