- Fleas and Keds:
Fleas and Keds (small, wingless, blood-sucking flies which live amongst feathers on birds and fur on mammals) must be considered as special cases for capture techniques as they do not live in 'normal' habitats but use mammals and birds bodies as their living environment. The person wishing to collect and/or record these insects needs to combine the expertise and skills of a mammologist, an ornithologist and an ecologist if they are to maximise their collecting opportunities.
It is probably wise to include a caveat at this juncture. Handling of many live mammals and birds in Britain requires a Licence following the implementation of various Wildlife Acts (e.g. a licence is required to handle bats, badgers and hedgehogs). Collectors should act accordingly and furnish themselves with the necessary legal documents and verification before embarking upon projects requiring live wild animals to be handled and/or trapped. Initial approaches should be made to your local/regional English Nature department.
Collection of these insects from bodies is often the easiest, and sometimes the only, way of obtaining the necessary specimens from various mammals, including humans, although nest collection can often be the more productive for birds (see previous section). Bodies may be obtained alive by various trapping techniques (e.g. Longworth trap) or dead by shooting or as car accidents on the road. Bats must be either hand-gathered at their roosts or mist-net trapped. Fleas and keds may be collected from the animals/bodies gathered in a number of ways depending upon the size of the host animal. The following methods may be employed:
- Large bodied animals (e.g. badgers, deer, etc.) should firstly be visually examined and specimens of the fleas, mites, ticks and keds manually removed and tubed in glass vials. Following this examination they should be hung up over a wide pan of water in which a few drops of detergent have been dissolved. As the various insects react to the cooling of the animals body they will attempt to hop or drop off and will land in the water. The detergent will reduce the effect of the surface tension and consequently the insects will sink to be collected later in the day. This type of trap must be visited daily and all insects removed and placed in a 70% solution of alcohol; this being a preservative. Industrial Methanol is the best form of alcohol to use being readily available from chemical firms and not requiring an Excise Licence as is the case with Ethanol. Ethanol can be used but is far too expensive though if one is out in the wilds with no access to anything else vodka or whisky may be employed. Iso-Propyl Alcohol (IPA) can be used if Methanol is not available - this is even available at Boot's the chemists.
- Animals with medium sized bodies such as squirrels, rabbits, rats and hedgehogs, should be placed into a polythene bag with a little anaesthetic. After a few minutes they can be searched over a large sheet of white paper and all the ectoparasites, including ticks, fleas, mites, beetles, lice, flies, etc. Can be collected and tubed in 70% alcohol as in the paragraph above. If it is intended that the host animal be kept alive for later release back into the wild the anaesthetic used should be ether and a glass container substituted for the polythene bag. Searching for ectoparasites should begin immediately, the animal becomes unconscious and should be conducted with the animal out of the glass container and away from the anaesthetic.
- Small bodied animals such as mice, voles and shrews, are most easily obtained via the use of one of the forms of live-traps on the market (e.g. Longworth traps) - though it must be noted that these traps are both bulky and expensive and the placement of large numbers at a site represents a distinct capital expenditure and a potentially large loss should the site be prone to vandalism. If they are to be released back into the wild it must be noted that only very light anaesthesia can be tolerated by these small animals. Another method is to hold the unanaesthetised animal, by the scruff of its neck, over a largish piece of white lint. The insects can be blown out of the fur, or will hop out following disturbance, and will become entangled in the fibres of the lint from whence they can be manually collected into tubes of 70% alcohol.
