# Bat bridge

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{{Short description|Road construction to aid the navigation of bats}}
{{Update|date=February 2023}}
[[File:Batbridge.jpg|thumb|Bat bridge on the [A38](/source/A38_road) [Dobwalls](/source/Dobwalls) Bypass, Cornwall, UK. (2009)]]
A '''bat bridge''' is a structure of varying construction crossing a new or altered road to aid the navigation of [bat](/source/bat)s following the destruction of a [hedge](/source/hedge)row, and to cause the bats to cross the roadway at a sufficient height to avoid traffic. Bats are thought to follow the lines of hedgerows and woods, and removing these may confuse the bats.

The theory is that these "bridges" will be seen by the bats' sonar as linear features sufficiently similar to the old hedgerows as to provide an adequate substitute.<ref>{{cite web|title=New bypass going 'batty' to help the environment |publisher=Western Morning News, The Plymouth (UK) |date=April 5, 2008| access-date = 2009-09-12| url = http://www.encyclopedia.com/doc/1P2-15978017.html}}</ref>  The English [Highways Agency](/source/Highways_Agency) is performing a study of those on the Dobwalls bypass to determine if this assumption is justified.{{When?|date=February 2023}}{{Citation needed|date=February 2023}}

==Usage==

===France ===
[[File:Chiroptéroduc sur l'A89 en France.jpg|thumbnail|right|Bat bridge on the [A89](/source/A89_autoroute), near [Balbigny](/source/Balbigny), Loire, France]]
The first bridge to be installed in France is on the [A65](/source/A65_autoroute) motorway between junctions for [Roquefort](/source/Roquefort%2C_Landes) and [Caloy](/source/Caloy) in the [Landes](/source/Landes_(department)) department.<ref>[http://www.sudouest.fr/2012/02/28/un-couloir-a-chauves-souris-644852-706.php Un couloir à chauves-souris, Sud-Ouest, février 2012]</ref>

Two additional bat bridges were completed in November 2012 near [Balbigny](/source/Balbigny), on the [A89](/source/A89_autoroute) motorway.<ref>[http://rhone-alpes.france3.fr/2012/11/21/balbigny-une-passerelle-pour-chauve-souris-au-dessus-de-l-a89-148988.html Reportage de France 3]</ref><ref>[http://www.denisriou.com/autoroute-a89-chiropteroduc Photographies de l'installation des ouvrages]</ref>

=== Germany ===

Two metal bridges were built in 2013 to protect the [Mouse-eared Bat](/source/Mouse-eared_Bat) at [Biberach an der Riss](/source/Biberach_an_der_Riss), [Baden-Wuerttemberg](/source/Baden-Wuerttemberg). The structures cost £375,000 (400,000 €).<ref>{{cite news |date=2013-11-02 |title=Warum fliegen die nicht einfach drüber? |publisher=[Kölner Stadt-Anzeiger](/source/K%C3%B6lner_Stadt-Anzeiger) |url=http://www.ksta.de/panorama/umstrittene-fledermausbruecke-warum-fliegen-die-nicht-einfach-drueber-,15189504,24882430.html |access-date=2 April 2015 |archive-url=https://web.archive.org/web/20131106092905/http://www.ksta.de/panorama/umstrittene-fledermausbruecke-warum-fliegen-die-nicht-einfach-drueber-%2C15189504%2C24882430%2Cview%2CprintVersion.html |archive-date=2013-11-06 |quote=Rund 400 000 Euro wurden dafür ausgegeben |archive-format=Print version |trans-quote=Around 400,000 euros were spent on it}}</ref>

===United Kingdom===
{{More citations needed|section|date=February 2023}}
Bat bridges have been implemented in the [United Kingdom](/source/United_Kingdom) by various agencies, including the Highways Agency, with support of the [Bat Conservation Trust](/source/Bat_Conservation_Trust).<ref name=":0">{{cite news |date=2014-08-04 |title=A11 Elveden bypass to be shut for bat bridges |work=BBC News |url=https://www.bbc.co.uk/news/uk-england-28642459 |access-date=2015-04-02}}</ref>

