Harrold Odell Country ParkBat Box Project Report

Introduction

Harrold Odell Country Park, in North Bedfordshire, has been surveyed by members of the Bedfordshire Bat Group for many years. The country park consists of approx 146 acres of lakes, river, mature trees and coppiced woodland, plus a large grazed meadow.

Surveys

Detector SurveysFor several years, up to 2016 three detector surveys a year, following a route around the lake took place. In 2016 2 detector surveys around the nature reserve were also undertaken, to expand out knowledge of how the bats were using the park. In 2017 7 bat detectors were placed around the park and left overnight to give a snapshot of the activity in the park (results pending).

Trapping surveysAs the detector surveys do not always pick up all species of bats, for example Brown Long Eared bats are often missed as they call quietly, and the Myotis species are very difficult to separate on the detector, a number of trapping surveys took place in 2014. These confirmed not only Daubenton’s bat, but also Natterer’s bat and brown long eared bat, bringing the number of species recorded at Harrold Odell Country Park to 8 (out of 12 recorded in Bedfordshire).

Roost HuntA tree roost survey was carried out in February 2014. This identified 28 trees which had bat roost potential, some have since fallen naturally.

Bat Species at Harrold Odell Country Park

Scientific name Species NotesMyotis daubentonii Daubenton’s Bat Forages over water bodies in the country park.Myotis nattereri Natterer’s Bat Caught in 2014, generally forages in trees.Pipistrellus pipistrellus Common Pipistrelle Found most often in the south / south-east areas of

the parkPipistrellus pygmaeus Soprano Pipistrelle Found throughout the park, including the bat boxes.Nyctalus noctula Noctule Largest British bat, found throughout the park.Eptesicus serotinus Serotine Found mainly near the river meadow, but has been

recorded throughout the park.Plecotus auritus Brown Long-Eared Bat Caught in 2014, forages in trees.Barbastella barbastellus Barbastelle Recorded once on a detector. A nationally rare bat,

associated with mature woodland.

The Bat Box Project

Bats use bat boxes in a different way to birds. They are used on a temporary basis, with bats moving roost frequently. Putting up boxes provides bats with an alternative roost site, even in areas with a lot of natural roosts.

In 2014 the Friends of Harrold Odell Country Park generously funded the purchase of 10 Schwegler woodcrete bat boxes (Schwegler Vogel- & Naturschutzprodukte GmbH Schorndorf, Germany). They were installed around the park in June 2014.

Three types of bat box were purchased:

Box Type Number Purchased2FN 42F 31FF 2 The boxes have been checked, under licence once a month form April to October, starting in August 2014. Bats found in the boxes were weighed, sexed, breeding condition noted and their forearms measured. Any bat droppings in the boxes were also recorded as they provide evidence of use by the bats.

Results Summary

The first survey, in August 2014, showed a very quick response to the bat boxes, with 2 of the boxes having droppings. By the end of the season 4 of the boxes had evidence of occupancy, with two boxes having bats in them.

In 2015, the spring surveys did not record either bats or droppings, but in late summer and autumn both bats and droppings were found, bringing the number of boxes used up to 5.

In 2016 many of the boxes had signs of bird nests or bird droppings, with 7 out of the 10 boxes containing birds nests. These were left undisturbed, and were removed after the young had fledged.The presence of the bird nests reduced the bat occupancy of the boxes in the spring, but in the autumn, bats were found in 3 of the boxes, with droppings found in 1 more box, bringing the total number of boxes used to 6 out of 10.

2017 started with 4 boxes occupied by bird nests, but one of the boxes was occupied by a bat. This bat was in a box that had not had a bat in in previous years, but had had bat droppings in.

All the bats found in the boxes that have been identified have been Soprano Pipistrelle (Pipistrellus pygmaeus).

Table 2 No. of bats found in each box

Box no. Total no. Bats

Total Soprano Pipistrelle

Total Unidentified Pipistrelle

1 0 02 0 03 4 44 0 05 1 16 0 07 7 78 9 7 29 1 110 3 3

Table 2 shows that boxes 7 and 8, both located in the south western section of the nature reserve have had the most bats found in them.

Table 3 Breakdown of bats found in Spring/ Summer and Autumn.Total No. bats No. Male bats No. Female bats

April-June 3 3 0July -October 15 7 8

So far, a larger no. of bats have been found in the autumn, compared to in the spring. Also female bats have not been found in the spring, but have been found in the boxes, with male bats in the autumn. As British bats mate in the autumn, and give birth in June/July, it is most likely that mixed roosts of males and females are mating bats.(c) Nicky Monsey 2017The lack of females found in the spring and summer, suggests that these bat boxes are not maternity roosts for soprano pipistrelles. The large no. of birds nests found in the spring/summer mean there is insufficient data for these seasons, and make drawing any firm conclusions impossible.