Category: Science

UPDATE: Sunny Sunday, so went to take some brighter photos, thankfully he was still there and calling loudly.

Over the last few weeks, the flooded fields around our village of Cottenham have brought in quite a few interesting birds we’d not commonly see here, although some are more frequent visitors than others.

We’ve had hundreds of Whooper Swans and a couple of Bewick’s Swans (for the first time in recent years), Red Shank, Oystercatcher*, Little Ringed Plover, Grey Plover, Golden Plover*, Green Plover* (Lapwing/Peewit), Shoveller Duck, Shelduck, Wigeon, Green Sandpiper*, Kumlein’s Gull, Avocet, Dunlin, Black-tailed Godwit, Snipe, Grey Wagtail*, Yellow Wagtail, White Wagtail, Pied Wagtail*, and various others. *Seen more than the others listed. Hen Harrier, Peregrine falcon, and Marsh Harrier have also been spotted, as has (away from our patch) White-tailed Eagle.

Today, well away from the flooded fields, a Nuthatch turned up at All Saints Church and was singly loudly variously from the yew tree at the main entrance, the trees at the vicarage, and the tall, budding oak behind the church.

As far as I am aware, this is the first sighting of a nuthatch in Cottenham for many, many years. Unless you know different, of course.

Thanks to Simon G, Brendan D, and Ian E who are the proper birders who first ticked and counted the various birds listed above.

Song frequency sits mainly between about 2.8 and 4 kHz, another bird calling at 7kHz towards the end of the video. A high-pass filter applied at about 1.3 kHz to mute wind and traffic noise.

The frozen circle of a Whooper’s life

Video by Grant Norman

Words, narration, and incidental music by David Bradley

Each winter, they arrive in their thousands. White, winter visitors flying in from the frozen north. Most will have come from their breeding grounds in Iceland. They navigation the east coast and sight land in North Norfolk. They will keep flying to their usual splashing grounds at Welney. The Whooper Swan.

The vast squadrons roost overnight on the waters, safe from foxes and other landlocked predators. When dawn breaks, they head for the fields. Where they will hoover up the green-top residues of beet and potato harvests. Before returning to their watery roosts each dusk.

In late 2020, the farmland around Welney and the Ouse Washes were floodier and floodier. The Whoopers were compelled to spread their wings and search farther afield. However, by January almost as soon as Fen Bridge Farm had harvested their sugarbeet. Several dozen arrived. The numbers have grown and grown.

Everyone in the village is asking everyone else about the honking and whooping. Is it geese? What are those birds? It’s amazing to see when you catch sight of them from the Lode or Les King Wood. By the end of January, almost 500 were on the flooded field there. Most of the greentops seem to have been purged from the land.They will most likely soon move on…to “pastures” new, although it’s worth noting that some are not even flying to roost these last two or three evenings, preferring to stay on the flooded farm at the edge of Cottenham.

We will have to wait and see whether they return to our Fen Edge Patch next winter. It will all depend on the flooding and the farming. Before the spring arrives though, this year’s birds will depart. Heading back to the frozen north for the next round in the circle of a Whooper’s life.

UPDATE: Numbers have been falling over the last few days. There were only four Whoopers on the frozen flood patch at the farm when we walked past today. They bobbed their heads and took flight as we walked past. Be interesting to know whether that’s the end of them on our fen edge patch for this year. It could well be…

TL:DR – We had a large influx of Whooper Swans on the outskirts of Cottenham early in 2021. The spectacle has not been repeated since but there are numerous birds of that species farther afield and several Bewick’s Swans sighted.

UPDATE: January 2022 – Several hundred Whoopers arrived on Bullock’s Haste and out on Setchel Fen. I should add that fellow villager Ian Ellis undertook a detailed study of bird species on the flood at Smithy Fen and recorded well over 150 different species. Many of the species he recorded are not commonly seen in these parts.

December 2021 – WWT Welney wardens counting well over 13000 roosting Whoopers on their patch.

Back in November 2020, I noticed quite a lot of swans, Whooper Swans to be precise, pecking and calling on the farmland between the River Great Ouse and the fenland north of our village, Cottenham. Those numbers have gone up substantially in the last week or so. (Update: 2021-01-31 – 500 swans)

One birding friend Ian counted 500+ on a trek along one of the droves to observe them, and he reported back again today that he estimates there are perhaps 800 spread across two or three sites north of our village. Moreover, reports from elsewhere around Cambridge hint at four-figure numbers of the birds on our patch, he says.

