31/05/13 - Pliers at dawn

Following a successful breeding season in the Lower Derwent Valley NNR, up to 100 Greylag goslings and 200 adults currently remain throughout the site. The largest concentration is at Wheldrake Ings, where up to 80 adults are present, accompanying 80+ goslings.

Whilst many have bred on the wetter parts of the NNR, other broods have also been walked from small ponds and other water bodies in the surrounding area away from the reserve, such as this brood seen walking along the road at Storwood before making their way across the fields and onwards towards Wheldrake Ings.

During late May and early June when the goslings are of a suitable size for ringing, the young and adults (and any non-breeding moulting and flightless adults) are rounded up using our corale trap. This involves waiting for the birds to be in the right place and herding them gently through the water and willows towards the trap. We failed to make any catch last year due to the extensive flooding so we were looking forward to this year’s catch with the hope a good sample could be marked. Things went extremely well this year with an early catch and an impressive 71 Greylag geese and a single Canada Goose were caught. This included four re-trap Greylags from previous years and an impressive 51 goslings.

This is the largest single catch of Greylags ever taken in the Lower Derwent Valley and should help our understanding of the re-established population and how birds from this population may mix with ‘wilder’ Icelandic birds which winter in the valley. The WWT are keen to increase the numbers of Greylags ringed in the country to help monitor the population and add to our knowledge so this catch is even more valuable. National ringing totals over the last five years have ranged from 300 to 678 with this catch representing 14% of the annual UK five year average total. However, it was particularly pleasing to get 51 goslings as these birds have a known age and breeding location, and with national ringing totals ranging from 52 to 81 over the last five years, this catch represents 64% against the national five year average – a great result. With a team of volunteers the birds were quickly dealt with and released to re-group into their large crèche. After the successful round up we followed it up with a brood of seven Canada Geese goslings at Bank Island.

A total of 686 Greylags have been ringed in the Lower Derwent valley NNR, producing several interesting movements, some of which are shown below, including the two longest movements of goslings ringed in the valley.

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Ringed (1) - 29/05/08 - Wheldrake Ings, North Yorkshire

Recovered (+) - 09/09/10 Caerlaverock, Dumfries & Galloway, Scotland 207 Km

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Ringed (1) - 16/06/08 - Wheldrake Ings, York, North Yorkshire

Recovered (+) - 23/09/09 - Meathop Marsh, nr Grange-Over-Sands, Cumbria 131 Km

These goslings are also getting into the regular core wintering range of Icelandic Greylags, whilst the recovery below shows an adult ringed in the winter also heading north into the main wintering area of Icelandic birds.

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Ringed (6) - 02/02/07 - Wheldrake Ings, York, North Yorkshire

Recovered (+) - 15/09/08 - Loch Leven, Tayside, Scotland 300 Km

Several goslings have also moved north-east into the Ripon/Harrogate area which has also shown an interchange of birds between the re-established and wild populations, as shown below.

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Ringed (6F) - 02/03/03 - Lingham Lake, Nosterfield, North Yorkshire

Re-sighted (VV) - 19/04/03 - Bard, Midfjordur, ICELAND 1778 Km

Re-sighted (VV) - 09/03/04 - Lingham Lake, Nosterfield, North Yorkshire

Re-sighted (VV) - 21/01/05 - Castle Howard, North Yorkshire

Re-sighted (VV) - 11/02/05 - Castle Howard, North Yorkshire

Re-sighted (VV) - 19/02/05 - Lower Derwent Valley NNR

Greylag Geese in the Lower Derwent Valley provide a classic example of both how a species status can change in a relatively short period of time and through increased knowledge of ecology and movements. The species was a rarity to the Lower Derwent in the 1970’s with a mere five birds recorded during 1974. Since 1976 they have been recorded annually, followed by resident status first achieved in 1979 with a record count of 44 present in the December of that year. Numbers increased quickly to peaks of 110 in 1980 and 200+ in 1981 to 560 in 1988. In 1993 numbers reached 820 but over recent years (since 2000) counts of 2000+ are not unusual. Breeding numbers have increased likewise with the first breeding pair in 1978 increasing to ten pairs the following year and 25 pairs by 1986. Numbers of breeding pairs in and around the valley now typically average 40-60 pairs.

Following the goose catch a brood of four Jackdaws plus the adult bird were then caught from an Ash tree at Bank Island. This tree has been a regular nest hole for many years for a number of species including Barn and Tawny Owls, however Jackdaws have now been in residence for the last ten years and the owls have moved off to the nearby boxes.