Author: David Bradley

Early evening walk (31st May 2017, farmland south of Rampton, Cambridge, relatively close to the Guided Busway), hoping to catch sight of our local fen edge barn owl (Tyto alba), but could hear a cuckoo (Cuculus canorus) in a field beyond a hedgerow…call seemed to be getting closer…at which point two males flew over our heads calling, each presumably attempting to out court any nearby females. Female song is very different from that of the male and not heard so often. I got a quick shot of one of the two as they passed overhead calling all the while and they separated in their ongoing search for cuckoo nookie.

The male’s call is familiar to many people even if they have never seen this thrush-sized bird that resembles a small bird of prey, but is neither thrush nor raptor.

I suppose it was obvious in hindsight, it was RSPB Fen Drayton Lakes, there were reeds, there was warbling, it was a reed warbler (Acrocephalus scirpaceus). Despite his whitethroat and white rings around the eyes, he’s simply not a whitethroat (Sylvia communis). He wasn’t singing the whitethroat tune either.

Bird expert and friend Brian Stone explains: “Subtle but distinctive, the head shape is typical of the Acrocephalus warblers. Rather pointy with a steep forehead. That genus also tends to be very uniform in colour and many species are extremely difficult to separate if not singing. Fortunately we only have two really common species here and sedge warbler looks rather different.

Indeed, I had seen and identified positively sedge warbler recently at RSBP North Warren on the outskirts of Aldeburgh, north on the way to Thorpeness, and had seen said sedge warbler again not a few paces from the reed warbler.  Brian tells me: “Much more streaky and with a very bold face pattern. Reed Warbler goes much more for the no-nonsense brown on top, pale buff underneath approach.”

To me, it will always be Swavesey Lakes, but when the RSPB took on the old gravel pits that lie north of Fen Drayton, south of Holywell and west of Swavesey, they deemed a name change was in order, as I understand it.

The lakes, riverside, traditional meadows and hedges are linked by a network of paths and alongside is the Great River Ouse, which begins in Syresham in South Notts winds its way through East Anglia to The Wash. It’s a lovely site, you’ll see vast starling murmations at dusk in the early autumn, but at this time of year it’s a flutter of activity from countless feathered friends.

We parked up at about 10 on the late May Bank Holiday Monday in 2017, and could immediately hear willow warbler, chiffchaff, great tit and a couple of distant cuckoo.

Overhead what I thought was probably a marsh harrier or two, but actually realise now they were red kite. On the “board” promise of a bittern and oystercatchers with young. We saw a colony of greylag geese with goslings on the opposite bank of the River Great Ouse, but no other obvious bird young. The greylag’s had neighbours too: Egyptian geese.

On the pontoons that festoon some of the lakes there were plenty of black-headed gulls nesting and some common tern. On the outcrops into the lakes and the water’s edges: mallard, tufted duck, lapwing, mute swan, great crested grebe, redshank, cormorant, pochard, grey heron, and various others.

In and around the trees: blackcap, sedge warbler, long-tailed tit, robin, blackbird, wood pigeon, chaffinch, chiffchaff, goldfinch, collared dove. And, among the reeds, reed bunting, whitethroat, and reed warbler too. And a pair of nuthatch, based on a fleeting glimpse of two small birds with blue-grey colouring and rusty flanks and a monotonic and repetitive whistling.

Overhead Canada and greylag geese, mute swans, housemartins, barn swallows, and others.

Having heard the cuckoo there was always the hope of spotting one of these rapteurish-looking parasites, but we were not in luck.

I was also hoping to catch a shot at a yaffle or two (green woodpecker, in French: Picvert, “green pick”). As we drove off the site, there were lots of LBJs and we almost ran over a yaffle, which took to the air just in time. The female partridge on the opposite side of the road barely flinched and the female yellowhammer just flew.

I should point out that we were there in the middle of the day, a dawn or dusk visit would be much more fulfilling given the dawn chorus or the twilight hunters and the birds coming home to roost, respectively.

 

Walking the dog at dusk out on the Cambridgeshire fens mid-May, lots of swallows around, meadow pipits, yellowhammers, the inevitable wood pigeons, collared doves, starlings and blackbirds, a few LBJs (little brown jobs), chaffinch, house martins, robins, (barely glimpsed, but certain) goldcrests and more. Heading along the lode thought I saw a little egret out of the corner of my eye, but turned to see a beautiful barn owl (Tyto alba) in the lowering sun circle the fields, hunting small mammals, worrying the skylarks on their nests.

The shot above was the first I captured, it’s often the way, first shot on the reel is the best, the most spontaneous, the one that’s just right, the subsequent photos are as the owl passes by and so mostly rear-end shots. He did bank around again and fly towards us a couple of times, taking no heed of our presence nor of the dog, and not even the sound of the camera’s shutter distracted from his time to pray. Here he is being defined in his nomenclature by the that most obvious of farm buildings, a barn.

He circled back around of the field on our side of the lode and we watched as he dived down, emerging from the long grass a few seconds later with a shrew in his talons before heading off in the direction of a patch of woodland (ironically close to where we’d parked the car).

It must be ten years since I last got a photograph of a barn owl. We’ve seen a few and certainly enjoyed watching one range alongside the car in the Yorkshire Wolds a couple of years ago, presumably hoping our wheels would disturb the roadside mammalia into scurrying.

Barn owls are well known as silent fliers. Their wings are huge compared to their body size and mass, they are also curved. Both characteristics are evolutionary adaptations to their hunting technique. They can move very slowly with barely a flap even in the lightest of updrafts almost hovering over prey they have sighted. But, it is the structure of the feathers which makes them much quieter than other raptors allowing them to hear prey without the background noise of their own wings.

The barn owl’s wing feathers are soft which smooths airflow, reducing noisy turbulence. In addition, the leading edge of their foremost wing feather (the 10th primary) is fluted appearing to have tiny barbs (that have tiny barbs upon them) that break up the airflow hitting the wing and again reduce noisy turbulence.

It might be that the flutings raise the frequency (pitch) of the sound above that audible to prey and perhaps the owl too. Indeed, the owl’s silence does mean that it can hear its prey in the groundcover whereas other noisier raptors need to rely almost entirely on their sight (viz, the kestrel hovering high above likely targets).

Nice BBC program showing pigeon, peregrine, and barn owl in flight. The sounds they do or don’t make and the turbulence their wings do or don’t generate. It’s worth noting that pigeon wing flaps are thought to be a communication device too. Peregrines stoop on their prey so quickly and aren’t flapping when they do so any noise the make in normal flight doesn’t matter. Also, Barn Owls keep quiet not so that their prey don’t hear them, but so that they can hear their prey and home in on the tiniest rustle of blades of grass or the twitching of a rodent whisker.