Wood Ant Translocation Guidance
Wood Ant Translocation
Wood Ant Translocation Good Practice Guidance
Contents
Background 3 Deciding on method of translocation 12 Acknowledgements 29 Wood ant nests 4 Reason 1: translocation of nests under References 30 The wood ant year 5 direct threat of destruction Conservation status of wood ants 6 German method 13 Appendix I 31 Whole nest excavation method 16 The shining guest ant (formicoxenus nitidulus) 7 Reasons 2: translocation to increase Overview UK distribution, habitat preferences and colony structure of each species Myrmecophiles 7 resilience or for ecological restoration Partial nest translocation 18 Appendix 2 32 Permissions 8 Release of mated queens 20 What to consider when recording habitat features at donor and receptor sites Health and safety 8 Translocation of narrow-headed ant nests 22 Appendix 3 34 Translocation principles 9 Whole nest translocation method for Pros and cons of different translocation methods Reasons for translocation of wood ants 9 narrow-headed ants 25 Appendix 4 36 Recording the translocation 28 Stages of translocation 10 Decision tree to help select method of translocation Site habitat assessment || Post-translocation monitoring 28 Appendix 5 37 Using felt tiles 28 Translocation recording form template Monitoring schedule 28 Signs of success 29 Appendix 6 38 Separating the different species of wood ants
Background
The aim of this guidance is to encourage a more structured approach to the translocation of wood ant nests and ensure that translocations are based on the most up to date methods. Translocation of wood ant nests is a very specialised area of conservation and it is hoped that this guidance can provide useful tools for non-specialists (land managers, consultants, developers etc.) that may need to carry out this type of work.
Our knowledge of wood ant behaviour and ecology is increasing all the time, as is our understanding of the effects of translocation on colonies and their ability to tolerate disturbance. As such this is seen as a working document that will likely be updated over time as new information becomes available.
There are documented examples of wood ant translocation projects that have been conducted in the UK and further afield. Experiences gained through these projects have helped to shape this guidance.
This guidance will cover the following mound building species of ants: Southern Red Wood Ant (Formica rufa), Scottish Wood Ant (Formica aquilonia) and Hairy Wood Ant (Formica lugubris). These species have different habitat requirements and different colony structures (see Appendix 1). For the rest of this report these species will be termed “wood ants”.
This guidance also includes Narrow-headed Ant (Formica exsecta) which is also a mound building ant and related to the wood ants, but differs in biology and ecology. These differences mean that a different approach to translocation is required for this species, as such it is discussed separately to the wood ants on page 22.
“Our knowledge of wood ant behaviour and ecology is increasing all the time, as is our understanding of the effects of translocation on colonies and their ability to tolerate disturbance.”
Wood ant nests
The nests of these species are highly complex structures and are built over years, sometimes decades.
The thatched mound on the surface is only a component of the whole nest and a significant proportion of nest structure also exists underground. A single colony of wood ants can consist of multiple, interconnected nests with established foraging trails existing between them and the surrounding habitat.
Although some nest mounds contain a single queen (known as monogyny), there can be multiple queens within a single wood ant nest mound (polygyny). It is essential to establish whether a nest mound belongs to a population known to be generally monogynous or polygynous (see Appendix 1) and capturing the queens is critical for the ability of the nest to survive – particularly the case in monogynous nests. If the queen is lost or killed the nest will become extinct. Polygynous colonies have the ability to be single nest (monodomy), or multi-nest colonies (polydomy). Polydomous nests result from mated queens returning to their natal nest. One of these queens can then create a “bud” or “satellite” nest nearby which remains connected to the natal nest. Therefore a single related colony can consist of several interconnected nests. A woodland may contain a large number of nests, however if all these nests are related interconnected nests then the actual population size will be low (owing to the ants being genetically related to one another).
To reduce competition for resources, wood ants defend their nests and territories aggressively from other wood ants and also other ant species. Wood ant colonies that are unrelated to each other will fight aggressively when they encounter each other although separate colonies can co-exist in the same area of woodland by maintaining their own territories. The size and quality of habitat will determine how many colonies can co-exist, and how big (sizes of individual nests and numbers of nests) these colonies can be.
