Gloucestershire Naturalists' Society

Ashleworth Constant Effort Site Log for 2 May 2004 - Mervyn Greening

The 05.00 meet at the end of dirty lane necessitated an alarm call at 04.30. Mad or what? Too early for breakfast so a quick drink, and the 15 minute drive. A few blackbirds singing as I left the house and the usual few birds sleepily finding their breakfast along the roadside. Anger and frustration on arrival to find that some moron had dumped a caravan then burned it in the gateway to the reserve. This wanton vandalism not only aesthetically unpleasant, but has also damaged the fine old oak at the gateway and the surrounding bushes. Nature is far more forgiving than me, and it was business as usual for the Robins nest building amongst the devastation. Thankfully the newly erected gate had prevented the caravan from going further into the trees, or more damage may have been done.

The yomp across the fields to the ringing site revealed that the Sedge warblers had arrived back in force, with fully vocal males singing at intervals all across the reserve. So loud were the Sedge warblers that it was almost possible to miss the willow warblers tumbling out their notes, and even the Robins were being deafened. Not so the Song thrush that was belting out it’s song, at points seemingly mimicking parts of a nightingale song, however the most impressive mimic was the Sedge warbler that incorporated some blue tit alarm call into it’s song. The recent rain had helped keep the water levels up and the rapidly growing grass and sedges were dripping wet. A heavy grey sky with no breeze at all, gave a sombre feel, enlivened by the bubbling of the curlew from across the ham.

The nets were quickly erected, and the routine of checking, extracting and processing soon underway. We take a table and chairs to form a base from which we carry out our operations, and it is to this we return after each walk around the nets. The repeated walks around a site during the morning, allows you to see the same place indifferent lights and moods, no two rounds are the same. The catch today was typical for the time of year, and comparison with previous years’ first visits is made in the table below. 32 birds of eleven species caught with just under 50% being Sedge warblers.

The attraction of this type of birding becomes apparent as birds become individuals. Sedge warbler P790658 was originally caught on the 3rd June 2002, an adult in breeding condition, she had already done the journey to sub-Saharan Africa at least once. That day in June she had a vascularised brood patch , indicating she had a clutch of eggs that she was incubating. By the 29th June, she had finished brooding and the patch was regressing. When caught on the 14th July she had put on weight, and with the heavily worn feathers, characteristic of adult Acrocephalus warblers,(movement through grasses and sedges is highly erosive of the feather surface) was getting ready to leave the breeding site, indeed, we did not see her again in 2002. She was only caught once in 2003, on the 7th June, again in breeding condition with a fully vascularised brood patch. Now at the start of the 2004 breeding season, she has arrived back, in exactly the same site she first occupied,(has always been caught in net 4) not yet in breeding condition, her under parts are still feathered over. Without the identity bracelet, and regular monitoring, we would not know the detail of this history, nor less marvel, at this 10g wonder, flying to Africa and back at least three times. All the more amazing is the fact that adult Sedge warblers don’t moult in this country, so she has done the journeys south with heavily worn feathers following her breeding attempts.

Sedge warbler p790658

Four more Sedge warblers were caught that had been ringed the previous year, three had been ringed as adults. However, one was unusual in that it was a bird ringed last year as a juvenile, and has not only returned to Ashleworth, but to the same breeding site. (Juveniles usually disperse away from the natal site to avoid competition with parents, obviously this individual was illiterate, or just decided to ignore the wisdom of our textbooks) One other Sedge warbler with a ring on was of interest, this because the ring in question was not one of mine! In ringing parlance a “control”, a bird ringed elsewhere, and whose movement can now be plotted by reference to the original ringing details; more of this bird and other controls at a future date. These insights and the close contact with the birds are what make ringing so compulsive for me.

The humid cool misty conditions were probably responsible for the Garden warbler caught on the first round. An unusual bird for this site, only three caught previously (2 in 2002 and 1 in 2003), this bird had plenty of fat for fuel, and had probably grounded because of the poor weather conditions during the night. The same weather also caused the spectacle of low level hawking by the numerous Swallows passing through. At just above grass height these fantastic flyers had to rise up over us or dodge round us as we made our way more laboriously through the vegetation.

The Garden warbler R561427

Skylarks had a “lie in” and were not singing until 08.30. The conditions probably weren’t responsible for the female Whitethroat in breeding condition caught in round 3. This is the second year Whitethroats have bred on the site. A male was heard later, singing from a perch, then in flight above a shrub, not far from the net where the female was caught. All morning, at least one Cuckoo was being heard, then we were rewarded with a hawk like flypast. One of the rounds had its peace shattered by the arrival and slow fly past of a flock of Black headed gulls. At about 400 feet above us they circled and slowly moved north, all the time raucously calling. Were they arguing, keeping contact, or sharing information? Whatever the reason, it’s equally puzzling what this group were doing here, not normally seen at this time of year, they ought to have been on their breeding sites. I assume that the Reed buntings have all settled down, having established territories, as they were very quiet today, with only one male breaking their silence with his simple song.

Reed Bunting R561435

A few ducks were around, the most noticeable being a flock of 7 noisy Shelduck, which circled the reserve a few times. A bigger flock contained a couple of Gadwall and Teal, as well as Mallard. Spring male Redstarts are one of the great joys of Ashleworth, and a bold male standing out at the end of a willow branch, singing at us as we walked past, was much appreciated. He and his mate will probably use a cavity in the old pollarded willow, from which he was singing, in which to nest. The old pollards are a feature of the reserve, carefully managed to conserve their value as homes for other organisms.

The bird activity fell off around 09.30, and coincided with an improvement in the weather. It’s always time to pack up when you see butterflies, and the arrival of Orange tips moving around the “Jack by the hedge”, and a Brimstone investigating the nettles, were as good as a clock to signify the end of another visit. Back at the cars, the Robins were still carrying mouthfuls of dried grass to their nest, the male even managed a blast of song with his mouth full! What an industrious bird, helping with the nest and proclaiming territory.

For the statistically minded, a few figures of first visit catches of the CES season at Ashleworth.

1999 and 2002 were the years with the two biggest catches, I wonder if 2004 will be similar?

An introduction to the Ashleworth ringing programme can be found here.

The first of Mervyn's reports covering the first visit on 18th April 2004 can be found here.

The report covering the visit on 2nd May 2004 can be found here.

The report covering the visit on 9th May 2004 can be found here.

The report covering the visit on 23rd May 2004 can be found here.

The report covering the visit on 4th June 2004 can be found here.

The report covering the visit on 13th June 2004 can be found here.

The report covering the visit on 26th June 2004 can be found here.

The report covering the visits during July 2004 can be found here.

The report covering the visits on 5th August 2004 can be found here.

The report covering the visits on 15th August 2004 can be found here.

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