Monday, 19 October 2015

Red Letter Day

For the last couple days the winds has been coming in from the East, sending birders scurrying to the coast in search of rare and vagrant birds brought over from the continent. Red-flanked blue tail, yellow-browed warblers, Isabelline shrike and Pallas’ warbler all turning up at coastal sites around Norfolk and Suffolk. To me, yes these are exciting birds, some of which I would love to see. But my priorities have changed. And it is not all down to the little Robyn bird that has become the centre of my world over the last 12 weeks. Even before she arrived, once I had become a bird ringer my priorities and focus shifted from birding to bird ringing. The easterly winds may have brought some unusual birds but it also heralded the return of our common winter migrants. Across the dark velvety sky in the early hours of Wednesday morning, with stars still twinkling and only the smallest hint of lightening of the sky signally the coming dawn, came the distinct but thin, almost wistful ‘seep’ call of one of our commonest winter migrants, but also one of the most beautiful. 

In the gathering light, with the reeds and trees at Cranwich rustling quietly in the breeze, we set a series of mist nets. Through the dark comes the deep rumbling roar of Red Deer, hidden by darkness and trees but sending tremors through the early dawn. As the morning draws on the sky is soon filled with hundreds of small, dark thrushes, with that distinct ‘seep’ call. They are Redwing. Circling through the sky now filled with hurrying clouds, moving in flocks from one tree to another and soon dropping down to where our nets stretched through open corridors between the pools, reeds and trees. 

The beautiful Redwing

Up close they are beautiful birds. A bold, creamy stripe above the eye, cuts through the olivey brown feathers of the head. A slightly less pronounced stripe runs underneath the eye. The glossy brown continues down the back and tail, while underneath the pale chest is streaked with dark brown spots. Under the wing is a deep, chestnut-red splash of colour that spills onto the flank and from which the bird gets its name. 

For each bird we look to age it by assessing the quality of the feathers, looking for any changes in colour, any pale fringing and the amount of wear. From this we can tell whether the bird hatched this year, or either the year before or at some point before. Due to the way adult passerines moult after each breeding cycle we have no way of knowing exactly how old the bird is from feathers alone. Only ringing details can do that. Once aged, we measure its wing, record how much fat it has, the condition of its breast muscle, and weigh it. It is then released to join the rest of the flock still hanging round the willows and alders of Cranwich. 

It is a tremendous day, with so many Redwings moving through we inevitably managed to catch a few…. Well 66 to be exact! But that was not all for the day, Goldcrest, Treecreeper, Robin, Chaffinch, Chiff chaff, Wren, Greenfinch, Reed Bunting Long-tailed Tit, Cetti’s Warbler, Kingfisher, Siskin, Lesser Redpoll, Song Thrush, Marsh Tit, Great Tit, Blue Tit and even a Willow Tit (a species that until this year we have not caught on the site since 2009!) added to a the grand total of 195 birds caught and processed on this Red Letter Day for ringing at Cranwich. 

Willow tit 
Cetti's Warbler

Friday, 9 October 2015

Bearded Beauties

Head to many of the larger reed bed sites in Norfolk and Suffolk and you have a good chance of encountering these little birds. In many cases you may not even see them. From the tall, waving reeds their nasal ‘ping’ bounces around like a pinball machine. If you do see one, it is often a small, seemingly brown ball of feathers, trailing a long tail zipping across the tops of the reeds. If you are lucky enough to catch site of one stationary you are confronted with a small, beautifully marked and delightful little reedling that is at home gripping on to a vertical reed stem. The brown is revealed as a tawny, orangey brown and there are stripes of creamy white and black on the wings, a long rufous brown tail trailing behind the stocky little body. The males have a silvery blue grey head, small bright yellow bill, brilliant orange eye and stunning black moustaches... so I guess Moustached Tit did not have quite the same ring as Bearded Tit. The females, while lacking the silvery grey head and moustache, are still just as delightful but in a more subtle way. 

