A Case Study from a Manor House Estate in the North of England

Written by J.D.J Braithwaite and Charles Dutton

A Report Compiled for and on Behalf of the European Squirrel Initiative https://www.europeansquirrelinitiative.org/

With a host of woodlands to cover, a plan was devised to set up more than one feeder at a time (in separate woodlands) and culling efforts split across these. Once grey squirrels were significantly reduced (resulting in very few or no sightings across a number of visits); then new feeders in different woodlands were set up and efforts moved on to these locations. This cycle was repeated and in due course the original sites were revisited and targeted again. Therefore, the approach was to rotate the pressure across the woodlands and to return to original sites to mop up any remaining or new squirrels in the area. This approach was deemed advantageous because;

• It allowed for a footprint of pressure to be established early across the broader project rather than efforts only being focused in one location.
• It prevented a single feeder from becoming over-shot to the extent that visits from grey squirrels might reduce, while numbers in the area remain large, due to localised threat-related behavioural changes. Therefore, an unpredictable ‘broken rhythm’ approach was applied to the active
• It provided, at least in part, a degree of interception for wood-to-wood movement / migration from grey squirrels within the region being covered.

The project began in May 2018 and consisted of seven separate woodlands with six belonging to a manor house estate and one belonging to a neighbouring farm. In 2020 three new woodlands were added to the project from landowners surrounding the main manor house estate. This case-study report covers the period from May 2018 to September 2022. The project is on-going though only data from this time period are reported here. Throughout the project visits to the woodlands were constant, at around 2 or 3-visits per week on average. Severe weather, occasional forestry work, and the 1^st pandemic lockdown prevented access at various points during the 4-year period. Severe weather impacted on a couple of years, predominantly during the month of February. In 2022 there were three severe storms in February with one storm bringing down many trees across the Lake District. Furthermore, it was not clear whether pest control / conservation represented ‘essential’ activity for the first lockdown of the Pandemic and so no shooting took place during that initial period until clarification was provided.

Feed

The natural feeding behaviour of the grey squirrel follows what is known as the ‘Optimal Foraging Theory’. Here the food choices are based primarily on an assessment of the profitability of different food types, mitigated by the energy required to attain the food. By this account, squirrels are thought to always prefer food that is energetically favourable based on the nutritional content minus the energy it takes to obtain the item. The more calories contained within the food, the more likely it will be chosen first by the squirrel and pursued more vigorously. However, this foraging behaviour is also mediated by other factors such as the perceived risk from trying to attain the food sources (i.e., from predators). Risk perception itself is further mediated by both the lack of safe signals in the area (like bird activity) and the actual physical presence of threats (raptors, mustalids, etc). What the squirrel is really interested in is the best / most energetic meal in the woods, that is really easy to attain, and they perceive no or low threats in getting at it. So these factors trade off against each other and ultimately influence the squirrel foraging and feeding patterns.

In terms of what food works well in a feeder, peanuts provide an ideal staple as a base ingredient and are perfectly suitable. Some shooters prefer to use wheat, barley or maize. However, many report the greys not being overly interested in these less caloric offerings after some initial interest wanes. But peanuts never fail. On the whole grey squirrels can show more interest in a feed ‘mix’ rather than just one food type – as additional items can also provide more smells (to attract them in) and the activity of rummaging itself across food sources can be more stimulating for them. Peanuts are perfectly fine on their own a lot of the time – but a mix appears to work a little better. Other additional foods to add can include; large striped sunflower seeds, sunflower seeds, and black sunflower seeds. The squirrel will prefer the nuts and may ignore some of the other goodies, but the presence of some of the other items can be for smell and it keeps them on the feeder rummaging and blissfully unaware of the shooters presence nearby. When establishing a feeder in a given area it can be good to complement the food mix with a scent attractant (i.e., aniseed oil) or smear a chocolate nutty spread on the tree hosting the feeder (but also facing the shooter). The nutty spread, when placed correctly, will also articulate the squirrel into a position which should present the individual with a perfect brain shot in through the top on the skull of the grey squirrel.