Another friend, Chris pointed out that he was being kept awake by honking calls from behind the Tenison Manor Estate, locally referred to as “The Birds” because the street names are bird names. Turns out it’s Whooper Swans (Cygnus cygnus) there too, between the Cottenham Lode, The Cut, and the Les King Wood, perhaps fifty or so. The numbers may swell as the winter moves on.

If you’ve ever visited WWT Welney* in Norfolk, you may well be familiar with the Whooper Swan. They’re a big white bird, with a black and yellow bill, but they lack the bobble on the bill of the more frequently seen Mute Swan (Cygnus olor). The Whoopers head south from their summer breeding grounds in Iceland to find food and shelter. Welney welcomes thousands of winter visitors, including Whoopers and their relative Bewick’s Swan (Cygnus columbianus bewickii) each winter. Apparently, this season, there is so much flooding and food on farmland, that very few swans are showing at feeding time at Welney. The “w” is silent in whooper by the way, viz whooping cough, so it’s pronounced “hooper”, in case you were wondering. It’s not silent in WWT Welney.

Regardless of which field you spot the Whoopers on, they fly to roost each evening. They head north to open water, the washes, for instance, possibly even Welney itself, Ian tells me.

You might also notice that scientific name, the binomial, of the Whooper – Cygnus cygnus. This is another tautonym, the repetition of the genus in the specific (species) name indicates that the Whoopers are the  “type” of the swan genus, the archetypal swan, just as Buteo buteo, the Common Buzzard, is the archetypal buzzard and Gorilla gorilla gorilla, the Western Lowland Gorilla is the archetypal gorilla.

There are lots of flooded fields around us that have also attracted Teal, Gadwall, Pochard, Wigeon, Goosander, Shoveller Ducks, and others, birds that we do not commonly see on the farmland around our village. Other birds to watch out for feeding in the fields and hedgerows – the winter thrushes: Fieldfare and Redwing. You will also see Corn Bunting and Reed Bunting, Yellowhammer, and Meadow Pipit. These are here all year. So too, Linnet, Goldfinch, and Greenfinch which are flocking around the outskirts of the village groups of several dozen depending on where you go for your allowed daily exercise.

Also to be seen: male and female Stonechat (usually in pairs). You might also see small gatherings of Pied Wagtails around farmland wet patches and on dung heaps. You might even spot the yellow rump of its relative the Grey Wagtail, but you most likely won’t see a Yellow Wagtail just yet, they’re summer visitors. But, do keep your eyes peeled for the European relative of the Pied Wagtail, the White Wagtail, which seems to be turning up more frequently now. At the time of writing, Water Pipit were not on the village list, but birders have seen them since.

Also, given the flooding and the growing number of Glossy Ibis around Cambridgeshire at the moment, it would great news to hear of one on the Fen Edge Patch, do let me know if you see this rather exotic visitor within walking distance.

Having bumped into friends while owl spotting in the fens, we pointed out a male Little Owl on a woodpile at Priory Farm near Burwell. After our friends had moved on, however, Mrs Sciencebase spotted a second owl (a female). The female is in the darker photo, on the higher perch (a bigger bird than the male as is usual with owls and raptors).

We didn’t see any Short-eared Owls on NT Burwell Fen nor Tubney Fen today, unfortunately, although one or two have been seen this winter there hunting in the early afternoon as opposed to the more likely hour or two before sunset.

There are it seems half a dozen Shorties hunting at Great Fen in Huntingdonshire. Interestingly, there are theories about the lack of Shorties when that happens. One suggests that the birds only head south from Scandinavia if the lemming populations up there are low. However, the half a dozen in Huntingdonshire suggests that more likely is that the presence of the Konik ponies on Burwell Fen over the summer has left the scrub grazed too heavily giving the owls no choice but to find an area with longer scrub in which to roost. Add to that the lack of hunting Kestrels there recently which suggests that the vole population has pulled back its breeding to reduce predation this summer, something that prey species are known to do as it then temporarily reduces breeding success of the predators giving the prey species a better chance in the next season. This seems to happen on a three-year cycle.