So yes, while throughout the year you may be lucky enough to hear or even see these little, restless birds in the larger reed beds of the region. But at our comparatively little reed bed at Cranwich? Well as a matter of fact yes! In the past few years the characteristic pinging of a pair of Bearded Tit has been heard in the reeds fringing the margins of our pools. Clearly while many Bearded Tits remain in their large reed beds year round, some disperse during the winter. The calls at Cranwich have only been heard in the autumn and spring, there is no sign of them breeding… yet.

So with the final session of the season underway it is with some excitement that through the still, cool autumnal early morning we hear that pinball ping. With the sun beginning to warm the cool air it was with delighted surprise that from the bird bag I took out a stunning, male Bearded Tit. The first time I had held this gorgeous bird in my hand. The next net round brought the added pleasure of catching a female. 

A stunning male Bearded Tit

No less beautiful, the female Bearded Tit

So here we are, on our little reed bed site with a pristine pair of Bearded Tits. Both adult and young of the year replace all their feathers at the end of summer, so there is no way of telling whether these were young dispersing or adults moving away from the breeding sites. Where did they come from? In all likelihood to answer is nearby Lakenheath but may be somewhere further afield? But where do they go to? Remain at Cranwich for the winter or carry on to some other destination? And where will they return to breed? One day could the answer to that be Cranwich? Ringing this pair will hopefully help to start providing some answers…

Monday, 5 October 2015

Snakes in the grass

Along the grassy margins of the pools, nestled amongst the tall grass, reeds, alders and willows at the waters edge, and near to the open spaces of short grass and sandy soil at Cranwich there are a number of dark, corrugated sheets. The warm sunshine of a sunny September beats down on the black material, warming the soil beneath. It had been a cool night and the surrounding grass, reeds and leaves were damp, water droplets glistening in the bright sunlight. It was with great care that we approached these corrugated sheets, gently lifting them to discover the secrets hidden in the warm, darkness. As the light flushes the area, a quick movement catches the eye, and it requires even quicker reactions to catch it’s source. Lifting the beautiful animal into the light the sun glistens off dark, brownish grey scales that when catching the light look almost bronze. Its belly is pale yellow. Down its side and especially underneath there are jet black scales forming a pattern that is distinctive to each individual. The head has a bright yellow and black collar, and a gleaming eye with round pupil. From the mouth a dark, forked tongue darts in and out tasting the air. It is a beautiful Grass Snake. It coils around the hand holding it, supple and sleek, there is nothing slimy about it, it is all muscle. The tongue continually tasting the surrounding air. 

A beautiful Grass Snake

Checking more refugia reveals more snakes, each a Grass Snake but each distinctively different. A different arrangement to the pattern of black scales, a different variation to the colour of the brown scales. One is much darker, another an almost olive brown colour. The largest is just over a metre in length, the smallest reaches from tip of finger to elbow, and is as thin as a pencil.

Checking more refugia

The habitat here is perfect for them, plenty of long grass close to water, providing a ready supply of amphibians, the snakes preferred prey. 

The series of refugia have been purposely placed around the site since the spring when the snakes would have come out of hibernation and sought out food and a mate. Throughout the summer a student has been monitoring the snakes catching, measuring and photographing them. Like with the bird population we want to know how many snakes are using the site, and like with birds we use the technique of ‘mark recapture’ to do this. However unlike with birds where we add a small metal ring with a unique number inscribed, with snakes it is simply a case of taking its picture. The unique pattern to the black markings on the belly of each snake will be more than enough to identify individuals, much like a human finger print.

Stunning markings on a Grass Snake

As the summer has waned into autumn, even with its final warm flourish, the number of snakes being found has begun to drop, as many start seeking out places to hibernate, a safe haven for the cold winter months ahead. For now with the warm autumnal sun beating down, it is time to release the snakes back into the long grass or the nearby water, ready to continue hunting before they too head for hibernation.