Ants are predatory insects, foraging on a wide range of invertebrates at all levels of the woodland, from the ground to the tree canopy. Invertebrate prey is predominantly fed to the developing brood (larvae).
The diet of the workers mostly comprises honeydew from aphids in the tree canopy. Nests will have established foraging routes into the woodland around them. Trees both young and mature are a vital source of aphids. The wood ant workers will often visit particular trees to feed, and not necessarily those closest to the nest.
A Southern Wood Ant (Formica rufa) worker guarding a collection of aphids.
The wood ant year
It is useful to understand how the activity of ants changes throughout the season as this often dictates how and when nests can be moved. Opposite is a generalisation and timing of events will vary depending on factors such as species, location within the UK, nest altitude, local climate etc.
More detailed information on wood ants and their ecology can be found in the resources below:
- Cairngorms National Park Authority (2021) Guide to Wood Ants of the UK and related species
- Robinson, E.J.H. & Stockan, J.A. (Eds) (2016) Wood Ant Ecology & Conservation. Cambridge University Press.
- Robinson, E.J.H. & Stockan, J.A. (2021) Wood Ants (Formica rufa Species Group) in Encyclopedia of Social Insects. Christopher K. Starr (Ed). Springer, Germany.
- www.woodants.org.uk
- www.antwiki.org/wiki
Calendar of Wood Ants
Timing | Event |
---|---|
November-March | Hibernation |
March-April | Spring swarming. Timing of emergence is dependent |
on ambient temperature and levels of sunshine. In southern UK wood | |
ants can emerge as early as February, depending on weather. | |
Activity of the workers begins when the internal nest temperature rises to | |
between 25 – 30°C. | |
Workers will then cluster on the surface of the nest in a dense mass | |
to absorb heat from the sun (see Figurel below right). | |
May-October | This is the main season for wood ant worker activities. This includes |
foraging, aphid farming, repairing and building nest. The number of active | |
workers involved in foraging peaks in mid-summer. | |
June-September | Raising worker offspring |
May-June | Raising sexual offspring (from eggs laid in late winter/early spring). |
May-June | Emergence of males and virgin queens, mating flights. This is usually confined |
to a relatively short window of time. In southern England can be as early as | |
May, in northern Scotland may be as late as July/early August. |
Calendar of Narrow-headed Ant
Timing | Event |
---|---|
November-March | Hibernation |
March-April | Workers become active again (but do not show swarming/clustering behaviour |
as seen in wood ants). Spring emergence in Scotland is likely to be later than | |
southern England. | |
May-October | General worker activity and foraging, aphid farming, repairing and building |
nest. Number of active workers involved in foraging peaks in mid-summer. | |
May-June | Raising sexual offspring (from eggs laid in late winter/early spring). |
June-September | Raising worker offspring |
July-August: | Emergence of males and virgin queens, mating flights. This is usually confined to |
a relatively short window of time. |
Figure I
Conservation Status of wood ants
Wood ants are not legally protected. However some of the species are of conservation concern and listed as priority species for conservation. All public bodies have a biodiversity duty to protect and conserve all wildlife, not just specific protected sites or protected species.
It is considered good ecological practice to avoid deliberately harming wood ants and their nests, particularly in light of their important roles within woodland ecosystems.
