Wednesday, 14 March 2012

MEGA - First-ever RED-THROATED DIVER for College Lake



WEDNESDAY 14 MARCH

Well for most of the day, it was grey, overcast, dull and cool. There was little if any wind and visibility was poor over any sort of distance.. At around midday, the sun started to burn through and a lot of the low cloud started to clear - temperatures increased to about 10 degrees C and eventually the afternoon was quite pleasant, with bright sunshine and clearing skies.

Sometime in the early afternoon I received a call from Mike Collard informing me that Paul Reed had discovered a 'diver species' at College Lake BBOWT - most likely a RED-THROATED - a local mega. At the same time I was also being bombarded with news of rare birds all over the area, including a drake Garganey and 2 Pied Avocets at Amwell (per Barry Reed, Mike Ilett), a Common Stonechat at Batford (Darin Stanley) and a Scandinavian Rock Pipit at Caldecotte North (per Ted Reed). The diver was by far the most important and that is where I made a beeline for............

COLLEGE LAKE BBOWT (BUCKS)

I arrived on site at about 1600 hours immediately connecting with the now confirmed RED-THROATED DIVER in the car park, courtesy of Simon Nicholl's telescope. The 13-mile journey had taken me over 45 minutes, mainly because it had coincided with school leaving time and BCC were undertaking numerous pothole repairs on the Wigginton road. I was particularly frustrated and anxious, as both JT and SN had warned me that the bird was flying around and seemingly trying to leave.

Anyhow, I was very lucky - the bird had stayed. I joined Jeff Bailey, JT and Anna Marett and together we all walked down to the reserve Octagon Hide, where Roy Hargreaves, Mike Collard and Dave Parmenter were getting much better views. I had also briefly seen the finder Paul Reed by the centre. I was just setting my 'scope up when yet again the bird took flight - and circled the pit three times gradually gaining height before flying back down again and splash-landing. The bird looked up occasionally as it circled round, perhaps peering in all directions to see how clear the sky was; it was still pretty misty to the north.

The bird put down back on the main pit and allowed closer scrutiny. To my surprise, it was an adult in near full breeding plumage, with an extensive deep red throat-line and some neat striping on the hindneck. Most of the head was pale grey too although the mantle, upperwings and sides were largely still in winter plumage, noticeably chequered. It dived frequently, staying down for 20 seconds or more, and also snorkelled (looking underwater for food). I did not see it perform a successful dive although it could of course have found some small prey. It swam from left to right, mainly at a distance of 100 yards, and was on constant alert. The odd Black-headed Gull harassed it.

Within no time at all, it was back in the air, and it repeated this routine on at least three occasions during the first hour I was present. Tempting it to enter Hertfordshire airspace, it never did and eventually I got tired of waiting. A few closer views were had when it landed a tad closer to the Octagon but it always remained relatively distant. Dave Hutchinson did well in getting both a shot in flight and on the deck (see attached) whilst Roy obtained a fair bit of video footage.

I left for a while to twitch Roy's Rock Pipit at Wilstone but whilst there, JT kindly rang to say that the bird now appeared to have more momentum about its efforts to leave and that I should quickly get back. I did just that and joined the 'new' observation team, including Ian Williams, Nik Maynard, Paul Moon, young Charlotte and of course, Anna and Joan. The bird was still in flight as I returned and within a few minutes had entered Hertfordshire airspace, crossing the B488 southeastwards towards Tring Station. This was at 1740 hours. By now, the bird was extremely high in the sky, and for a while it headed NE towards Ivinghoe Beacon and the escarpment. It then decided to head back for College again but instead of dropping height, it continued to gain and suddenly seemed to have intent on its mind. I lost it as it flew towards the sun but a sharp-eyed Charlotte quickly re-intercepted it. It was now making a direct beeline for the reservoirs and flew slightly south of west. We all kept on it as it flew very high, firstly over Startop's and Marsworth and then as it continued over Wilstone. I lost it from view at about 1747 hours, the bird seemingly continuing west on its journey, perhaps navigating towards the Severn Estuary as many displaced seabirds inland do. It had been a terrific few hours and well done to all those involved in the finding and access arranging.

