Recording & Support -
Recording Methods
Field Surveying Techniques
1. Introduction
These pages are designed to provide you with an insight into surveying methods used by recorders and recording groups. They are not designed to be comprehensive guidelines, but simply to give you a flavour of the variety of survey techniques which are employed by professionals and sometimes by volunteers, in order to generate records and monitor species populations.All of the techniques mentioned require some experience, if you're interested in learning any of the techniques mentioned then we would recommend either getting in touch with us or directly with the appropriate local recording group for advice. Most groups go out to do survey work and many will happily welcome along a new member.
If you'd like more information of survey methods and techniques please get in touch with us and we can point you to some useful organisations and literature.
2. Mammals
Surveying for mammals can be conducted in various ways using numerous disciplines.Field Observations, tracks and signs
Water
Vole latrine (© S. Smith)Live (humane) Trapping
Longworth
small mammal trap (© L Manning)Nestboxes
However not all small mammals can be monitored in this way, dormice require a different approach, as well as a licence. Nest boxes can be numbered and then regularly checked for dormice with their gender, weight and breeding conditions all noted.Hair Tubes
Small mammals can also be surveying using less intrusive techniques such as hair tubes, these tubes are constructed to ensure that small amounts of hair are caught, the hair can then show the presence of an animal and can also be used to identify the species. This is increasingly being used to monitor dormice and red squirrels as it is inexpensive but effective.Line Transects
The use of line transects is also an important survey method as they can be employed alongside other techniques. Line transects require that a surveyor follows a predetermined line which should cross the habitat to be surveyed. Many trapping studies use this method to ensure that the sampling method is seen to be unbiased. It is best used in situations where a population is considered to be sparse in a large area as a transect would offer the best chance of finding field signs.Photography
A common technique used for marine mammal surveys includes photographic identification; photographs of the animals allow surveyors to accurately monitor that individual's behaviour and activity without being intrusive. Aerial counts are also used to monitor marine mammals and have been commonly used to conduct seal colony counts.3. Bats
As a flying mammal species, bats can prove to be very difficult to survey in general. They can require the use of specific equipment and normally an excellent knowledge of species-specific frequencies, behaviour, diet and habitat.Bat detector
One of the most popular surveying techniques involves the use of a bat detector; a detector is able to collect and convert the echolocation signals used by bats to navigate around so that they become audible to humans. A top of the range bat detector can detect all echolocation frequencies from all bat species present in the UK. The use of a bat detector also relies on the user having a good working knowledge of the unique frequencies that each individual species uses to echolocate, though now it is also possible to record the audio and use computer software to analyse the results. Other methods include colony counts; this requires the surveyor to have knowledge of where a roost site is situated and then count all bats emerging from the roost. Any methods involving the catching or handling of bats requires a licensed surveyor and is therefore are not regularly used. There are also some species specific survey methods, for example a waterway survey involves the use of a bat detector along a linear water way such as a river and focuses on Daubenton's bat as they tend to search for invertebrates across the water.Terrestrial Invertebrates
Invertebrate surveying requires excellent identification skills as many invertebrates appear to be look very similar. For larger invertebrates such as butterflies it is possible for sightings to be considered a reliable survey method however for small invertebrates such as mosquitoes more direct techniques are required as identification is more complicated.Beating
A very basic but effective way of surveying invertebrates in trees and bushes is to use a "beating" method. This involves the shaking or beating of the branches of a tree or shrub to dislodge the insects, which then fall into a collecting tray or specially designed collecting cloth. These cloths are often white to help show up the species collected. You can then trap in a viewing tube the species you'd like to take a closer look at. For invertebrates higher in the tree canopy a technique known as fogging is used, this involves the use of pesticides that are blown or fogged into the tree canopy which then dislodge the invertebrates into a collecting area below. However this method requires a great deal of knowledge and, as pesticides are being used, a health and safety license is required.Sweep Netting