Throughout the year grey squirrels can show variations in their foraging and feeding behaviour. For example, fewer greys will visit feeders during late summer / early autumn months. This is due to the availability of the natural woodland fruit and nuts during this period. Here grey squirrels are biologically hardwired to spend time in the tree canopy and harvest the banquet on offer. Towards late autumn and early winter grey squirrels will also begin caching shelled nuts / acorns to help them survive the harsh winter and early spring. They will show a reduced interest in feeders and are difficult to shoot due to the available cover still present in the woodlands at this time. Many conservationists will stop shooting them around this time and wait until early November, when food has fallen to the ground and the tree canopy has lost much of its foliage. At this time it can be a good idea to add items to the feeder with a higher caloric value, but are also still shelled (i.e., hazelnuts, monkey nuts, walnuts, chestnuts, fallen acorns).

There are several reasons for doing this. One is to get the feeder to compete for interest again, and against the food the woodland is providing naturally – but will also now be decaying. Another reason is to encourage caching behaviour. This now gives the squirrel two reasons to visit the feeder, one to eat and one to cache. Greys have been observed coming into a feeder containing these more substantive food sources, even though the woodland floor may also contain similar items (fallen acorns, hazelnuts, chestnuts, etc). The reasons for this are unclear but this may reflect the fact that the feeder is one single spot where all the goodies are, and is favoured rather than expend energy to find the best food spread out on the woodland floor. Once the feeder is stocked with such items what is often observed is a fast moving grey squirrel coming into the feeder, it will take the nut, quickly assess it, and invariable (at this time of the year) might run off quickly with the nut to bury it. However, after doing this once or twice the grey squirrel will stop to feed and not cache due to the energy already used in caching. Here the squirrel will often pause to nibble open the outer casing to get at the inner nut. This takes time and they tend to stay still when doing this, providing an ideal opportunity for the unhurried, humane, and lethal removal of the quarry. Once the grey squirrels have started to return to the feeder, one can swap back to a more typical feed – it is only a method to be tried across a few weeks at this time.

Working the target space

On occasion, it might be necessary to work the woodland floor around the feeder. The reasons for this are to provide additional clear viewing of the ground area to be targeted but also to create smells for the grey squirrel to come into the area and investigate. Overgrowth should be carefully trimmed between the tree hosting the feeder and the ambush position to allow the pellet to travel unimpeded and without deflection into its target area. This trimming should not be over-done. In some contexts the bare area may make the grey squirrel weary of predators and thus reluctant to enter the area (and so sometimes it is wise not to do this). However, on occasion it can be very effective and can be a method worth exploring. Permission should be sought to carry out such trimming and of course, healthy trees / branches should not be touched – the process outlined here is more concerned with redundant foliage in the area (woodland grass, brambles, bracken, dead and fallen branches, etc). It will not always be possible to work the space in this way, but when it can be implemented, it can assist with culling practices. Irrespective of working the ground space an assessment of the materials that may impede the travel of the pellet to the feeder area should be undertaken.

Figure 4: Working the target space around the feeder can help in terms of providing a clear route into the space so the pellet can travel unimpeded and free from deflections. Working the soil a little also provides smells to attract the grey squirrel to the area. However, the trick is not to over-work / over-clear the area. The grey squirrel still needs to feel safe from predators and this feeling is mediated by the presence of cover.

Hides for Ambushing

For ambushing it is useful for the individual to remain as hidden as possible. The summer months can, in some situations, provide enough cover on its own and simply using the shadows and a solid backdrop is often all that is needed. However, for the rest of the year what the woodlands provide naturally can be insufficient. In these circumstances a shooting hide is invaluable. Hides can be built from natural materials (fallen branches, leafs, dead foliage, etc) but they decay over time and require maintenance. An alternative is to complement what is naturally available with loose-leaf netting which can be added to the area and used as a kind of shooting blind, where the individual places themselves behind the netting and facing the feeder. The netting can be fixed to trees etc, or supported with hide poles, but ideally the netting should be above head height when the individual is sat down. For air rifle distances, netting works best if the individual stays low and shoots through the netting. Evergreens and holly bushes work well to provide year round backdrops. If netting is to be used it is worth thinking about if it is going to be left in place or not. This is important in that if it is to be left in the woodlands, care and attention needs to be given to prevent other wildlife from getting tangled up in the netting (i.e., deer). This can be done by securing the base of the netting into the ground and laying substantial fallen tree branches around the base of the netting and stretching out a few feet, thus preventing deer from being able to stand too close.

