CAHL2Winter bird food on arable and horticultural land

What it actually is

You take a block or a strip out of production and drill a mix of at least six small seed-bearing crops, chosen so that smaller farmland birds can get at the seed. It grows and flowers through the spring and summer, sets seed, and stands into the winter instead of being harvested.

GOV.UK's stated aim is an established winter bird food mix growing in blocks or strips, with plants that grow and flower during the spring and summer months and set seed to produce a supply of small seeds from late autumn until late winter. The page sets that in the context of food for smaller farmland birds, flowering plants that benefit insects, and support for integrated pest management.

The action is rotational or static, so you can move it around the farm each year or leave it where it is, subject to the two winter rule for a late establishment, set out further down.

Source: GOV.UK, CAHL2 action page, checked 05/08/2026.

What it pays, and what that comes to

The rate is in the panel at the top of this page. Multiplied out:

Source: arithmetic on the payment rate shown at the top of this page, which comes from Tilth's copy of the GOV.UK action catalogue and carries its own last-checked date. The 4 hectares is an illustration.

Is it worth it on your ground?

Step one: what it costs to put in. Seed, and on most mixes it is an annual cost rather than a one-off, because a one-year mix has to be re-established every year. Prices for mixes sold for this action:

Source: Boston Seeds, own listed prices and stated sowing rates, looked up 31/07/2026. Price your own mix, and check the one you buy actually meets the six small seed-bearing crops requirement on the GOV.UK action page, because not every wild bird mix does.

So the seed is somewhere around £54 to £125 a hectare a year. Cultivation and drilling are your own cost and we have not put a number on them, because they depend on your kit, your soil and where the block sits. Take your own figure off everything below.

One thing that moves it. A two-year mix is re-established every other year rather than annually, so over a three-year agreement that is two sowings instead of three, and the seed cost per year comes down by a third.

Source: arithmetic on the re-establishment rule on the GOV.UK CAHL2 action page, checked 05/08/2026.

Step two: what the ground would otherwise return. Gross margins per hectare for England, non-organic, in the 2023/24 crop year. Variable costs have already been taken off these figures, so there is nothing further to deduct.

Source: Farm Business Survey, Crop Production in England 2023/24, Rural Business Research, England, non-organic, 2023/24 column, checked 02/08/2026. The winter wheat figures come from a sample of 572 farms.

The agreement runs three years, so the comparison has to run three years too, and that ground will not be in wheat for all three of them. Three rotations, worked from the crop figures above:

Source: arithmetic on the crop gross margins in step two, from the Farm Business Survey, Crop Production in England 2023/24, checked 02/08/2026. These three are illustrations. Work your own out from the same crop figures.

Step three: the gap. After seed, the payment is worth £523 to £594 a hectare a year, depending which mix you buy, and before cultivation and drilling.

Source: the payment rate at the top of this page, less the seed costs in step one, set against the rotation averages in step two. The figures are subtraction. Cultivation and drilling are not in them.

Three things to set against those figures. What follows is Tilth's own reading rather than scheme guidance.

The survey reports one winter wheat figure, not first and second wheat separately. A rotation with two wheats in it carries a second wheat at the same gross margin as the first, which is unlikely to be how it turns out on your ground. We have not found a published split to cite, so we have not applied a discount of our own invention. Read the rotation averages as the generous end for the crop.

It is one year, and not a strong one. The same report's 2022/23 column put winter wheat's gross margin at £1,570 a hectare against the £988 above for 2023/24. A three-year decision resting on a single crop year is a shaky thing, and this particular year was the lower of the two. Against that stronger year the gaps above widen.

The field average is the right comparison here, and that is not true of every action. A buffer strip or an unharvested headland is confined to the outer edges of a field, which is systematically the poorer ground, so a field average flatters the crop side. This action is not confined to the edge. It can go on any eligible parcel, which means the gaps above are real gaps on ordinary ground rather than an artefact of the comparison.

