BBC Wildlife - UK 2020-07)

TheExplainer

A

nyonewho’swalkedalonga high

streetorstationplatformis likelyto

havebeenstartledbypigeonstakingoff

witha clatter.Theferalpigeonhaswingtip

(orouterprimary)feathersthatproduce

thispurposefulsoundonthedownstroke.

Pigeonsdon’tuseloudalarmcalls,like

blackbirdsorbluetits,somechanical

soundis theirwayofsurprisinga predator

orlettingtheirflockknowofdanger.

Woodpigeons incorporate wing-clapping

intotheirundulatingflightdisplayandwhen

takingofffroma nest,whileAustralia’s

crestedpigeonshavemodifiedflightfeathers

that‘whistle’whentheyliftoffsuddenly,

warningothersnearbytoscarper,too.A

varietyofotherbirdsalsomakemechanical

sounds,includingmalenightjarsandshort-

earedowls,whichclapwingsduringaerial

displays,andsnipe– whichdivethrough

theairtocreatea droningsoundastheir

tail feathers flutter like a flag.Ed Drewitt

Caninvertebrates

sneeze?

Whydopigeons y so noisily?

S

pongesprobablycan.Thesesimple,

ancientcreatureswerepossiblythe

firstmulticellularanimalstoevolve,at least

600 millionyearsago.It’sgenerallybeen

assumedthatoncetheswimminglarvae

settleontheseabed,spongesspendthe

restoftheiruneventfuladultlivessitting

still,endlesslyfilteringseawaterthrough

theporesintheirbodies.Butrecently,

scientistsstudied 30 years’worthof

time-lapsephotography,shot4,000m

deepoffthecoastofCalifornia,and

spottedspongesrhythmicallyexpanding

andcontracting.Onepossibleexplanation

is thattheyareexpellingirritatingparticles

fromtheirbodies,likea coughora sneeze.

It’sperhapsunsurprisingthatnobodynoticed

thesponges’slow-motionexpulsions,which

takeweeksormonthsbetweentheexpanding

‘ahh’ to the release of the ‘choo’.Helen Scales

BIOLOGY

ORNITHOLOGY

Ve t e ra n i se dt re esa reo l d

before their time.

Thisisa last-ditchconservation

techniquewheretreesare

prematurelyagedtocreatenew

habitatforrarespeciesthat

dependondecayingancient

trees.Maturetreesarecarefully

selected,theninoculatedwith

fungithatcauseheartrot,

speedinguptheprocess

bywhichthetreesdecayand

arehollowedout.Aspartofthe

BackfromtheBrinkproject,old

beechtreesinWindsorGreat

Parkhavebeenveteranisedto

helpanendangeredcranefly

foundhereandatjustone

othersiteworldwide.

Ben Hoare

Veteranisation

Barrel Sponge: Chris Newbert/Minden/FLPA; beech: Roger Creber/Alamy; pigeons: Terry Whittaker/2020VISION/NPL; frog: Dante Fenolio/Science Source/ardea.com

Gesundheit:marine

spongescomeinall

shapesandsizes,and

some seem to sneeze.

A pigeon’s

take-omight

get you in a flap.

84 BBC Wildlife July 2020

Q&A