Otherwise it might be wise not to leave the netting in place at all. Pop-up hides are also a very useful solution. These can be secured in place and left in situ. There are no issues with wildlife getting entangled here. Pop-up hides give the most cover which can also be very helpful in adverse weather conditions.

Figure 5: A pop-up hide in situ in the woodlands. These can provide year round cover and are of particular use in the winter months. The hide itself does not need to be particularly well hidden – it just needs to hide the individual.

Figure 6: A wildlife trail camera placed in situ and facing a feeder in order to capture all visits to it and provide data on the number of visits, numbers of grey squirrels, and feeding times.

Stability & comfort: Shooting sticks and seats

Targeting feeders requires the individual to sit and wait, sometimes for a couple of hours or more. It is important the individual is comfortable. Therefore, a shooting seat helps to ensure a degree of comfort and provides a sturdy shooting position. In addition, shooting sticks can be used to ensure stability for the rifle. Tripod shooting sticks are very stable and some models are height-adjustable affording the volunteer considerable variability in the range of angles that can be supported with considerable ease.

Figure 8: Optimised modern ambush techniques utilise a steady shooting stick and seat. It is important the shooter is comfortable and stable. In the summer months hides can also be unnecessary and simply using the natural woodland and remaining still can be very effective. Face and hand coverings are essential for work at air rifle distances.

Thermal Imaging / Thermal spotters.

Thermal imaging can be used for both feeder-based and stalking approaches. The imager is something of a game changer showing heat signatures and thus revealing quarry that would otherwise be missed by the naked eye. Thermal is not only useful for locating quarry for lethal removal, but also to assess the area in general as it is often the case grey squirrels can be spotted in the distance and a healthy appreciation of numbers in the area can be made (and guide future visits). Furthermore, thermal can inform the individual with regards more general wildlife in the area. 

Figure 9: Thermal imaging is a game changing technology revealing the heat signatures of grey squirrels in the woodlands that might otherwise be missed by the naked eye. The thermal signature of the grey squirrel can be easily detected out to +80yds and beyond.

Figure10: With the use of ballistic modelling software (coupled to confirmatory practice on targets) the shooter can plot the trajectory of the pellet thus reducing guesswork over distance.

Part II: Overview: The manor house project

The project is located near to the Cumbria / Lancashire / Yorkshire border region. There are currently 10 sets of woodland subscribed to this project from four separate landowners. Several woods belong to a large Manor house estate. Other woods belong to two farming families (one each side of the manor house estate), and finally a landowner who lives away but rents his land to local farmers also contributed two additional woodlands. Local farmers have reported that these woodlands discussed here were indeed home to red squirrels when they themselves were children and were growing up in the area (circa 50 years ago). In addition, small populations of red squirrels are currently in residence less than 1 mile to the West, 1 mile to the East of this project (on other country estates) and 10 miles north of this region.

Estimates of the scale and size of the woodlands were made using Google earth maps and the distance / area function. Plotting from the furthest point south, through to west, north and then east including all lands within this perimeter, results in an approximate 243 acres in size. Of this the 10 separate woodlands make up around 70 acres in total (almost 30% of the total area). In between the woodlands are open fields and pastures used predominately for sheep and some cattle farming. Natural hedgerows and dry-stone walling provide potential highways for the grey squirrels to utilise while moving from wood to wood. The largest distance from the tip of one piece of woodland, to the one furthest away from it (and in a straight line) is 1.11 miles, with distances between neighbouring woodlands ranging from 339ft to 2,131ft and an average distance of 1,020ft. These distances are well within the foraging and localised migration range of the grey squirrel. There are no public parks in this region and only one public pathway which goes through an open field.

