Over the 2023 autumn period and living locally, I have had the opportunity to witness what can only be described as an unprecedented birdwatching ‘spectacular’ on the West Fen, an area of former fens drained in the early 1800’s and now primarily down to intensive arable cropping, situated at the northern edge of the Lincolnshire fenland basin between Boston and Spilsby. 

 

Such has been the sheer scale in number of birds, a bird watching pal of mine who shared the experience rather cheekily came out with the above quip regarding Frampton - but to be fair we would both, of course, not wish in any way to belittle the efforts of the RSPB staff and all the volunteers who have worked so hard to make that reserve the place it has become today. 

 

Nevertheless, the various species involved and the conservative estimates of their numbers, has been nothing short of remarkable - particularly at this relatively inland site, situated as it is some 12 miles from the nearest point on the coast. 

Below are some of the estimated maximum counts recorded for selected species:- 

 

• 9000+ Pink-footed Geese 

• 400+ Greylag Geese 

• 206 Whooper Swan 

• 650+ Teal 

• 450+ Wigeon 

• 9000+ Lapwing 

• 54 Dunlin 

• 55 Curlew 

• 3000+ Black-headed Gulls 

• 1000+ Common Gull 

• 1000+ Woodpigeon 

• 9000+ Starling 

• 400+ Jackdaw 

• 600+ Rook 

 

The reasons for this astonishing number of birds of several differing species, concentrated into one relatively small area are, I would surmise, two-fold:- 

 

Firstly, the intense rainfall in conjunction with Storm Barbet in late October, followed by further prolonged rainfall episodes on the West Fen - much of which is at, or in some places below sea level - have seen large swathes of the arable fields either temporarily totally flooded, or otherwise continuing to support large pools of standing water. 

 

Secondly, it is the bumper availability of food at this time of year - in the form of the post-harvest residue from sweetcorn crops. Sweetcorn is now grown on the West Fen on a substantial scale to provide fuel for three large local biodigester set-ups, with the methane gas produced used to power engines to generate electricity for the National Grid. 

The totally waterlogged soils in autumn 2023 will have also been forcing many of the invertebrates they contain to the surface, providing a further much greater than normal food source. 

 

In addition, the area in question is essentially a vast open space, supporting several 100+ acre sized fields with very few hedgerows or trees, and for the most part free from human habitation or activity - thus offering birds little in the way of disturbance while busy feeding and wide uninterrupted views for predators across the surrounding landscape. 

 

In the local area the move away from arable crops for food production to bio-fuel ones (with sweetcorn being the most favoured) has substantially increased over the last few years, primarily due to the construction of the three large multi-million-pound bio digester complexes mentioned, all within a 5 mile radius of the West Fen. 

 

It is the method of harvesting this sweetcorn in the autumn period that is key to providing such an abundant early food source for migratory geese and swans. 

 

For the sweetcorn plants to be used for the bio-digestion process, they firstly need to be finely chopped into fragments by the foraging machines before being fired directly into following tractor hauled trailers. In the process of doing this many individual corns, as well as whole cobs, fall away to the ground beyond the reach of the harvesters and remain on the soil surface, thus providing a bumper food supply for a range of bird species. 

 

Locally it was as little as four years ago that I first noticed how Pink-footed Geese had identified this ready food source and begun to capitalise on it, moving from one harvested sweetcorn field to the next – with my maximum count for this species being what I then thought was an impressive 597 birds. 

 

Last year this food source proved much more short-lived, with greatly reduced counts of Pink-feet as a result, following a dry autumn and the opportunity for the fields in question to either be quickly ploughed or top cultivated with a follow-on crop. 

 

This autumn however, due to all the heavy rain it was a totally different story, with the majority of the ex-sweetcorn fields remaining partly flooded for several weeks and unable to be ploughed, thus enabling the numbers of Pink-feet to build and build to at least 9000 birds - a quite astonishing number so far inland. 

 

Similarly, this autumn the visiting Whooper Swans significantly increased in number, more than doubling their previously maximum count, rising from 87 to 206 birds. 

 

A new addition to the mix this year were Greylag Geese, peaking at over 400 birds - probably mainly, if not all, being visitors from the Tattershall /Kirkby on Bain pit complexes a few miles to the west. 

 

This sweetcorn ‘feast’ and the presence of flooded pools also resulted in perhaps the most bizarre sight of all, with on one particular day in excess of 650 Teal and 450 Wigeon all congregated together on a single, large floodwater pool out in the middle of an arable field. As to where all these ducks had suddenly come from one can only guess?

 

In addition to the substantial number of Black-headed and Common Gulls (c3000 & c1000 respectively), enticed to gorge on all the flooded-out soil invertebrates, the numbers of Lapwings steadily increased to at least 9000 birds, providing a phenomenal sight at one point when they all took to the air en-masse following the sudden presence of a quartering Marsh Harrier. The Starling numbers have been equally impressive, also peaking at 9000+ birds. 

 

Finally, a party of no less than 52 Dunlin, probing around the margins of one of the flooded field pools, was certainly noteworthy in terms of such a large number being so far inland. 

 

As to whether we will ever see this combination of a prolonged and abundant food source and such wet autumn at exactly the same time, and a repeat of such a huge numbers of birds, we will have to see. 

 

I will certainly be keeping a close watch! 

 

Garry Steele - 27 December 2023