Where that leaves it. On land that yields anywhere near these figures, the crop wins and this action is short by something between £170 and £313 a hectare a year before you have paid for a cultivation. That is the whole answer for average ground.

Which makes the choice of ground the entire decision. Because the action is rotational or static and is not tied to a field edge, you can put it wherever you like, and the only place it pays is ground that returns well under the rotation average: the shaded corner, the wet hole, the strip along the wood that never fills the trailer, the awkward triangle you turn on twice a day. The question is not whether CAHL2 beats your farm. It is whether you have four hectares that are losing you £250 a hectare against the farm average, and whether you know which four they are.

Does it work, and what makes it work better

This section is what we have found in published sources about the practice this action pays for. It is not scheme guidance, it is not Defra's or the RPA's view, and it adds no requirement beyond what the GOV.UK action page sets out. We have named every source and given the date we checked it. What it means for your ground is your decision.

Almost none of the work below is about CAHL2 by name. It is about wild bird seed mixtures, and this action is one way of paying for that practice. Read it that way.

The graded assessment. Conservation Evidence, based at the Department of Zoology at the University of Cambridge, summarises the published studies behind individual conservation actions and has independent subject experts score each one. Planting a wild bird seed or cover mixture comes out in their category Beneficial, on 49 studies. The expert scores behind that are 100 per cent for effectiveness, 65 per cent for certainty, and harms not assessed. Those two are not the same thing. Effectiveness scores only the size and direction of the effects that were reported, and certainty is the separate score for how many studies there are, how well built they are, and how much ground they cover.

Source: Conservation Evidence, action 594, Plant wild bird seed or cover mixture, in the Farmland Conservation synopsis, published 2013, checked 05/08/2026. Cite as Dicks et al. (2020), Farmland Conservation, pages 283 to 321 in What Works in Conservation 2020, Open Book Publishers.

What the studies found, both ways. Thirty of the 49 looked at birds, and 21 found positive effects. Fourteen UK studies, including one systematic review and nine replicated controlled trials, found higher bird abundance, density, diversity and species richness on wild bird cover than on other farmland habitats, and six found birds preferred it and used it more. Nine replicated studies from France and the UK found mixed or negative effects. Six studies found that mixes including kale attracted the most species or the highest numbers. Of the twelve invertebrate studies, seven were positive and four mixed or negative. Of the eight plant studies, six found wild bird cover one of the three best options for annual herbaceous plant communities.

Source: Conservation Evidence, action 594, key messages, checked 05/08/2026.

At the strong end, Henderson et al. 2004 surveyed 192 plots in lowland England and found bird density 50 times higher on preferred covers than on conventional crops, with kale supporting the widest range of species, and kale and quinoa holding their seed longest into late winter. The same study across 161 farms found bird numbers significantly greater on cover sown next to hedgerows than on the same crops midfield. At the other end, Browne and Aebischer found no difference between 1998 and 2002 in the fall in autumn grey partridge densities across 88 farms, whether they had planted wild bird cover or not, and Davey et al. 2010b, working across 2,046 one kilometre squares of lowland England, found no consistent association with farmland bird numbers and a steeper grey partridge decline where cover was present.

Source: Conservation Evidence, action 594, supporting evidence from individual studies, checked 05/08/2026.

Conservation Evidence say themselves that the studies are not directly comparable or of equal value, and that study size, design and relevance to your own situation matter more than counting which way they point. Their synopsis covers northern Europe, and the individual studies listed run from 1997 to 2010, so all of them predate this scheme and this action.

Source: Conservation Evidence, action 594, checked 05/08/2026, including the note under key messages and the synopsis title, Farmland Conservation: Evidence for the effects of interventions in Northern Europe.