Importantly, there are no woodlands within the perimeter that are not part of the project. This helps to ensure the success of the project by either removing all grey squirrels, over time, or significantly suppressing their numbers to a level that would not be possible with more modest coverage. Therefore, a large footprint of pressure can be applied. Of course there will always be woodlands outside of projects that are not being controlled, and subsequently are in a position to provide incoming grey squirrels to the controlled area. However, having access to a large number of woodlands and all woodlands within a respectable area can help to ensure a wider clearance of the area and the subsequent control of the area. 

Table 2. An overview of the woodlands for the current case study. The names of the woodlands are pseudonyms.

1Note: The term “Predominately hardwoods” means that while conifers may well be present – it is in extremely low number to hardly any at all. In most cases hardwoods (of various species) dominate the woodlands.

2Note: It is interesting that even though the majority of these woodlands consist predominately of hardwoods, there once was a population of red squirrels residing in this region suggesting that the local ecology was sufficient to support them.

Results

Descriptive overall statistics for the project are given in Table 3. It is important to note that these numbers reflect moving around several woodlands and thus, whenever shooting a new section, numbers will be high until, after repeated sessions, the effects of constant pressure emerge. In addition these overall numbers pertain to the project that also included the addition of new woodlands in 2020 which in turn accounts for the increase in culls that year. Therefore, these data do not necessarily reflect pressure being applied to exactly the same spaces in all years. Irrespective of these observations, a clear negative trend emerges.

Table 3. The number of grey squirrels removed via shooting with an air rifle over the period.

The increase seen in some of the latter years (Table 3) might seem to go against the notion that shooting is effective at removing grey squirrels in the area. However, there are several important observations that modify this interpretation. First, it is important to note that shooting did not start until late May in 2018 (there were only 7-months of shooting for that year), whereas in 2019 culls represent a full 12-months of pressure. Second, in 2020 three new additional bits of woodland were added to the project. To examine this further and provide a more representative account of potential reduction in numbers, Figure 11 represents the successful removal of grey squirrels now separated in terms of the original project (as it started in 2018) and the additional woodlands added from March 2020.

As Figure 11 shows, once separated in this way both components of the project demonstrate a clear reduction in grey squirrels being removed from the woodlands year-on-year. With the frequency of visits to the woodlands being constant, this supports the notion that fewer culls represent fewer numbers in the woodlands in the first place. Pressure from shooting with air rifles, targeting feeders coupled to winter stalking is associated with a clear reduction in numbers. Between 2020-2021, the blue line (original project) deviates while, at the same time, there is a strong fall in culls on the three new woodlands data (red line). Arguably the most accurate way to interpret this is that the focus placed on the three new woodlands (and the attempt to make an early impact) detracted from the ability to maintain exactly the same pressure as previous years on the woodlands of the original project. Therefore, the co-occurrence of a steep drop in one component, and a slight levelling off of another, reflects a bias in effort at that time – at the cost of attention placed elsewhere. Note also that in the 2021-2022 cycle both components show a clear reduction in culls.

Figure 11: The number of grey squirrels removed from woodlands separated in terms of the original project and the additional three woodlands added in 2020 (dotted lines = trend lines for both components).

Figure12: Example data from two periods of shooting in Tarn wood. Missing data represents a period when this wood was not being shot (following two months of no sightings / culls). Initial shooting tends to bring good numbers and this is true for the start of most projects. There also tends to be good shooting to be had on the feeder in the months May through to July, including kits from the first breeding season. Quiet times on the feeder tend to occur from mid-August until the end of September when the grey squirrel spends a lot of time in the tree canopy eating the natural fruit and nuts. 

Note – the peaks on the graph generally correspond with when young grey squirrels are ‘kicked out’ from their home ranges (i.e., incoming dispersals).

