Winter Ecology Surveys

Winter Ecology Surveys

Contrary to popular belief, ecological work doesn’t grind to a halt in winter. In fact, the winter ecology survey season provides an opportune time to undertake certain types of ecological surveys and to lay the foundations for the following main survey season; thereby helping to avoid costly delays, last minute design changes and programming complications.

In this post, we take a look at some of the surveys that can be carried out at this time of year.

Which ecology surveys can be completed in winter?

Here are a few of the surveys that can be completed in winter – some can only be undertaken at this time of year, and some, like Preliminary Ecological Appraisals and Preliminary Roost Assessments can be undertaken throughout the year.

Our handy ecology survey calendar can be downloaded here.


Whilst the main active season for bats is now over until spring, winter provides the opportunity to undertake hibernation surveys. Bats use multiple sites throughout the year for roosting purposes. In winter, bats enter an extended period of torpor and to facilitate this, the qualities of the roost sites needed for hibernation, often differ from bat’s requirements during the active season.

In addition to hibernation surveys, an absence of leaves on trees exposes trunks and branches to the naked eye, allowing effective scoping surveys of trees to be undertaken in order to identify potential roost features. Preliminary Roost Assessments (PRA) can also be undertaken in winter (they are not season dependant at all). This information can then be used to influence scheme design and programming of further survey work in spring.

Otter surveys

Vegetation dieback over winter often leads to improved visibility of river banks and marginal habitat. This in turn makes it easier to identify the field signs of otter – feeding remains, holts and spraints can all become more prominent in the landscape at this time of year.

Wintering bird surveys

As the name suggests, wintering bird surveys can only be undertaken over the winter months. The UK provides a refuge for many migratory species of birds over the winter period, which are not present during the spring and summer months.


Although dormice themselves find a cosy spot to hibernate over winter, the cold season is a good time to undertake nut searches. Their distinctive way of gnawing hazelnuts is a great way to establish dormouse presence.


Again, due to the vegetation dying back over winter, it can be easier to identify field signs of badger activity, such as sett entrances and latrines. As with other surveys, identifying field signs at an early stage in a project means that further surveys and mitigation can be woven into the project design at an opportune time.

Preliminary Ecological Appraisal/scoping surveys

Phase 1 surveys/Preliminary Ecological Appraisals can be undertaken at any time of year. Carrying out an initial assessment over the winter months ensures that pertinent features can be identified in advance of the main survey season, allowing for further survey work to be programmed in accordingly, well in advance.


BREEAM assessments are also able to be commissioned over the winter months. Early ecology engagement is key to maximising land use and ecology credits, particularly with the new version of BREEAM UK New Construction, which was released in 2018.

So to conclude, as with most things ecological, forward planning is key. Getting the heads-up in plenty of time when it comes to surveys that may be needed in the spring and summer months supports robust project management and a smoother assessment process.

Unlike a number of our protected species, our ecologists definitely won’t be hibernating over winter, so do get in touch to discuss your requirements.