What runs out, and when. GWCT reviewed the diets of 22 farmland bird species and report that the decline of farmland birds that feed on seeds in winter has been much steeper, at 39 per cent, than for other farmland birds at 26 per cent. Separately they studied seed availability across 40 fields in three English counties, and report that a field needs somewhere between 250 and 500 seeds per square metre to attract and hold birds, that on two farms with extensive stubble cover seed densities fell by 73 and 87 per cent between early and mid-winter, and that 30 per cent of all stubbles had insufficient seed by mid-winter.

Source: GWCT, Farmland bird diets and Seed resources for farmland birds, both checked 05/08/2026. Neither page states a publication date.

The second of those is about stubbles rather than sown mixtures. It describes the problem this action exists to answer rather than measuring whether the action answers it.

Sown crops run down too. GWCT's Allerton Project report that kale, quinoa and a cereal such as triticale or millet provided the best food sources, and that by January the seed of most crop species had become completely exhausted, teasel being the exception at only 70 per cent down because goldfinches can get at it. Their conclusion was to combine wild bird seed mixtures with supplementary feeding in the second half of the winter.

Source: GWCT Allerton Project research blog, Boosting biodiversity, feeding birds in the hungry gap, dated 07/11/2016, checked 05/08/2026. The page notes the recommendations come from one demonstration farm and may not generalise universally.

What we have not found. We have not found a published figure for what one hectare of winter bird food does to bird numbers on an ordinary commercial farm, as against the plot and field comparisons above. Nor anything that measures CAHL2 itself, which is no surprise given how new it is. And nothing above tells you how much of the difference between the studies that found an effect and the studies that did not comes down to how the cover was sited, sown and managed, which is the part you control.

What the sources say makes it work better. Farm Wildlife, a partnership of conservation and farming organisations publishing a single source of best-practice management advice for wildlife on farmland, advises siting seed mixtures near thick hedges that give birds safe cover, and aiming for 2 hectares of seed-rich habitat and cover crops per 100 hectares of farmland. On composition they advise a cereal base with an oil-rich component such as kale, linseed or quinoa. They give April or May as the ideal establishment time, note that autumn drilling produces seed only in alternate winters, and advise destroying the cover in late March or early April at the end of its final winter. They advise keeping insecticide and herbicide use to a minimum, and supplementary feeding around these areas from December through to March. The birds they name as benefiting are grey partridge, song thrush, tree sparrow, linnet, yellowhammer, reed bunting and corn bunting.

Source: Farm Wildlife, Wild bird seed mix, checked 05/08/2026.

Two of those have a measurement behind them further up this page: the hedgerow siting, and the kale.

GWCT's Allerton work adds two more. They found single species strips or blocks worked better than everything mixed together, and their trials gave an optimum of 60 kg of nitrogen a hectare, more than the 30 kg limit advocated in the stewardship schemes of the time. That was a different scheme with different rules, so read the current CAHL2 requirements before acting on the second one.

Source: GWCT Allerton Project research blog, dated 07/11/2016, checked 05/08/2026.

Supplementary feeding from December to March, and two hectares of seed-rich habitat per hundred, are other people's advice rather than requirements of this action. Neither appears in what GOV.UK asks of you, and the payment covers neither.

What you actually have to do

Establish a winter bird food mix as a block or strip on the land entered into this action, using a seed mix which includes at least 6 small seed-bearing crops which are suitable for smaller farmland bird species.

Once established, maintain it in a way that can reasonably be expected to achieve the action's aim.

Re-establish a 1-year mix annually and 2-year mixes every other year.

There is a timetable as well. Establish the mix in time for it to flower in the first summer after sowing, which GOV.UK says usually means by the end of June, and maintain it at the same location until late winter, usually around the end of February, in the year after sowing for a 1-year mix or the following year for a 2-year mix. If the action's start date makes that impossible, establish within twelve months of the start date instead. If you establish after the end of June, you must maintain it at the same location for two consecutive winters, so the rotational option is not open to you the following year. In the final year, do the action until late winter or the end date, whichever comes first.

