Survey Calendar

Planning ecology surveys into your project

Since wildlife species are active at different times of the year, some ecology surveys may only be suitable within specific months of the year. This calendar has been created for use as a basic guideline for planning purposes. For more detailed information, speak to one of our experienced ecologists about your site.

In most cases, a Phase I survey is first required, after which your ecologist will recommend any further surveys.

Download survey calendar

Phase I habitat survey

An Extended Phase I Habitat Survey or Preliminary Ecological Assessment is the first step in assessing the potential ecological effects (or lack of) for a proposed development. It enables us to assess the ecological value of the site, classify habitats and establishes whether further surveys are required to satisfy relevant legislation and planning policy. This survey may be done at any time of year, though summer months allows for a more complete vegetation species list.

Vegetation survey

The NVC vegetation survey method classifies the full suite of species within a vegetation type. The habitat communities on site are coded and mapped out. Any communities of biological interest are identified. This survey may require several visits throughout the active season to identify a full range of species.

Bat survey

Phase II bat emergence survey

A building can be inspected for bats any time of year. Phase II summer roost surveys involve between one and three emergence and/or re-entry surveys. They must be undertaken during the active survey season (May - September) and spaced out by at least two weeks. If a structure has high potential or a confirmed roost, two of the three surveys must be carried out by the end of August.

Phase II bat activity survey

Bat activity surveys are used to establish important commuting or foraging routes or areas of habitat used by bats. This may require several visits throughout the survey season.

Reptile survey

Reptile surveys must be completed during periods of suitable weather. The ecologist will distribute reptile refugia and subsequently search them for reptiles seven times during the suitable season. Reptile surveys are best carried out during spring and late summer.

Newt survey

A Habitat Suitability Index (HSI) assessment may be carried out at any time of year to determine if it it potential habitat for Great Crested Newts (GCN).

eDNA analysis

This method searches for the DNA of GCN in water samples collected on site. The DNA only lasts approximately 20 days in the water, therefore water samples must be taken in the appropriate season to determine presence or absence. If the result is positive, Phase II surveys are still required.

Phase II GCN survey

These newt surveys are seasonal and must be done in the GCN breeding season. It involves four to six separate site visits with at least two surveys in peak season between March and June, depending on weather and conditions.

Dormouse survey

A Phase II dormouse survey is undertaken by setting out nest tubes and/or boxes in woodland and hedgerows. The tubes/boxes are checked many times between April and November to search for evidence of dormice. It is best to plan these surveys in early to ensure they can be completed within one season.

Bird survey

Breeding bird survey

A breeding bird survey will determine if rare birds are using the site and which features are most important. It involves several dawn site visits during the spring when the majority of breeding bird species can be found.

Nesting bird survey

If it is not possible to cut vegetation outside of bird nesting season, a nesting survey must be carried out to make sure no active nests will be disturbed. If an active nest is found, it must be left in place with a 5m boundary until it is considered no longer active by an ecologist.

Wintering bird survey

A wintering bird survey may be required if it is determined the site has potential for certain species to be using the site during winter months. This survey involves several site visits during the winter months.

Barn Owl survey

Most Barn Owl nests or roosts can be found during a detailed search of the premise as part of a Phase I survey or separately at any time of the year.

However, nesting surveys (to determine if it is an active nest) can only be undertaken during the nesting season, considered to be March to June. Wintering surveys can also be undertaken during November to February.

Badger survey

A search may be undertaken at any time of year for badger setts on site, although it may be more difficult with dense vegetation. Phase II badger surveys using a camera trap may be required to determine if a sett is active and what type of sett it is. These surveys may be undertaken at any time of year, but February-April and October-November are the most suitable times.

Invertebrate survey

An inventory will be taken of aquatic and/or terrestrial invertebrate species. The most optimal time of year is dependent on site conditions and the habitat. This survey may require several site visits throughout the active survey season.

Otter survey

An otter survey may be undertaken at any time of year. It may involve several site visits throughout the year to cover different time periods. There must be at least five days without rain preceding the survey so that evidence is not washed away.

Water Vole survey

Phase II Water Vole surveys may be carried out from April to early autumn to search for evidence of their presence. Surveys should not be carried out if it has recently rained as evidence can be lost during this time.

White-clawed Crayfish survey

eDNA analysis

This method searches for the DNA of White-clawed Crayfish in water samples collected on site. The water samples must be taken in the appropriate season to determine presence or absence. If the result is positive, Phase II surveys are still required for a European Protected Species Licence.

Phase II White-clawed Crayfish survey

These surveys must be undertaken by a licensed surveyor. Surveys have a limited season and are best undertaken in July to September after they have released their young

About us

Providing quality ecology services across southern England and beyond since 1999.

At Ecosupport we complete comprehensive ecological reports for Preliminary Ecological Appraisals, Phase I Surveys, BREEAM, NVC Vegetation and Hedgerows and Phase II Surveys for protected species such as bats, reptiles, dormice, GCN, birds and badgers. We work directly with our clients to deliver pragmatic results and can implement any required mitigation or habitat restoration to see through your ecological needs from start to finish. Our large network of ecologists enables us to offer all our services all across the UK.

Ecosupport is SSIP-certified through SMAS Ltd.


Ecosupport - Head Office
K4 Keppel, Daedalus Park
Daedalus Drive, Lee-on-the-Solent
PO13 9FX


01329 832 841

Telephone (International)

+44 1329 832 841