CLIMB-&-INSPECT AERIAL TREE SURVEYS: BATS & BARN OWLS
Many protected species use trees as a place of shelter, to nest or roost. Most notably are bats and barn owls. Accessing trees to search for protected species can be difficult due to the location, height and positioning of the trees within the landscape. It may also be very tricky to reach any potential features that house these species.
Using aerial rope techniques, we specialise in climb & inspect aerial tree surveys to access and survey the trees from the ground to the canopy. This is great for looking for evidence of bats, barn owls, dormice and nesting birds.
If there is potential for badgers or a badger sett to be affected by a proposed development, a survey is needed to identify the extent to which badgers use a particular area to establish active setts, foraging areas and territory. Badger surveys can be conducted throughout the year however optimal months are from February to April and September to November. Although setts can still be surveyed they should not be disturbed, closed or removed between December and the end of June as the young will still be dependant upon the sow at this time.
The loss of foraging and breeding habitat has become a problem for barn owls due to intensive farming methods and conversions of suitable buildings. Where there is potential for barn owls to be affected by a proposed development either in buildings or trees, surveys are required to establish if barn owls are using the site and for what purpose. Even if barn owls are not present at the time of survey, indirect signs e.g pellets, will provide evidence of use.
Bats are highly mobile animals and will regularly move between roosts over the course of the summer, and even through their winter hibernation period. In order to determine the presence or absence of bats, several techniques may need to be implemented at appropriate times of the year. An initial desk based study is recommended to acquire historical records of bats and bat roosts in the local area, and to identify any potentially suitable habitat or statutory designated sites. This information will inform the survey technique and survey effort.
An initial bird survey will be carried out to assess how suitable the site is for breeding and wintering birds, during this time bird sightings will be recorded to get an overall sense of the site. A special emphasis is placed on the areas suitability for Schedule 1 and UKBAP species. A report which is suitable for planning permission will be published; this will identify potential impacts on protected species that may occur, suggest mitigation measures and any further work required. If evidence of rare birds or bird breeding habitat is found, further surveys may be required.
Dormice have been found in small woods (as little as 2 hectares) where other suitable habitat is available. Certain factors affecting the probability of dormice will indicate their likely presence, however, in areas of woody habitat (even apparently unsuitable habitat including plantations, hedgerow and scrub) the presence of dormice should be assumed and surveys should be undertaken to determine their presence or likely absence. As dormice are secretive animals, finding indirect evidence of dormice is the most common survey technique.
GREAT CRESTED NEWTS
Great crested newts spend much of the year on land and can be difficult to detect during this period. Survey effort is therefore concentrated in potential breeding ponds when they congregate in the spring and summer to reproduce. Due to the protection afforded to great crested newts, all survey techniques must be conducted by a licensed individual.
Great crested newts are primarily nocturnal, therefore it is necessary to survey at night as well as the day, and during the breeding period of mid March to mid June. Four visits are required to determine presence or absence of the species , or six visits to estimate population size. In either case, 50% of the visits must take place between mid April and mid May.
Otters are illusive animals and can be difficult to observe directly especially due to their nocturnal habits. Otter surveys are best carried out by searching for indirect evidence of their presence. Surveys are best carried out when herbaceous vegetation is less dense i.e. autumn and winter month. Suitable otter habitat may vary considerably, however it appears that adequate quantities of food appear to be the most critical factor. Potential habitat should be walked and features observed e.g. under bridges, old trees, mounds etc which may act as potential holts, couches or sprainting sites.
Common terrestrial species such as adders, grass snakes, slow worms and common lizards are the most likely species to be affected during a development. Reptile surveys are seasonally constrained and should be conducted between March and October (weather dependant) but the peak months are April, May and October.
At least 7 surveys should be carried out during appropriate times of year and during suitable weather conditions to establish presence / likely absence of reptiles. If more detailed population studies are required this may take up to 20 surveys over the course of a season.
Water voles are secretive animals and direct observations are made difficult due to their shy lifestyle. Surveys are best conducted by searching for characteristic field signs along suitable habitat i.e. steep river banks with lush herbaceous vegetation and clean, stable water levels.