Garden bird survey 2006

The only recent monitoring of the birds in our Cholsey garden and meadow had been restricted to taking part in the RSBP’s Big Garden Birdwatch. Those who have done this will be aware that this a carefully chosen hour when almost no birds put in an appearance!

So one New Year’s resolution for 2006 was to keep a daily record of all species seen or heard. Somehow we kept going through the year, only missing out when we were both away. Aside from discovering that we could amass 79 species in the year, we have learnt a great deal from the exercise – much more than expected.

We were to discover that the absences were even more interesting and surprising than the attendances. The year began on a high when on January 2nd. Tony flushed a Woodcock, the year’s only addition to our all-time garden list. The following day there were hundreds of Lapwing visible in the neighbouring field and flying near the Thames. This tempo continued on the 4 with fewer Lapwing, but now joined by 90 Golden Plovers and the local Skylark flock had swelled to 70. Sadly the Goldies failed to be long-time stayers as they have been in previous winters. January also proved to be the best month for seeing Fieldfares.

Collared Doves and Feral Pigeons enjoyed their best month in February, but over the year were well down. Perhaps the February highlight was a flock of 10 Yellowhammers on the 1st. There was to be no doubt about the March stars – Bramblings were easily seen from the kitchen window on most days. A Reed Bunting dined off a bird feeder – a recent habit apparently in harsh conditions. March proved to be the top month for Mallards, and after April they were hardly seen at all – most unusual for this once common visitor. Pied Wagtails peaked in March and again in October, evidence perhaps that these birds migrate more than most of us realise.

It astonished us to discover that April was the best month for seeing the majority of species recorded in the year. Goldcrest, Chiffchaff and Willow Warbler could not be overlooked. Whilst Linnet, Coal Tit and House Sparrow peaked in April, all then slumped badly. House Sparrows were only recorded on 11 days after April – why? The Whitethroat is a warbler that normally stays to breed on site, this year one sang briefly on the 17th and that was it for the year. It was a similar story for the Lesser Whitethroat but they have never been reliable stayers. May provided our sole record of a Cuckoo – about par for the course now. The resident pair of Green Woodpeckers suddenly disappeared towards the end of the month, on the day Southern Electric cut down some neighbouring trees – we suspect this included their nest site. May 20 saw the arrival of a Spotted Flycatcher. This bird was often seen over about three months and is thought to have nested nearby.

In June a Turtle Dove was a welcome visitor on three days, but did not stay as they have been known to do in recent years. At least one pair of Song Thrushes had been with us through the year until 25th June. Thereafter they were hardly seen at all until December. Our theory for this was the lack of tasty worms, slugs and snails on account of the hot dry conditions. A female Blackbird survived partly by taking a keen interest in all gardening activity, and snatching worms as soon as the ground was disturbed.

A pair of Bullfinches clearly included us in their territory and were often seen especially in July. From mid July to mid October we were surprised to discover that Dunnocks, Blue Tits and Chaffinches were in short supply. Was this what normally happens? – we shall see if this pattern is repeated in 2007. The usual passage of Yellow Wagtails began in earnest on August 21st and continued through into October. For us the most surprising absence was the almost total lack of Greenfinches in September and October. We are convinced this is not normal, and may the result of disease. September was memorable for regular sightings of Tawny Owls and the Hobby. The former had raised at least two young and were extremely noisy after dark. By day a Hobby provided great views on eight days as it pursued the local Swallows.

Although we had at least four Blackcaps over wintering, the year drew a close with all the thrushes taking centre stage. In November and December the Mistle Thrush, Fieldfare and Redwing were easily seen, but all were upstaged by the Song Thrush. Through December several males sang continuously, each trying to drown the song of the others. What a great note to end the year on!

Tony & Ro Rayner

P.S. Our detailed monthly records are available on request.

Field Voles

Our recording of small mammals, at Red Cow in Cholsey, is almost entirely done by noting what lies beneath about 30 metal sheets. These are inspected once a day if and when time permits.

The Field Vole, or Short-tailed Vole has for years been our most often recorded small mammal. Then in 2004 the Bank Vole, that had always been lagging behind in second place, overtook our long time leader. This was attributed at the time to habitat change. Recently planted hedges and trees were growing taller, resulting in a small reduction in open space and a little more shading.

The following year, we noted that Bank Vole sightings remained remarkably constant, but that the Field Vole had further declined. By April 2006 we realised that our Field Vole population was in free fall. We recalled reading about vole population crashes somewhere – so reference books were quickly consulted. There it was – Field Vole populations were subject to periodic crashes. Also it seems the reasons for these three to five year fluctuations is not really understood.

A couple of months later we were reading in wildlife magazines and newspapers that 2006 was indeed experiencing a sharp decline in vole numbers. So feeling a bit smug that we had detected a change several months before reading about it, we decided to delve into our records to see what they told us.

As we delved, that smug feeling began to evaporate. The reason being, that the warning signs had been there long before we realised anything was afoot. Way back in early June 2005 was the last time we had seen more than one Field Vole together.
Prior to that it was not unusual to discover two together, or nests full of youngsters. So it seemed that for well over a year, the evidence suggested a failure to breed on the site. No surprise therefore that no Field Vole sighting has been made since 9th June
2006.

The area is still regularly patrolled by both Kestrels and Tawny Owls, so clearly they are not dependant upon Field Vole snacks. Perhaps our Grass Snakes are to blame, yet further examination  of our records  suggests  otherwise.   Surely when we had
discovered nests full of young Field Voles, it might be expected that a day or two later a snake with a full tummy would sometimes be found nearby. This was not the case. So no explanation is apparent, and we wait so see if Microtus agrestis returns.

Tony & Ro Rayner

A brief statistical summary of our sightings appears in the Vertebrates Recorder’s Report in this years’s Naturalist.