In habitats such as meadows the best method of surveying invertebrates is to conduct sweep netting. Sweep netting requires the surveyor to sweep a large net backwards and forwards across a predetermined area to collect samples of invertebrates such as flies and bugs. There are different designs of net available and the gauze size reflects which invertebrates are being surveyed for, for example a thinner gauzed net will catch more flying insects and a thicker gauze will collect larger insects from more dense vegetative areas.Pooter
Equipment such as a pooter is ideal for capturing small insects; the pooter has 2 tubes which feed into a collecting jar. The surveyor sucks through one tube (which has a fine mesh at one end). This sucks the creature through the second straw and into the jar where it can be viewed safely.Trapping
For invertebrates such as beetles and spiders, which live on the surface of the ground, trapping using a pitfall trap produces the best results. These traps are placed into the soil so that they are flush with the ground level, the invertebrate will then fall into the trap as it walks across the ground. These traps, checking the traps regularly is necessary.Transects
Used often to study butterfliesLight trapping
Primarily used to survey for moths, light trapping is a successful way of safely trapping and hopefully identifying moths. This is one of the most successful techniques and will give you a good idea of what moths can be found in your local area. You can create your own light trap using a white sheet spread out with a light above or in front of it. An ordinary light bulb will attract some species, but specialist mercury vapour bulbs have been proven more effective. However if you're just starting why not leave your outside light on in the evening and then go out and see what moths you've attracted. The Robinson light trap is generally considered the best trap to use in gardens.5. Aquatic invertebrates
Large aquatic invertebrates that live on the surface of ponds can sometimes be easily identified by sight but this will depend on the clarity of the water.Pond dipping/netting
Pond netting is a tried and tested method of collecting aquatic invertebrates in large numbers, the invertebrates can then be placed into a collecting tray. However the technique of this method can differ drastically as surveyors may net at different speeds and different levels.6. Newts
Torching
One of the best ways of surveying for newts is to use a method called Torching, usually conducted at dusk or sometime during the night. Species such as great crested newts are most active during the night; light from a powerful torch illuminates the animals making them easier to count.Netting
Netting for newts is also a useful surveying technique - remember you need a licence to hold great-crested newts. Creatures can be turned out into a suitable container to be counted and sexed before being returned to the pond.Egg Counts
Observing newt eggs is also a useful survey method. Conducted at the right time of year you can observe eggs which can be identified to species levelFrogs and Toads
These species are best surveyed during the breeding season where large numbers congregate in ponds at the same time. This will give you a good picture of the health of a local population.You can also look for spawn, or tadpoles can be surveyed for by sight or using a fine mesh net.
7. Reptiles
ACOs Artificial Cover Objects (Refugia)
This is a simple method for recording reptiles. ACOs are often made of roofing tin or felt and are laid out in areas of suitable habitat with the landowner's permission. They work by heating up the ground and they can keep it warm for a while even if the weather turns wet or cool. Also they provide shelter which species like.ACOs generally have a minimum size which is believed to be effective. Surveyors mark the locations of Refugia (often laid out during the winter months) and can go back a re-check ACOs during the spring and summer. Amphibians, particularly toads will use ACOs as well as small mammals and invertebrates. So they make a good recording tool all round. Surveyors have to be careful when lifting ACOs for health and safety reasons.
8. Plants:
The easiest way to survey plants is during the flowering season, as the flowers make identification much more straightforward.There are many techniques for surveying for plants. The obvious one would be field observations. Making casual observations of plants you see.
Quadrat Surveys
Used to measure abundance of vegetation, over a given area which can then be extrapolated to cover the whole site.Trees
Veteran Trees
Veteran trees are important as they can support incredible biodiversity. They are also part of our natural heritage and some old trees such as Yews are historically and socially significant.The Records Centre is currently involved in collating information for veteran trees in Kent. This is forming part of a regional study of veteran trees with the hope to being able collect records on these trees in the future. Recording all trees but particularly veteran trees involves considering the trees setting, species, size of girth, the form the tree takes, e.g. pollard, coppice etc, whether it is alive or dead and whether it has holes as well. All of these factors will affect the species associated with the tree.
The Records Centre has veteran tree recording forms, so if you'd like to contribute veteran tree information for your area, or you know of a veteran tree then please get in touch.