Where animals are creating an infestation or populations are very high then a case may be made for the use of 'nipper' traps which are small, light, and very cheap. Losses resulting from a short survey using these traps will have negligible effect on normal populations but there use may be contra-indicated where populations are smaller or genetically restricted (i.e. small islands, or small, specialised and restricted populations). The equipment needed to conduct a survey using 'nipper' traps is as follows:
- the 'nipper' traps themselves which can be obtained from most
chandler's or iron-mongers;
The traps, which should have been set very fine, should be visited on a regular basis, at least twice per day, early and late. When a trap is found to contain a body an envelope should be placed on the ground next to the dead animal. The trap should be gently lifted, ungentle handling will result in the insect populations 'abandoning ship', and both body and trap should be slid rapidly into the envelope. The envelope is then rolled around the body and the whole package placed into the tin with some of the anaesthetic/killing agent. Please note: all of the anaesthetics, killing agents, knock-down agents used are to varying extents poisonous and/or carcinogenic - do not breathe the fumes or get the agent on your bare skin. The lid should be replaced on the tin as soon as the package has been placed inside. The trap should be replaced, re-baited and re-set and the tour of the trap-line re-commenced. By the time the tour of the trap-line has been completed and the collector has reached home all of the ectoparasites on the bodies inside the tin will be dead. The bodies and the envelopes should be examined one by one and all the parasites collected into tubes of 70% alcohol. Some of the insects will often have crawled into the corners, seams or folds of the envelope which may be torn part in the search for these strays. Some collectors use cloth bags but, because of re-use, these introduce a considerable risk of a parasite being overlooked and then being attributed to a different site and host at a later date. This, obviously, would result in incorrect and inaccurate host/parasite records and the single use of envelopes eliminates this potential error.
- Bat fleas and other parasites are usually collected from living hosts as bat populations are often small and can rarely withstand depletions of any form. The method used to obtain the parasites involves the use of a 2lb/1 kilogram jam jar, a piece of blotting paper, and ether or ethyl-acetate. Note: to use this technique you will require a licence to handle bats for research purposes. The bat is placed into the jam jar and a small piece of blotting paper wetted with just three drops of ether is added (Note: do not use chloroform - the bat will not recover from this chemical). The jar should now be closed off with the palm of the hand. Immediately the bat becomes unconscious it should be tipped out of the jar and manually searched for various ectoparasites. The bat will normally recover within a few minutes and will be ready for re-release to the wild within ten minutes. Bat droppings gathered from under bat roosts should be collected and placed in sealed tins or in large glass jars. Fleas and other insects, including beetles, can often be reared from this guano deposit.
- Live birds should be examined via the use of the Williamson apparatus (Williamson, 1954). Unfortunately this apparatus is expensive to purchase and is rather fragile in the field. A home-made version which works just as well can be constructed from a 2lb/1 Kilogram jam jar and a piece of oil-cloth with a small hole cut in the centre. Once the bird(s) have been caught, either by mist-netting, rocket netting or hand-netting, some anaesthetic, preferably ether or ethyl-acetate, is placed in the jam jar and the bird's head is put through the small hole in the piece of oil-cloth. The bird's body is lowered into the jam jar and the oil cloth closes off the top of the jar and prevents the fumes of the anaesthetic from reaching the bird's head. The bird will flutter its wings inside the jar and this, along with the knock-down capabilities of the anaesthetic, helps to anaesthetise the parasites amongst its feathers. The parasites will fall off the bird and can be collected into tubes of 70% alcohol once the bird has been released. It is essential that the jar is cleaned thoroughly between birds in order to ensure that parasites recorded as coming from a particular bird are accurately attributed. Failure to follow this regime in a strict manner could produce false records and must be construed as invalidating all data from such an exercise.
All ectoparasites collected from individual mammal, reptile and bird bodies may be collected into one tube of alcohol but such tubes should never contain specimens from more than the one single individual host animal. It is essential that each tube is labelled with, at least, the minimum of required data. These items of information being:
- the identity of the host species;
All of the above information should be written in Indian ink (Rotring Mapping Ink) or pencil on a slip of paper or thin card and the label placed inside the tube with the specimens. If any collecting is undertaken in mountainous districts then the altitude of the collecting site (not the camp-site) is useful. Other information on observed biology etc. can prove useful but the above should always be included and should be viewed as the minimum acceptable for the specimens to be worthwhile in a scientific context.