Source: GOV.UK, CAHL2 action page, checked 05/08/2026.

What you cannot do on it

The seed mix must not include artichokes, reed canary grass, giant and intermediate sorghum, maize, miscanthus, sweet clover or tic beans.

You must not use the winter bird food mix block or strip for regular vehicular access, turning or storage.

Source: GOV.UK, CAHL2 action page, checked 05/08/2026.

Where it can go, and the cap

Arable land used to grow crops, temporary grassland, arable land lying fallow, and permanent crops both horticultural and non-horticultural, all below the moorland line.

Source: GOV.UK, CAHL2 action page, checked 05/08/2026.

CAHL2 is one of the limited area actions under SFI26. The rule is that the total eligible area you enter into any combination of them must not be more than 25 per cent of the total agricultural area of your farm. The others are CIPM2, CAHL1, CAHL3, CIGL1, CIGL2, WBD3, AHW7, AHW9 and AHW11. How the 25 per cent limit works.

Source: GOV.UK, SFI26 scheme rules and guidance, section 4.5, checked 23/08/2026.

Things worth watching

This section is Tilth's own reading of where this action is easy to get wrong. It is not scheme guidance, it is not sourced from Defra or the RPA, and none of it adds a requirement beyond what the GOV.UK action page sets out.

Check the mix against the six-crop rule, not against the bag. The requirement is at least six small seed-bearing crops suitable for smaller farmland birds, with the excluded species listed on the GOV.UK page. A bag sold as a wild bird mix is not automatically a mix that satisfies this action, so read the species list before ordering rather than after.

Six is a floor, not a recipe. Nothing in the requirement says which six, and the sources in the section above are clear that the choice changes how long the seed lasts. That decision is yours to make and yours to write down.

The aim runs to late winter and most mixes do not. GOV.UK's stated aim is seed from late autumn until late winter. The GWCT work above found most crop species exhausted by January. Nothing in the action requires you to close that gap, and it is worth deciding in advance whether you intend to, because the answer changes which species go in the mix and whether you are going to be feeding in February.

The re-establishment is easy to lose track of. A one-year mix goes back in annually and a two-year mix every other year. It is a requirement, and it falls in a part of the year when there is a lot else on.

Work the 25 per cent limited area cap out across all your actions at once. The cap applies to the combination, not to each action separately, so total them before you fill anything in.

Watch which block you put it on. The arithmetic above only works where the ground underperforms. Convenience to drill and poor yield are not the same thing, and it is the second one that pays here.

Rotational or static, and the choice has consequences. If you move it each year you repeat the siting and the mix decision three times against three different cropping plans. If you leave it, the same block carries it for three years, and the sources above note that disease and weed pressure can be a reason to move a plot.

Keeping the evidence

Also Tilth's own reading. GOV.UK sets the requirements; what follows is a practical suggestion about record keeping.

The records that would let you show you have met this action are what mix went in, when it was drilled, at what rate, and when it was re-established. In practice that means keeping the seed invoice or the delivery note with the species list on it, and noting the drilling date against the field at the time rather than at the end of the year.

This action also produces very little paperwork on the way out, because the crop that would normally close the record is never harvested. Dated photographs are worth taking for that reason: a block in flower in July and the same block standing in January show the action doing the thing it is paid for, and nothing else on the farm will show it for you.

Tilth records the mix, the drilling date and the photographs against the field as you go, so it is already assembled rather than reconstructed later.

The part only your own ground can answer

The arithmetic above says this action is short by £170 to £313 a hectare a year against a realistic rotation, and then says the whole decision is finding the ground where that is not true. We cannot do the second part for you from a national survey, because it depends entirely on which of your parcels give up two hundred and fifty pounds a hectare against your own average and which ones only feel like they do. Tilth holds your boundaries, your yield history and your NDVI in the same place, so that question has an answer sheet rather than a hunch. Request an invite.