It represents only the eighteenth record (32nd individual) of this species in Bucks and the first since November 2005 -:

1) One was shot near Aylesbury Station prior to 1910;
2) An adult was present on Spade Oak GP, Little Marlow, from 27th October to 7th November 1952;
3) One remained on the River Thames at Hurley from 11th-31st March 1970;
4) One was seen at Calvert on 13th-16th February and again on 22nd February 1976;
5) One remained at Wotton Underwood Lake from 5th-12th March 1978;
6) One visited Willen Lake on 14th March 1979;
7) Another was present at Willen from 7th-10th March 1980;
8) A third visited Willen on 7th February 1986;
9) A slightly oiled adult was present on Weston Turville Reservoir from 8th-10th December 1987 before being taken into care; it subsequently died;
10) A remarkable flock of 14 birds touchlanded at Willen Lake during sudden snowfalls on 2nd April 1989. Six remained overnight and flew off shortly after dawn on 3rd April, with a further two departing at 0900 hours;
11) A juvenile remained at Spade Oak GP from 16th December 1990 until 12th January 1991;
12) One was on Eleven Acre Lake at Stowe School on 20th January 1994;
13) A second bird was found at Stoke Mandeville Hospital on 2nd February 1994. It was oiled and taken to St Tiggywinkles Wildlife Hospital at Haddenham;
14) An adult female was found on the bank of Weston Turville Reservoir on 14th March 1996. Despite being taken to St Tiggywinkles, it died on 15th;
15) A diver seen briefly on Taplow Lake on 11th November 1997 was presumably that Red-throated Diver found next day at nearby Bray GP, Maidenhead, in Berkshire;
16) One at Startop's End Reservoir on 22nd December 1997 swam into the Bucks partition of the reservoir;
17) An adult visited Spade Oak GP on 27th November 2005

As regards occurrences at Tring Reservoirs, only the 6th since 1958 -:

1) A male picked up disoriented in Hitchin on 29th November 1958 was released at Wilstone Reservoir on 30th where it was later found dead on 6th December;
2) One was found dead on Wilstone on 22nd November 1959;
3) One remained at Tringford Reservoir from 28th February to 3rd March 1962;
4) One visited Wilstone briefly on 28th April 1975;
5) One visited both Wilstone and Startop's on 22-23 December 1997

In addition to the RED-THROATED DIVER, College Lake also boasted another first today - a CETTI'S WARBLER. Showing well on occasions in the reed-filled ditch adjacent to the track to the Octagon Hide, the bird was still singing this evening.

Also present on the main marsh were 2 COMMON SHELDUCK, 7 Shoveler, 8 Gadwall, 10 Common Redshanks, the OYSTERCATCHER pair, 8 COMMON SNIPES and 2 RINGED PLOVERS, the latter my first in the county this year.

WILSTONE RESERVOIR, TRING (HERTS)

Over at Wilstone, I was very pleased to refind Roy's SCANDINAVIAN ROCK PIPIT of this morning. Just like then, the bird was closely associating with the long-staying WATER PIPIT, the two birds showing very well this evening on the concrete foreshore not far east of the main car park steps. When flushed, the two birds flew to near the jetty but soon returned. Jeff Bailey and a couple were also on hand to enjoy the spectacle. The two birds were like chalk and cheese, the Rock Pipit being much greyer on the upperparts with less of an eyestripe and much heavier sullied and striated underparts. The wintering Water Pipit was now in somewhat transitional plumage, the streaking now more sparten and the underparts much whiter. Some grey was coming through on the head and face, but the back was still a nice soft brown.

Otherwise, DARK-BELLIED BRENT was still in its favoured field and the immature drake Common Goldeneye was off of the jetty; no Sand Martins