- Environment Act 2021, Natural Environment & Rural Communities Act (2006) Section 40 and Section 42 (England and Wales respectively), Nature Conservation (Scotland) Act 2004 (Scotland), Wildlife and Natural Environment Act (Northern Ireland) 2011 (Northern Ireland)
Overview of the conservation status of each species:
Species | Status |
---|---|
Southern Red Wood Ant (Formica rufa) | IUCN status: “Near Threatened” (last assessed 1996) Subject to an action plan in the Warwickshire, Coventry and Solihull Local Biodiversity Action Plan and the Harrow (London Borough) Biodiversity Action Plan. |
Scottish Wood Ant (Formica aquilonia) | IUCN status: “Near Threatened” (last assessed 1996) Northern Ireland Priority Species (Wildlife and Natural Environment Act (Northern Ireland) 2011) Subject to an action plan in the Cairngorms National Park |
Hairy Wood Ant (Formica lugubris) | IUCN status: “Near Threatened” (last assessed 1996) Subject to an action plan in the Cairngorms National Park |
Narrow-Headed Ant (Formica exsecta) | Classed as Endangered in the UK according to the GB Red List. Natural Environment & Rural Communities Act (2006) Section 41 – listed under “Species of Principal Importance” Nature Conservation (Scotland) Act 2004 – listed as a priority species on the Scottish Biodiversity List under the categories “Conservation Action Needed” and “Avoid Negative Impacts”. Subject to an action plan in the Cairngorms National Park (2019−2024) and is listed on the “Devon Special Species” by the Devon Local Nature Partnership. |
The Shining Guest Ant (Formicoxenus nitidulus)
The Shining Guest Ant is an ant species that lives inside wood ant mounds. It creates its own nest inside the wood ant mound and forages within the nest, protected by a cuticle coating that the wood ants find repellent. It is not found within every single wood ant nest and due to its tiny size and secretive lifestyle, very little is known about this species. It is listed as a priority species for conservation in England and Scotland (see below). Its status as a priority species accords priority status to wood ants, as it is dependent upon Southern Red Wood Ant, Scottish Wood Ant and Hairy Wood Ant in the UK for its existence.
Overview of status:
- Natural Environment & Rural Communities Act (2006) Section 41 (England – “Species of Principal Importance”)
- Nature Conservation (Scotland) Act 2004 listed as a priority species on the Scottish Biodiversity List under the category “Watching Brief Only”.
- IUCN status: “Vulnerable” (last assessed 1996)
- Subject to an action plan in the Cairngorms National Park
Myrmecophiles
In addition to the ants themselves, wood ant nests often play host to other invertebrate species which depend upon the conditions within the nest for all or part of their lifecycle (known as myrmecophiles*), making the nests small ecosystems in their own right.
- For more information on myrmecophiles in wood ant nests, see Robinson, N.A. & Robinson, E. J. H. (2013) and Chapter 8 of Robinson, E.J.H. & Stockan, J.A. (Eds) (2016)
Permissions
Where translocations are necessary, these should be undertaken following the International Union for the Conservation of Nature (IUCN) Guidelines for Reintroductions and Other Conservation Translocations. Translocation of wood ant nests will require the permission of the landowner at the donor and recipient sites.
Where the site is designated, additional consents will be required from the relevant government conservation body: Natural England, Nature Scot, Natural Resources Wales, Council for Nature Conservation & the Countryside (Northern Ireland).
In Scotland the IUCN guidelines have been developed into a code on how to assess and plan conservation translocations in Scotland: Scottish Code for Species Translocations. The code contains forms that must be completed and submitted to Nature Scot for a licence this must be carried out for all species translocations in Scotland. The form allows you to record the translocation process and steps to reduce risk of negative outcomes.
In England, DEFRA have published Reintroductions and other conservation translocations: code and guidance for England (May 2021). This code is based on the IUCN guidelines and is designed to align with the Scottish Code to encourage consistency across the UK.
Health and Safety
Translocating wood ant nests, nest material and ants is stressful for the ants and they will defend themselves by spraying formic acid and biting. When moving large amounts of nest material, the volume of formic acid can be significant and can irritate the skin, eyes and respiratory system.
It is therefore strongly recommended that for any wood ant translocation work and handling of ants and nest material, the following Personal Protective Equipment is used:
Safety goggles
A valved face mask to cover the nose and mouth
Gloves (tough gardening gloves recommended for shovelling and moving nest material)
Sturdy footwear, full length trousers and a top that covers the arms. Trousers should be tucked into long socks or gaiters should be worn.
Translocation Principles
Translocation of wood ant nests must always be the last resort. The ecological mitigation hierarchy should be followed (CIEEM 2018), seeking to avoid any impact on wood ant nests as the priority. If this is not possible, mitigation should be designed to limit impacts on the nest while remaining in situ. Only where avoidance and in situ mitigation are not possible should translocation be considered. The aim should always be to design development, forest plans etc. that complement the natural ecology of wood ants and avoid the need to disturb them.
