Gloucestershire Naturalists' Society

Ashleworth Constant Effort Site Log for 23 May 2004 - Mervyn Greening

The high pressure area that settled over Britain this weekend gave a cloudless night, so it was beginning to get light even at 03.50 when I was awoken by our resident Blackbird. The drive over to Ashleworth for an 04.40 meet was notable for the number of Blackbirds, nearly all male, that were on the road, dicing with death, as I struggled for wakefulness. A fortnight since our last visit, and the season has moved on apace. The vegetation in the fields, still growing like mad, taller in places than the shortest member of our party, was soaking with dew. For those who scorn the use of waterproof over trousers, wellingtons provide scant protection, and the resultant soaked socks needed ringing out frequently during the morning. Putting up the nets was a chilling experience, with ice clinging to the poles, freezing our fingers. The compensation, however, was the spectacle of the sunrise. Ashleworth does sunrises on a grand scale. As the red orb climbs above the trees at the north-eastern end of the reserve, huge shadows spread across the grass, and a faint mist lifts, gently putting everything out of focus. Where else would you rather be at this time? Yellow flag Irises, picked out by the sun, are now splattered over the damper parts of the reserve, patches of vivid colour in the crazy paving of greens. And all the while you are serenaded by the dawn chorus. Paradise indeed.

A Sedge Warbler's view of the hide from the far field of the reserve

Despite the bright sun, which is not an aid to mist netting, we made a reasonable catch for the time of year. Thirty-six different birds were handled, of which 20, or 56%, were Sedge warblers. Four of these were “new” birds, the remainder were re-traps. Ten of the sixteen had already been handled this year, one on every visit, five on three visits, and four on two. Of the six new for the year re-traps, two had been ringed as juveniles: one in 2003 and the other in 2002 – but not handled in 2003. One adult from last year and two from 2002, were accompanied by the reigning oldest bird on site, an adult male, that was originally ringed in 2000, and as it was an adult then, we don’t know for sure exactly how old he is, but he is at least five years old and has made the journey to Africa and back at least five times.

This now means that we have handled thirty-nine different adult Sedge Warblers, twenty-one new birds and eighteen retraps from previous years or controls. This compares favourably with previous years: 22 by visit 3 last year and only 33 in total, 28 by the corresponding visit in 2002 and a total of 39; a total of 40 in 2001, with the first three visits missed due to foot and mouth, and 34 by visit 3 in 2000, with a total of 49 by the end of the season. The numbers of adults is not necessarily an indicator of the potential catch for the year, as breeding success and the number of juveniles caught mostly influences this. However it is an indicator of good survival over the winter, both of adults and juveniles. This is further supported by the observation of singing Sedge Warblers along a hedge which often has none, and only has them in years similar to thi8when adult numbers are high early in the season.

The rest of the catch this morning was made up of regulars such as Reed Buntings (3), Bullfinches (3) a couple each of Blackbirds and Long Tailed Tits, a few Great tits, Sylvia warblers were represented by males of Blackcap and Whitethroat, and a solitary Chaffinch completed the catch. No juvenile birds have been caught yet, and the females caught are in breeding condition with brood patches indicating that brooding is happening or imminent.

The evidence of brooding as shown by birds in the hand was supported by the activity of the local Cuckoos, one of which languished momentarily in a net before rolling over and flying off. At one point no less than four birds were visible at once, a group of three and a singleton, whilst yet another advertised close by. One of the group of three was showing what I presume to be display flight, rising and falling, rolling and gliding, and some deeper wing flaps almost like wing clapping. On top of this we heard the bubbling call of the female on four occasions, so assuming one call per female following an egg being laid, and only one egg per day being produced by a female, then we had four females in the area, with attendant males. It can be no coincidence that this level of activity was observed when the most numerous bird on the reserve, the Sedges Warbler, was just starting to incubate eggs. They must be the targets of our brood parasites.

Following the frost on the poles at dawn, it was very pleasant to feel the warmth of the sun from the clear blue sky, by nine o clock, but as is often the case when it is warm and sunny, the catching fell off rapidly. The finish time of ten-o clock was met with punctually, the taking down of the nets a warm job, but with the pleasure of seeing numerous Green Veined White butterflies, a Small Copper, and a Brimstone. The layers of clothes necessary to remain warm and dry at the start of the session, now are parts of the burden as we tramp back across the now dry fields back to the cars. Another successful and enjoyable glimpse into the private lives of the birds at Ashleworth.

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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