BBC Wildlife - UK (2020-05)

Nest: Sam Hobson/NPL; octopus: Je

 Rotman/Getty; worm: Holger Casselmann/Creative Commons; elephant shrew: Herbert

Kratky/

mageBROKER

RF/Getty;

arva:

Ingo

Arndt/NPL;

mayfly:

W

dWonders

ofEurope/Rad

scs/NPL

D

uringunusuallyseverefloods,soils

becomeanaerobic(oxygen-free)

anddecaycreatestoxicchemicals.Up

to 75 percentoflargersoilinvertebrates

maydieorflyaway,butsurvivalvaries

accordingtospecies.Manyearthworms

andthelarvaeofbeetles,bugsandflies

movetothesurface,wherevastnumbers

geteatenbybirds.Ontheotherhand,

somespeciesofearthwormstayinthe

floodedsoil,copingduetotheirhigh

haemoglobincontent.Somebugsand

beetlessurviveasdormanteggsorcan

absorboxygenfromthewaterthrough

theirskin.A fewinvertebratesarealso

protectedinsidetheirwatertighthomes

• thequeenyellow-loosestrifebeemakes
  waterproofburrowsforherlarvae,lining
  thewallswithoil.AlexMorss

I

n February,a pairofmistle

thrushesinLeedsbecameonline

starsastheyrearedtheirchicksin

anunlikelylookingtraffic-lightnest.

Traditionally,thespecieschooses

a comfortablepositionatthebase

ofa branch,closetothetrunk.In

treelesslandscapes,however,mistle

thrusheswilluserockyledgesand

holesinwalls,sotrafficlightsprovide

a suitableequivalent,offeringthat

sameshelteredplatform.Theyalso

happilynestonwindow-ledges,

streetlightsanddrainpipes,aswell

asinfarmequipment.Blackbirdsdo

too,butasmistlethrushesarelarger,

palerandnoisier,theirbreeding

behaviouris moreobvioustopassers-

by.Thespecieshasalwaysnested

early,usuallyinMarch,thoughyou

mightexpectthistendencytobecome

strongerinurbansettings,which

arewarmerthanthesurrounding

countryside.Despitethis,mistle

thrushessadlyare‘Red’(themost

threatenedstatus)ontheUKRedList

ofspeciesofconservationconcern.

EdDrewitt

Dooodswipeout

animalsinthesoil?

Whydomistle

thrushesnest

intrac lights?

INVERTEBRATES

ORNITHOLOGY

MARINEBIOLOGY

A

n octopusleghashundreds

ofsuckersthatinstinctively

seizealmostanythingit comes

intocontactwith,yettheanimal’s

eightlimbsnevergrip

eachotherorget

tangledup.To

understand

howandwhy,

scientists

inIsrael

amputated

anoctopus

limb(giving

anassurance

thatit wouldgrow

backlater)andputit in

a tank,whereit remainedactive

formorethananhour.During

thattime,it grabbedatpretty

mucheverything,including

a skinnedoctopusarm,while

ignoringitsoriginalownerand

otheroctopuses,aswellas

amputatedlimbswiththeskin

stillon.Theresearchersthink

thata chemicalinoctopusskin

actsasa sucker-repellent,andthat

thissamechemicalstopsa live

animaltyingitselfinknots.They

hopetousethisdiscoverytobuild

betterbio-inspiredrobotsthatcan

shape-shiftlikeanoctopus.

HelenPilcher

Dooctopuslegsgettangled?

Octopuses avoid
tying themselves
in knots.

Hot property: additional

warmth generated by

the lights could be

behind this particular

choice of nesting spot.

Green worms are

able to live in

flooded soil.

86 BBC Wildlife May 2020