By Stuart Brown
In each of the last two winters Fieldfares have concentrated in very large numbers during hard weather to feed in an area of un-harvested desert apples in a commercial orchard near Suckley, Worcestershire.
The site extends to approximately 30 acres of apple orchards grown in triple rows of trees pruned to 2.5 metres high. The orchard is surrounded and subdivided into three by 7 metre high hedges of Poplar and Alder trees for shelter, and further subdivided into six by a track at right angles to the hedges.
The extent of the Fieldfare flocks became apparent in mid December and the Christmas holiday created an opportunity to try to catch this infrequently ringed Thrush. Four lines of mist nets comprising a total of 1800 feet of netting were erected in one of the six sections of the orchard. The nets were set by 6.45 a.m., before dawn each day, leaving the orchard quiet well before the Fieldfares began to arrive from their roosts. The first birds began to fly in from about 7.30 and arrived in small numbers from several directions, the majority arriving in the next hour, but birds could be seen arriving throughout the day.
The majority of the Fieldfares were caught within a couple of hours of dawn, however when ringers could stay longer useful numbers could be caught all day, particularly when the weather remained overcast and the nets less obvious.
Fieldfares are normally difficult to catch because they take off and land very steeply and stay in the tops of the trees when roosting. The abundant fruit, much of which was still on the trees between ground level and 2.5 metres brought the birds down to net height. This combined with the near invisible nets and the large area of undisturbed orchard, resulted in good catches.
Eleven visits were made and the total number of new Fieldfares ringed was 1771. This compares with the average ringing total for the whole of the U.K. over the last 30 years of 1400 Fieldfares per year! The grand total ringed in the U.K up to the end of 2000 is just over 53,000.
The numbers of Fieldfares using the orchard at any one time was crudely estimated at between three and seven thousand. The daily ringing total for the first ten visits varied between 110 and 350 Fieldfares, only 47 (2.5%) were caught more than once.
In addition 316 other new birds were ringed (see table), including all the usual Thrushes, notably 85 Redwings, but also Blackbirds, Song Thrush and Mistle Thrush. Three Sparrow hawks that came along for a 'Take Away' were also ringed.
These numbers of Thrushes consumed massive quantities of apples, stripping the trees in days. The sub zero temperatures stopped at the end of the first week in January and the little remaining fruit began to rot quickly once it thawed. Saturday 12th January saw a good catch of 158 Fieldfares, the next day just three were caught, virtually all the birds had gone and no more ringing sessions were made.
We are still awaiting the details of the Fieldfare caught wearing a Swedish ring. Of the 157 foreign Fieldfares recovered in the U.K. since the ringing scheme began, 128 were originally ringed in Scandinavia (31 from Sweden). 515 U.K ringed birds have been subsequently recovered abroad. 296 were found in Scandinavia, the others included 135 in France and 43 in Italy.
The next few years will bring reports of some of our birds found dead or caught by other ringers to give further clues about their breeding areas, migration routes, life expectancy etc. The majority of the birds we caught were weighed and measured, aged and sexed by their plumage, analysis of this information is underway.
We are very grateful to the orchard owners for their
permission to ring in the orchard.
Many thanks also to Sue Adams of the BTO for providing ringing and recovery totals so quickly in order to put our efforts into context and to all the ringers who helped.
Table shows numbers of other species ringed in addition to Fieldfares.
(Note: this work was of course undertaken by fully qualified and licenced Bird Ringers working under the National Ringing Scheme administered by the BTO. Interestingly, fieldfares did seem to be present in Worcestershire in larger numbers than usual during the 2001-2002 winter and another large congregation was noticed in an orchard near Evesham. Ed)
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