HS2 – What to Expect: From bats to barn owls, train line’s impact on wildlife

A Bechstein's Bat found in woods in north Bucks. ''Credit: Toby Thorne of the North Bucks Bat Group
A Bechstein's Bat found in woods in north Bucks. ''Credit: Toby Thorne of the North Bucks Bat Group

Read HS2 Ltd’s report on the ecological impact of their rail line and you’d be forgiven for thinking there’s nothing to worry about.

The government agency simply has an answer for everything – including how it will protect the incredibly rare Bechstein’s Bat, the most high-profile animal to be affected by the line.

It admits the internationally-protected bats could be affected by habitat loss, but then adds that planting new woodland will compensate this.

But according to Matt Jackson, head of conservation strategy at the Berks, Bucks and Oxon Wildlife Trust, HS2 Ltd has over-egged the effectiveness of its mitigation measures.

“They seem pretty optimistic. What they are proposing does not go near what a normal planning application would propose for mitigation let alone an exemplar example for how to do things.”

The Bechstein’s bats located in woodland in north Bucks are in danger from loss of surrounding habitat for foraging and breeding.

Mr Jackson said: “In our patch they are not behaving normally as they fly across open land and will be crossing the HS2 line and we are very worried about impact.

“HS2 Ltd has proposed all sorts of mitigation to try to reduce the impact on the bats. Our big concern is it is just untried and untested and we are dealing with a very vulnerable population.”

Mr Jackson’s view is shared by the Bat Conservation Trust, which says HS2 Ltd is wrong to suggest that a complex habitat such as ancient woodland can be 
simply recreated.

They have slammed HS2 Ltd’s environmental statement outlining how it will minimise the impact.

Dr Carol Williams, director of conservation, said: “We are concerned at the inadequate standard of surveying that supports this Environmental Statement. Also of concern is the interpretation of the survey findings into flawed proposals to negate impacts. This is particularly evident when considering the losses of ancient woodland. On such a major project, with equally major potential ramifications for bats and other wildlife it is vital that high professional standards are maintained. We are shocked by this Environmental Statement.”

Then there is the law of unintended consequences.

Mr Jackson is worried that putting in new habitats may upset the balance of Mother Nature, creating an ‘ecological tension’.

The answer for him is to extend the replanting areas away from the line, lessening their impact and also making sure animals are well away from the track.

“They have got a line on a map and they’re just looking either side of that. But then extending it will cost them more money.”

The one animal that HS2 Ltd does begrudgingly admit will suffer is the humble barn owl, beloved of children on school trips into the countryside.

As well as the removal of nests to make way for the line, the slow, low-flying birds are likely to be hit by the train, wiping them out within a 1.5km of the track.

Mr Jackson said: “It’s something like a 2% decline in the barn owl population we are expecting to disappear as a result of HS2.

“HS2 Ltd can’t provide nesting sites along the line (because they would be killed by the train) so they are a bit stuffed really. Barn owls will also lose foraging sites where they would normally hunt for small mammals.”



There are at least 30 grass snakes living around the golf course and also a small population of adders.

They are likely to be wiped out during construction, but HS2 Ltd says snakes should reappear on ecological compensation areas created south of sewage works and south of Oat Close.


There are at least three colonies containing more than 200 individuals in woods between Woodham and Claydon.

This species is very rare in the UK and are also near the threatened level at European level.

HS2 Ltd claims there will be ‘no significant effect’ on their conservation status. None of the known roosts will be removed to make way for HS2 but the loss of surrounding habitat could affect their viability.

However, HS2 Ltd says they will create more than 20ha of woodland planting which ‘will compensate for the loss of habitat required for breeding and foraging’. It does admit that the proposed planting will not be sufficiently mature to provide habitat linkages immediately. ‘As such framentation of habitats used by Bechstein’s bats and other species will still arise in the years following construction. In order to reduce the time for establishment, replacement habitats will be created where reasonably practicable prior to construction of the proposed scheme’.


There are around 40 colonies located in woods between Woodham and Claydon and at Calvert Jubilee Nature Reserve.

This species of butterfly is endangered in the UK. HS2 Ltd says they will be affected by the line’s construction due to habitat loss, representing ‘an adverse effect on the conservation status at a the district level’.

They say the loss of colonies will be mitigated by plating blackthorn on ‘green’ HS2 bridges and habitat

creation areas.

This will ‘greatly increase available habitat once blackthorn is sufficiently mature to provide habitat for egg-laying (estimated at 10-15 years). Following maturation of habitat there will be no adverse effects on the conservation status of black hairstreak in the area’.


Dozens of barn owl territories are recorded within 1.5km of the proposed line (11 nests alone in the Aylesbury area, amounting to 5.5% of the

county population). HS2 Ltd admits they may be affected during construction. Three nests will be removed in the Aylesbury area and at least 70ha of foraging habitat lost.

The operation of the train line will have a severe impact, as barn owls are often killed by trains because they hunt low over habitats near embankments and are slow moving. HS2 admits: ‘Evidence suggests such mortality is likely to result in the loss of all breeding populations of barn owls within 1.5km of the proposed scheme’.

It says that to offset these losses, ‘opportunities to provide barn owl nesting boxes in areas greater than 1.5km from the route will be explored with local landowners’. This will ‘be likely to increase numbers of barn owls’ and ‘offset the adverse effect’.