Roost Counts

Help count hundreds of bats!   No charge to participate, suitable for all.

Soprano Pipistrelle Maternity Roost – EWT Hanningfield Visitor Centre, near Billericay  

The main roost is in the visitor centre roof (behind), but bats also use the large bat box in the foreground (image copyright: Daniel Bridge)

When Essex Wildlife Trust built the Visitor Centre at Hanningfield Reservoir they couldn’t have imagined they were creating what was to become one of the largest soprano pipistrelle maternity roosts in East Anglia.  In fact it had been open several years before a young worker heard a strange squeaking noise in 2007.  Fortunately, the Education Officer identified the source of the noise as bats in the roof above the education room.  In the first year we carried out some monthly emergence counts before starting our regular fortnightly counts in 2008.

Whilst their chosen location provides a superb opportunity to watch the bats emerge it was not the easiest place to observe the activity in the roost and 2009 we were donated a large bat box which was mounted on a pole just outside the visitor centre.  The hope was that the bats would move across and we could put cameras in the box.  For several years a handful of bats would use the box but it was not until autumn 2015 that significant numbers were seen emerging and in 2016 the numbers continued to increase.  As well as watching the main roost and the box we have observed bats emerging from three other locations around the building.

From 2008 until 2014 the peak numbers fluctuated slightly from year to year but were between 450 and 500.  In 2015 the roost grew with almost every count beating the numbers from similar times in previous years with a yearly high of 676.  In 2016 it grew again and in early July it reached 1000 for the first time.

By 2018 the roost became the largest soprano pipistrelle roost in the country with a top count of almost 1800 bats!

The counts are a good opportunity for new bat enthusiasts to see them emerging from the roost.  It is also interesting viewing for the more experienced observers.  No equipment is needed but we do suggest you bring along a seat (a hat, coat and gloves is also useful as it can get chilly after sunset).   If you have a bat detector, bring it along but we usually have a couple available to listen to them both prior to emerging and then flying around.

Dates for this year have been cancelled due to the Covid-19 pandemic but please keep an eye on this page and the Essex Wildlife Trust website for updates.

You can keep up to date with the bats from home by visiting the bat cam webpage set up by the Essex Wildlife Trust and watch live footage of the bats in the especially made bat box here.

If you are interested in attending future counts, please contact Pete Claughton:  Pete will email details of meeting times a few days before each count.

More information about Hanningfield Reserve including directions can be found at –


If you would like to participate in Bat Conservation Trust’s National Bat Monitoring Programme please go to the following: NMBP home