Reasons for translocation of wood ants
Reason 1:
To prevent loss of wood ant colonies due to a direct threat of extinction (e.g. development, tree removal, irreversible habitat change): this must be a last resort only, as it is best practice to leave wood ant nests in their original location and with sufficient habitat to allow colonies to survive.
Reason 2:
To reintroduce wood ants to historical areas to promote ecological restoration and ecological resilience, capitalising on the role wood ants play as keystone species and ecosystem engineers.
For reason 2 there must be clear justification for re-locating wood ant nests and translocation should only be undertaken if wood ants cannot disperse to these areas on their own, there is historical evidence to suggest that wood ants were present in the past, or that the recipient site is within their native range. There must be clear benefits to moving wood ants, both for the wood ant colony and also the ecology of the recipient site. There should be no sensitive species which could be adversely affected (including existing wood ant colonies) and no factors which would affect long term survival of the wood ant colonies at the new location (i.e. future changes in management).
All methods of translocation need to consider the following principles (adapted from Hughes, 2008):
a. Wood ant nests should always be moved in a way that retains at least the nest layers (even if using the German method see page 13).
b. Recipient sites must be chosen and prepared in advance of the wood ants being moved, with necessary survey work being completed before the translocation (see Appendix 2).
C. Wood ant nests should only be moved during periods of low activity in early spring*. The ambient air temperature should be between 5 and 10°C. Timing must coincide with 2 – 3 days fair weather post-translocation so that the ants have good conditions to rebuild the nest.
d. Wood ants (and Narrow-headed Ant) should never be moved during the winter hibernation period – at this time the ants are deep inside the nest in the underground component where the temperatures are more stable and they can avoid frost. They enter a period of very low activity, utilising fat stores to survive. Excavation of the nest at this time would expose the wood ants to low temperatures which could kill them. Using up their winter stores at this time when they cannot be replenished would cause the overwintering workers and queens to starve.
e. Translocation must consider the distances that nests can be realistically moved, the terrain and whether nests will be moved by hand or in a vehicle. Distances travelled and the time nests are being moved should be kept to an absolute minimum to avoid too much stress on the ants.
f. Translocated nests must be monitored and integrated into long-term management plans to ensure their survival and ability to thrive.
- Key exception to this is translocation of Narrow-headed Ant nests see page 18 and the partial nest method
Stages of translocation
When planning a translocation or reintroduction, a method statement should be compiled, covering all key aspects of the translocation. This should include:
- Reason for translocation/introduction,
- Choice of receptor site(s) based on detailed habitat assessment:
- Habitat suitability study in the season prior to translocation. Receptor sites should aim to be as close to the donor site in habitat structure as possible,
- Identifying precise pinpoint locations for translocated nest(s) at the recipient site(s).
- Description of how the nest translocation will be undertaken practically (preparation at the recipient site; timing; equipment used; nest extraction, transport and installation methods)
- Safeguards to minimise disturbance to other wildlife during the translocation operation,
- Consideration of impacts, and repairing any damage from the translocation operation, at the donor site.
- Post-translocation aftercare (programme of supplementary feeding),
- Post-translocation monitoring (at recipient and donor sites),
- Other relevant information: maps, tracking routes across site(s) for any vehicle movements,
- Health and Safety risk assessment.
Site habitat assessment
- 1) Assessment of donor sites
- Plot the location of all nests requiring translocation and clearly mark them if necessary
- Identify ant species – each species has different habitat preferences (Appendix 1) so it is important to know which species is present. An ecologist with experience of working with ants should be consulted for advice
- Survey and record habitat within 10m and 25m buffer area around each nest requiring translocation (Cathrine 2015a). This will allow the habitat immediately around the nest to be assessed, and also the wider habitat which the wood ants are likely to be foraging in. This detailed assessment is important to ensure a receptor site is chosen that matches the habitat of the donor site as closely as possible. A template for recording this survey information is available in Appendix 2.
If nests or nest material/ants are being translocated to introduce wood ants for reason 2 on page 18, additional factors will need to be considered:
- There must be clear justification for introducing wood ants into habitat where they are currently absent.
- The donor population should be healthy, and removal of individuals or nest material should not have a significant negative effect on the colony’s survival. The exception to this would be where the donor population is at high risk of extinction at its current location and the only option is to move the donor population to a site which would increase their chance of survival.