At A38 Dobwalls Bypass, the bridges are more elaborate and sophisticated than the earlier Welsh structures, which consisted of cables strung from poles.<ref name=":1">{{cite web |title=New Bat bridge for bypass: Marishal Thompson Group - Tree Subsidence, Arboriculture, Ecology and Landscape Architecture throughout the UK |url=http://marishalthompson.co.uk/news/new-bat-bridge-for-bypass/ |archive-url=https://web.archive.org/web/20091107135016/http://marishalthompson.co.uk/news/new-bat-bridge-for-bypass/ |archive-date=2009-11-07 |access-date=2009-09-12 |publisher=Marishalthompson.co.uk}}</ref><ref name="Hansard">{{cite web |title=House of Lords Written Answers 10 November 2009: Bats |url=https://publications.parliament.uk/pa/ld200809/ldhansrd/text/91110w0001.htm |access-date=5 June 2011 |publisher=United Kingdom Parliament}}</ref> 
{| class="wikitable"
|+Bat bridges in the United Kingdom
|-
! Name !! Road !! Opened !! Approx. length!! Single or dual carriageway !! Placement !! Approx. cost !! Other details
!Ref.
|-
| Stainburn and Great Clifton Bypass || [A66](/source/A66_road) || December 2002 || Gantry || Single (three-lane carriageway) || || ||
|
|-
| High and Low Newton || [A590](/source/A590) || April 2008 || 33 m || Dual || In cutting || £45,000
|
|
|-
| [Dobwalls](/source/Dobwalls) <br /> (2 Structures) || [A38](/source/A38_road) || June 2008 || Structure 1: 59.47 m, Structure 2: 70 m || Dual || At Grade/In Cutting || £300,000 || One structure consists of three steel towers with cables suspended between them carrying mesh panels. The other consists of a single span of cables and mesh panels between concrete and steel anchors either side of a cutting. In the Dobwalls scheme, a third bat-crossing consisted of a raised parapet modification to a new road bridge, Havett Road.
|<ref name=":1" /><ref name="Hansard" />
|-
| Parton to Lillyhall || [A595](/source/A595) || Dec 2008 || 34 m || Dual || On embankment || £34,133
|
|
|-
| Haydon Bridge || [A69](/source/A69_road) || April 2009 || 19.5 || Single || In cutting || £60,000
|
|-
| [Pwllheli](/source/Pwllheli) and [Criccieth](/source/Criccieth) || [A497](/source/A497) || 2006 || || Single || At Grade || || A bat bridge was installed following the upgrade of the A497 to help the six species of bats in the area to cross the road.
|<ref>{{cite news |date=2006-05-02 |title=UK &#124; Wales &#124; North West Wales &#124; 'Green' road helps bats to cross |work=BBC News |url=https://news.bbc.co.uk/2/hi/uk_news/wales/north_west/4964618.stm |access-date=2009-09-12}}</ref>
|-
| [Elveden](/source/Elveden) || [A11](/source/A11_road_(England))|| 2014 || || Dual || Various || £350,000 || Six bat bridges.
|<ref name=":0" /><ref>{{cite news |date=22 October 2015 |title=Bats reject 'safe way' bridges over Norfolk - Suffolk dual carriageway |work=BBC News |url=https://www.bbc.co.uk/news/uk-england-34605886 |access-date=27 January 2020}}</ref>
|-
| Gilwern to [Abergavenny](/source/Abergavenny) || [A465](/source/A465) || 2007 || || Dual || Embankment || || Two bat bridges were constructed during road upgrade in locations where full bridges previously stood.
|<ref>{{cite news |last=Roberts |first=Geneviève |date=2007-03-31 |title=How did the bats cross the road? By using the special 'bat bridge' - Nature, Environment |newspaper=The Independent |location=London |url=https://www.independent.co.uk/environment/nature/how-did-the-bats-cross-the-road-by-using-the-special-bat-bridge-442561.html |access-date=2009-09-12}}{{dead link|date=August 2021|bot=medic}}{{cbignore|bot=medic}}</ref>
|-
| [Groeslon](/source/Groeslon) || [A487](/source/A487) || 2010 || || Single || || || The road runs through the [Glynllifon](/source/Glynllifon) Special Area of Conservation which is home to a [lesser horseshoe bat](/source/lesser_horseshoe_bat) colony.
|<ref>{{cite news |date=30 January 2010 |title=Road closure for new aerial bat crossing |work=BBC News |url=https://news.bbc.co.uk/2/hi/uk_news/wales/north_west/8487932.stm |access-date=5 June 2011}}</ref>
|-
| [Norwich](/source/Norwich) || [A1270](/source/A1270) || 2017 || || Dual || || £1,000,000 || Seven bat bridges on the [Norwich Northern Distributor Road](/source/Norwich_Northern_Distributor_Road).
|<ref>{{cite news |date=26 Jan 2020 |title=Norwich NDR bat bridges 'are not working' |work=BBC News |url=https://www.bbc.co.uk/news/uk-england-norfolk-51193389 |access-date=26 Jan 2020}}</ref><ref>{{cite news |date=21 Apr 2015 |title=Detailed section plan of the NDR |publisher=Norfolk County Council |url=https://www.norfolk.gov.uk/-/media/norfolk/downloads/roads-and-transport/ndr/route-maps/detailed-section-plan-of-the-ndr.pdf |access-date=11 Dec 2017}}</ref>
|}

== Criticism ==
The overall cost of bat bridges was criticised by [Lord Marlesford](/source/Lord_Marlesford) in the [House of Lords](/source/House_of_Lords) in 2011, for being funded "at a time when we're having to cut a lot of public spending".<ref>{{cite news|url=https://www.telegraph.co.uk/news/politics/8827505/Bridges-too-far-The-500000-bat-crossings.html|title=Bridges too far? The £500,000 bat crossings}}</ref>

A team from the University of Leeds examined the effectiveness of bat bridges, gantries and underpasses. They found that one underpass, placed on a commuting route, was used by 96% of bats, but few bats used the other underpasses and gantries, preferring routes which put them in the path of traffic.<ref>{{cite journal|last1=Berthinussen|first1=Anna|last2=Altringham|first2=John|last3=Fenton|first3=Brock|title=Do Bat Gantries and Underpasses Help Bats Cross Roads Safely?|journal=PLOS ONE|date=13 June 2012|volume=7|issue=6|article-number=e38775|doi=10.1371/journal.pone.0038775|pmid=22719941|pmc=3374807|doi-access=free}}</ref><ref>{{cite web|title=Bat bridges don't work|url=http://www.leeds.ac.uk/news/article/3253/bat_bridges_dont_work|publisher=University of Leeds|access-date=15 June 2014|date=14 June 2012}}</ref>

==See also==
*[Amphibian and reptile tunnel](/source/Amphibian_and_reptile_tunnel)
*[Squirrel bridge](/source/Squirrel_bridge)
*[Wildlife crossing](/source/Wildlife_crossing)

==References==
{{reflist}}

==External links==
*[http://www.bats.org.uk/pages/roads.html Roads, Bat Bridges and Gantries: A position statement from Bat Conservation Trust]

Category:Bats and humans
Category:Bat conservation
Category:Conservation projects
Category:Bridges
Category:Wildlife crossings

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Adapted from the Wikipedia article [Bat bridge](https://en.wikipedia.org/wiki/Bat_bridge) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Bat_bridge?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.