However, if migration were a serious problem undermining the efficacy of the method this would make the clear prediction that a steady state of squirrel culls would occur over the 4-year period. That is to say, there would be no net reduction in the number of culls or at the very least – the effectiveness of the method would level off at a given amount and then remain constant. Clearly this is not the case. While incoming squirrel migration will be taking place, constant pressure on the woodlands appears to be preventing them from gaining a stronghold in the area. Therefore, neither breeding nor migrations are offsetting the effects of concentrated and year-long sustained shooting. Put simply, there are far fewer grey squirrels in these woodlands than there were and there is a year on year drop in the numbers seen and removed which cannot be explained by fewer visits to the woodland (the frequency of visits to the project was relatively constant over the 4-year period and continues at that rate).

The effectiveness of the current case study is limited in that only one shooter is contributing to the project. If more dedicated enthusiasts came on board this would indeed allow for a broader footprint of pressure to be implemented. However, this is not a limitation of the shooting method per-se, just how (through reasons of pragmatism in this case-study setting) the method was implemented here.

This observation also speaks to the issue of ‘efficiency’. In terms of the time taken to reach a satisfactory demonstrable reduction in numbers, then efficiency in this sense is indeed related to the time taken to reach that state. Therefore it would be more efficient to have reached 450 grey squirrels after 3, 2, or 1 year which would be possible if (i) the shooter had more time to invest (he is a volunteer shooter in his spare time), (ii) there were more guns on a given project, or (iii) if shooting were complemented by other methods being pursued with equal vigour (i.e., trapping). In contrast to these worthy observations, the fact that the number of culls reduced year on year, is consistent with the actual number of grey squirrels in the area reducing and is actually all the more impressive for having been achieved by one shooter, acting in his spare time. Therefore the current case study evidences the efficacy of what can be done at a base level. One can imagine how issues of efficacy could be improved if projects like this one were expanded. However, this is simply an issue of scale and not a limitation in the shooting method per-se. Therefore, these observations do not undermine the effectiveness or the efficacy of shooting.

If cost-effectiveness is used as a metric of efficiency then from the landowner’s perspective the project is 100% cost effective as this project has not incurred any cost to any of the land owners. This is not a situation we can expect to be rolled out or applied universally across other projects and so solutions in this regard should be considered. If time cost is being used then calculations not just on the time period invested for the numbers removed, but also the time invested that resulted in no culls needs to be examined. Sitting in a hide for 3-hours and having nothing to show for it could indeed be seen as being inefficient in terms of time investment. However, such instances are more likely to occur when numbers are low and thus, are an unavoidable consequence of success. The feeder method works well for most of the year and though there can be periods when activity on the feeder is low (late summer), this does not last for long. In addition, feeder methods can be complemented with woodland stalking during the winter months (November – February), can be vastly improved with thermal imaging, and further complemented (when possible) with drey poking and trapping.

To summarise, in the hands of a competent experienced shooter, air rifles coupled to optimised feeder / stalking methods are effective not just at controlling, but significantly suppressing the numbers of grey squirrels in rural woodlands. If carried out by volunteers or squirrel groups then they are financially efficient / cost effective for the landowner. The effectiveness of the method is dependent on; (i) constant pressure being applied over as large a collection of woodlands as is possible, (ii) constant pressure being applied throughout the year, and as suggested above, (iii) the burden of projects being shared by multiple shooters. Overall, the addition of trapping and using shotguns along with drey poking can represent a more holistic approach on large estates – where a broad portfolio of methods can make a huge contribution. Consequently, it is erroneous to look to one method, one singular approach, to suit all situations and contexts. Going forward the key will be to know which method should be pursued and in what context. This can be seen as a ‘mapping’ exercise of optimising ones approach, by drawing on the most appropriate methods (or a combination of them) for a given scenario. Irrespective of the method chosen, it will need to be applied in a sustained and coordinated manner in order to ensure success with regards turning the tide and achieving year on year reductions in the number of grey squirrels in our woodlands.