- Reintroduction of wood ants to a new area will require careful consideration of the quality of habitat at the recipient site and ecological implications of reintroducing wood ants to that habitat, including potential impacts on other species.
2) Assessment of receptor sites
The habitat of the receptor site should match the donor site as far as possible. It is highly recommended that the receptor site is assessed at different times of year to establish effects of drainage and shading. As well as meeting the broader habitat requirements of the wider area, the immediate vicinity of the receptor location should be as similar as possible to the donor site. These should aim to be in sunny, sheltered positions where the ground flora and surrounding trees and shrubs will not shade the nest. Suitable habitat at the receptor site should extend to 20m away from the chosen nest microsite, in order to allow the ants to relocate and bud.
It must be noted that the distance between the donor and receptor sites is also an important consideration and will be an important factor in determining the method of translocation chosen. There are cases of wood ants being transported over huge distances successfully, such as the introduction of Hairy Wood Ant nests from Italy to Canada in the 1970s (Finnegan 1975). However, transportation distances should be kept to a minimum and the time ants are captive kept as short as possible to avoid too much stress on the ants and risk of suffocation and crushing caused by the weight of nest material.
A checklist of factors to note and record at receptor sites is given in Appendix 2.
Deciding on method of translocation
Reason 1:
Translocation of nests under direct threat of destruction
Aim: To translocate all nests and as much of the nest material as possible. It is impossible to collect all of the individual ants and inevitably some will be left behind.
Objective: To retain the local population and its genetics by establishing viable nests in alternative locations — this is done by capturing queens with enough of a workforce to support them.
Methods: There are two methods that are likely to be used, both of which aim to collect as much of the original nest material as possible.
Method I — GERMAN METHOD
Method 2 — WHOLE NEST EXCAVATION METHOD
See Appendix 3 for the pros and cons of each of the current documented translocation methods for ants. A flow chart is provided in Appendix 4 to assist in deciding between translocation methods.
Principles common to both methods:
- Translocation should be carried out in the morning when it is cooler and ants are less likely to be highly active and foraging away from the nest
- Choice of receptor site for the nest must be made prior to translocation receptor sites for translocated nests should be carefully selected to be as similar to the donor site as possible and must be of sunny, sheltered locations that are south or south-east facing. In advance of the translocation, the individual receptor sites will require some preparation to accept the nest material and accessible bare soil for the ants to tunnel into. Receptor site preparation involves scraping an area of the ground surface to remove surface vegetation, approximate to the size of the nest being moved. The diameter and depth of the depression should reflect the dimensions of the nest being moved. The excavated material can be mounded up on the northern side of the depression and may help to provide additional structure and warmth for the nest (Jukes & Price 2016). Some translocation methods where nest structure isn’t retained involve placing tree brash and branches in the created hollow to provide “scaffolding” for the ants to build around (Jukes & Price 2016, Attewell 2020, Attewell 2021).
- When moving multiple nests, sufficient space should be given to each nest there should only be one nest every 100m where nests are unrelated. This will give individual nests room to relocate and expand and prevents conflict between nests, if nests are not related to each other. Where nests are known to be related to one another (i.e. form part of a polydomous colony) then distance between nests can be much smaller, e.g. 15 – 20m (Jukes & Price 2016).
- Supplementary feeding post translocation is required to provide an immediate energy source to the ants until they can establish new foraging routes. Supplementary feed can take the form of chopped fruit (apple/pear), a home-made mash (made of bread, honey, raw egg and water), honeybee fondant, or purpose made ant gels*.
* An example of ant gel can be found here
GERMAN METHOD
This method is based on a translation of a method by the Deutsche Ameisenschutzwarte (German Office for the Protection of Ants). It involves scooping up the nest material into containers (such as hessian sacks or large plastic barrels) which are then emptied at the donor site.
Timing:
- Aim to coincide with the swarming behaviour of the ants in early spring, when they start to become active after hibernation. At this time the ants will be higher up within the mound; on top of it or in the topmost layer of soil around the mound. Observational visits to the nests in advance of the translocation will help to determine the activity level of the ants. It is important that queens are captured during the translocation and at this time of the year queens are usually above ground inside the mound and easier to locate.