We headed back to NT Wicken Fen visitor centre having been tipped off to a sunset roost of Hen Harriers (a couple of proper birders confirmed that some of the harriers we were watching were three male Hen Harriers quite a significant time before sunset, there were also several Marsh Harriers, and a couple of Barn Owls hunting over the reeds.

UPDATE: Thursday, 7th Jan 2020, on a walk, we inadvertently flushed a Short-eared Owl from its scrubby roost in the nature reserve behind a research park north of Cambridge. It flew into an adjacent field to watch us for a few minutes before taking flight.

BIRD REPORT 13 – Glossing over any egrets

This post is an online version of my latest nature column, which I volunteered to write regularly for our bimonthly, printed village newsletter. the Xmas issue has an article about local starling murmurations, report 13 is for the next issue.

In the last Bird Report, I mentioned sightings around our local patch of some quite unusual birds, birds that are normally associated with sub-Saharan Africa, or at least the much warmer parts of Europe. There were two glossy ibis at RSPB Ouse Fen in November. Subsequently, there were sightings of more at RSPB Fen Drayton and close to Earith Sluice. It is likely there are about seven not too far from us.

I also mentioned Cattle Egrets in the last issue of which there were five or so on farmland on the edge of Fen Drayton and sometimes some seen in the nearby RSPB reserve roosting alongside the cormorants beneath skies filled with the shadowy forms of the starling murmurations. Now, many readers will know the little egret, the grey heron and perhaps the bittern, but the cattle egret is a less well-known member of the family.

When I moved to Cambridge a little over thirty years ago, it seemed rare to spot a little egret, although grey herons definitely frequented the banks of The Cam not far from where I lived. Seeing a little egret on the Norfolk coast was an occasional treat, but now their numbers are up greatly, it seems. I’ve counted 30 or so at a time in fields at the edge of the Fen Drayton reserve. Also on the rise are great white egret numbers. They seemed to be a true rarity until very recently, now even the most novice birder will have “ticked” them several times on local reserves and I’ve seen them on several occasions feeding on the Cottenham Lode alongside grey heron and little egret. Those cattle egrets too, once a very rare sight, are seen more and more, with handfuls, trailing after any cattle they can find in our locale. On the Somerset Levels they are now reported in their hundreds.

Climate change is no doubt playing a part in allowing these species to spread farther and farther north into the British Isles from their erstwhile homes in sub-Saharan Africa, to North Africa, The Mediterranean and beyond. The glossy ibis is found scattered around the warm regions of Europe, Asia, Africa, Australia, and the Caribbean, for instance, but birds that are breeding in southern Spain seem to opt to spend the winter in The British Isles over the last decade or so. But there seems to be another force driving these egrets and other wading birds. The non-native and very edible red swamp crayfish has in recent years thrived in the lakes of northern France, for instance.

I say edible, this delicacy known stateside as the Louisiana crawfish or crawdaddy, is a native to northern Mexico and the southern USA, but has been introduced to Asia and Europe and has established itself invasively in southern Europe and more recently spread to those French lakes. This has apparently given the birds that enjoy a few crawdad themselves a stronger foothold further north. It was perhaps inevitable that those species would find ways to extend their range and feed on the native aquatic species found in our coastal, brackish, and inland water, especially the species with a migratory tendency. If the red swamp crayfish gains a clawhold in those waters, it will be bad news for some of our native species, such as the European crayfish, but good news for the feathered fishers.

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Spottin’em in Cottenham: Recent sightings

Some interesting recent activity in and around Cottenham. One cold and foggy November night, wigeon were reported flying over the High Street and a Sunday morning soon after saw a couple of Egyptian geese over Broad Lane, a first sighting for one reader of that non-indigenous, but widespread, bird in Cottenham.

There have been a couple of waders, green sandpipers, specifically, sighted along Long Drove, they’re not uncommon in the fens, but always nice to see. Also, at the time of writing, around 60 whooper swans were on farmland at the Twentypence Marina end of the Cottenham Lode where it drains into the River Great Ouse, sometimes known as the Old Bedford River.

Also, way off its normal patch, a dusky warbler has been seen in Aldreth at the part of the village known as The Boot. A white stork (possibly an escapee from a collection) has been seen in Somersham.