Volunteer Red squirrel groups

In the magazine for the British Association for Shooting and Conservation (BASC), Braithwaite reported findings from the West-Lakes Squirrel Initiative (WLSI) showing increased sightings of red squirrels coinciding with noted culls of grey squirrels. A subsequent offline analysis of these data revealed a correlation coefficient of around .70 {see Shooting and Conservation, ’Fighting Back’ Nov 2017 to view the original article} between these two sources of data. In the north of England there is a large and growing movement of people getting involved in red squirrel and woodland conservation. These volunteers may go out and report sightings (of either species) helping the shooters coordinate their efforts, they may report sightings of red squirrels with suspected parapox virus, or report sightings of damage to woodland trees. In addition to these admirable efforts, the shooter (typically with an air rifle) will seek to intervene as when necessary in an effort to address the situation. The presence and contribution of these groups has been largely ignored in debates surrounding the efficacy of air rifle methods. As a consequence, no detailed analysis of the efficacy of volunteer red- squirrel conservation groups has ever been carried out. While localised successes are reported (Braithwaite 2017), the true impact of these groups, as an en-masse effort, awaits evaluation. Future assessments of the efficacy of shooting in the control of grey squirrels will need to fractionate the different forms of shooting (shotguns, cartridge rifles, air rifles), with particular attention to the use of air rifles (as they have been ignored in reports to date). In addition, a clear examination of the 21^st Century culling methods outlined in this case study and the involvement of many volunteer red squirrel conservation groups is now unavoidable. Once done, the utility of air rifles and volunteer groups will be difficult to avoid by organisations like the Forestry Commission, Woodland Trust, and others if they are serious about the suppression and indeed removal of grey squirrels from regional areas.

Going Forward

The findings presented in this case study establish that shooting grey squirrels with air rifles and utilising an optimised approach is an extremely effective method for suppressing numbers of the grey squirrel. It is effective and humane. Having done this it should also be acknowledged that a more holistic approach will likely pay even more dividends with perhaps trapping and drey poking being highly complementary². There are ways to optimise these methods as well to ensure they provide an effective and efficient solution. Government grants are becoming available for woodland replanting schemes which can be red-squirrel friendly. Going forward it would be beneficial if a component of these grants went to the volunteers and / or squirrel conservation groups to provide some financial assistance with implementing some projects – especially larger estate projects. The financial amounts involved need not be large. A modest investment would help support efforts across many hectares with feeders, feed, wildlife trail cameras, hides, etc. Volunteers would still be giving their time freely and so such costs for resources should be balanced against the potential (and avoided) costs of salaried members of the estate team spending the hours in the woods when they are likely needed elsewhere.

² Drey Poking is not viable in woodlands containing grey and red squirrels as it is not obvious what species is occupying a given drey. Therefore there are constraints on where drey poking can be utilised as it is likely untenable in some contexts.

Acknowledgements 

Thanks are due to all those that have supported this (and other) projects currently underway in the north of England. In particular, we would like to thank, the Manor house owners who wish to remain anonymous. We would also like to thank Gavin and Becky Lonsdale, Mike, David, and Richard Crackles, Ron and Anthea Forbes, Chris, Dave, Claire, and Peter Middleton and many locals in the area that are supportive of our efforts and contribute in so many ways. We would also like to thank Peter and Iona Frost-Pennington, Peter Wallen, and Ronnie and Judy Phizacalea for their support more broadly and on other projects. Thanks are also due to Steve and Karen Hopps (Sedbergh Red Squirrel group) and to the West Lakes Squirrel Initiative (WLSI) for contributing with a supply of feeders. Finally, thanks to the membership of the European Squirrel Initiative (ESI) for support in the preparation of this document.

“Too often we have heard that shooting cannot control grey squirrels, but following the publication of my Grey Squirrel Management handbook, Dr Jason Braithwaite has done an in-depth study on controlling grey squirrels using an airgun at bait stations over a period of time and as the IUCN guidelines and Prof. Simberloffe said, airgun shooting at baits stations can be an effective method of ‘knocking the population down before you mop up’. 

Well done Jason and vert good bit of work.”