- Avoid summer months when workers are active and dispersed away from the nest this risks losing significant numbers of workers. Translocations should only be undertaken at this time of year as a last resort.
- Avoid late summer and autumn as this is when the colony activity starts to slow down and if moved during this period ants may not have enough time to repair the nest and restore foraging routes before winter. Translocations should only be undertaken at this time of year as a last resort.
- Should avoid the hibernation period (November-March) at all costs
- Should be carried out in the morning and completed by midday this way the ants will be cold and slow and mostly situated within the mound. Choose a day with good settled weather (no frost, warm and dry, between 5 and 10°C). The day of translocation should be followed by 2 – 3 days of settled weather so that the ants can repair the nest and develop foraging routes.
GERMAN METHOD – continued
Equipment:
- Minimum of 3 people, more depending on size of nest(s).
- Wide, flat, coal-type shovels (potentially less damaging than sharp digging spades) for the thatch, and conventional spades for the subterranean parts of the nest.
- Breathable containers for carrying the ants that protect them from direct sunlight and absorb the formic acid they spray in defence. Old-style hessian potato sacks made from natural fibres work well. A recommended size is 90cm x 60cm (larger sacks may be too heavy to lift when full) (Jukes & Price 2016). Large plastic barrels have also been used successfully and reduces the number of workers lost or escaping during transport (Phil Attewell, pers. comm, and also German Office for Protection of Ants).
- A pen to write the nest number on to the pertaining sack or barrel.
- String or other cord to tie up the sacks (or if using large plastic barrels, FluonTM paint painted below the top of the container can be used to prevent ants from escaping).
- A means of transporting the containers with nest material from donor site to receptor site (wheelbarrow, pick-up truck etc. depending on distances involved and terrain).
GERMAN METHOD – continued
Procedure:
- Prepare the receptor site.
- Working in pairs, one person holding open the container, one person shovelling the nest, shovel up as much of the massed ants and nest material as possible, in as few scoops as possible to reduce time taken and stress caused to the ants. Depending on the size of the nest, this will likely require several sacks or barrels. Fill containers only half full to avoid crushing at the bottom, adding small branches and twigs whilst the bag is being filled with nest material to help alleviate pressure from the weight of material. Tie up each container as quickly as possible after filling.
- Saws may be required where there are roots embedded in the nest structure.
- Excavate the nest as far as the soil structure will allow, until there are no more signs of ant tunnels. Take care to look for queens (see Appendix 6) (it’s worth having an assistant who is not shovelling that can focus on doing this) which must be carefully collected by hand or with a small container or into pots for release at the receptor site.
- Label the containers in the order that they are excavated so that they can be emptied at the receptor site in the correct order (deepest layers first, working up towards the topmost thatch).
- Transport the containers to the receptor site – the transport route should be planned in advance so that it can be kept as short as possible and avoid bumpy terrain. Depending on the distance between donor site and receptor site this could be done in a wheelbarrow for example or in the back of a pick-up truck, but whichever is chosen the speed of transport should be slow and careful to avoid too much rough handling of the containers. If using sacks, these should be loaded flat on their sides to reduce compression pressure on the ants. Aim to keep the time that the ants are held in the transportation sacks as short as possible.
- At the receptor sites, open the containers and carefully tip the material over the prepared hollow, in the correct order to maintain the layers of material. If using hessian sacks, each sack should be cut into two or three pieces and placed with the nest material – this will ensure any ants and small invertebrates that live inside the nest are retained. The hessian sack will contribute to the nest framework and will eventually rot away.
- The ants should be provided with supplementary food immediately after translocation – this sustains the workers while they establish new foraging routes. Record and photograph the new location of the nest. It is likely that the ants will re-assemble the nest in a slightly different position, a short distance away, or split into multiple mounds (if the original nest was polygynous).
- If the nest is to be situated within proximity of construction work, the nest should be marked and protective fencing or a barrier erected to prevent nest being damaged.
Follow-up care:
- Check the original donor site for three days after the translocation for any remaining ants collect these and move them to the new location. Check after three months for any signs of re-establishment at the donor site*.
- Continue to replenish and provide supplementary food every few days for at least two weeks.
- Remove any protective fencing, if present, once this is no longer needed.
- If a queen and enough workers are left behind at the original donor site, a nest may re-establish at the original site. This is why it is important to excavate as much nest material and as many ants as possible during the translocation. It is important to check the donor sites after the translocation work — ants left behind may re-establish a nest or wood ants from nearby may also colonise the area. There may be a need to carry out a second translocation if there is a sufficient time delay for wood ants to establish a new nest between the first translocation and site clearance and this should be factored into project plans.
WHOLE NEST EXCAVATION METHOD
Instead of collecting into sacks, the principle is to collect the nest as a whole, as far as is possible and move it as a single mass, retaining structure. If an excavator is already on site, this may be a cost and time efficient approach.
Timing: As German method.
Equipment: An excavator with a digging bucket exceeding the size of the nest being moved should be used so that it can excavate the nest in a single scoop. Some hand excavation may still be required alongside a mechanical excavation.
Procedure:
- Prepare the receptor site.
- Clear the route between the nest and the receptor site so there are no hazards or obstacles (which could increase vibration and damage nest architecture).
- If the nest is constructed around a feature, such as a dead tree or stump, it may be necessary to undertake some preparatory hand digging and sawing of roots before using an excavator.
- Excavate using excavator with a digging bucket attachment exceeding the size of the nest being moved. Aim to excavate the entire nest and any feature it may be built around in a single scoop.
- Move nest as slowly and steadily as possible (around 2.5 mph if using an excavator).
- Some hand excavation (as German method) and collection of nest material and ants into containers may be required, if the excavation with the digger does not manage to capture the entire nest.
- Deposit nest in receptor site hollow gently, at same orientation as at donor site.
- Provide supplementary food (see German method).
- Mark the nest and provide protective fencing as required.
WHOLE NEST EXCAVATION METHOD – continued
Follow-up care:
- Check the original donor site for three days after the translocation for any remaining ants collect these and move them to the new location. Check after three months for any signs of re-establishment at the donor site (see footnote on page 15).
- Continue to replenish and provide supplementary food every few days for at least two weeks.
- Remove any protective fencing, if present, once this is no longer needed.
It is not uncommon when using the above methods for wood ants to re-locate their nests shortly after translocation. The ants may find a more suitable location for the nest a short distance away and re-build it there, or the nest may re-form as two mounds rather than one. Nest mounds may relocate several times following translocation before the eventually “settle” (Andy Jukes, Pers. Comm.) therefore it is important that there is suitable habitat within 20m of the chosen micro-site to give the ants space to move about and relocate if they need to.
Tree spade
There is no record of a tree spade being used to translocate wood ant nests or nests of Narrow-headed Ant, though there has been success in using this method to relocate nests of Yellow-Meadow Ants (Lasius flavus) (King & Balfour 2019) which is a subterranean species and creates hills of excavated soil. There is potential that this could be used to translocate wood ant nests under the right conditions; large machinery is obviously required so access needs to be considered. If this type of machinery is already on site for other purposes it might present a cost-effective option.
King & Balfour (2019) used a tree spade mounted on a compact loader, with a scoop diameter of 1.1 m and produced a conical soil lump 0.85 cm deep. The translocated ant-hills of Yellow-Meadow Ants were up to 0.7 m in diameter. The nests were transported I km from the donor site to the recipient site and the compact loader was able to travel at over 20 km/hr which reduced the time taken during translocation. All five of the nests that were translocated were still active and intact 17 months after the translocation.
A variety of spades, grabs and boxes can be mounted on compact loaders offering a variety of scoop sizes and shapes. A four-wheel drive compact loader provides manoeuvrability whilst minimising ground disturbance.
As with the above mechanical excavation method, some hand excavation and collection of nest material and ants into containers is likely to be required, if the nest is very large and the excavation does not manage to capture the entire nest.
The procedure with regards to timing, preparation of receptor site, supplementary feeding etc. would still apply see German Method and Whole Nest Methods.
Reasons 2:
Translocation to increase resilience or for ecological restoration
Because this type of translocation has the aim of moving nests in