30 January 2021 | New Scientist | 55Tom Gauld
for New Scientist
Answers
The birds’ legs give them two
advantages: allowing them to take
off from or land on many surfaces,
and moving in a wide variety of
environments to find all kinds of
food and shelter for their nests.
Chris Feare
Haslemere, Surrey, UK
In a previous answer to this
question, Linda Phillips
contemplated why crows like to
stroll on roads (24 October 2020).
One answer was given in New
Scientist in the early 1970s.
Some researchers in the UK had
asked the same question about
rooks, highly sociable members of
the crow family. At that time, rooks
commonly fed on motorways
and the researchers hypothesised
that vibrations caused by traffic
simulated those of rainfall, which
encouraged worms to come to the
surface, providing an attractive
food source for rooks.
I had my doubts, because I had
never seen a worm with a tarmac-
piercing nose! So I began my own
research. On motorway journeys,
I counted all the rooks I saw and
recorded where they were feeding:
main road surface, hard shoulder
(or breakdown lane) or the verge.
Sadly, the data disappeared
with the demise of a computer.
However, the birds’ preference
was to feed at the boundary of the
hard shoulder and verge. Further
investigation revealed that insects
killed by passing vehicles
accumulated here and provided a
bounty of nutritious morsels that
didn’t require chasing or digging.
Incidentally, many of my
journeys were related to my
research on starlings. Motorway
service stations provided a
restaurant for these birds too,
with starlings parading around
car parks, scanning the front
number plates of parked vehicles
and picking off the dead insects
that adhered to them.Rooks are seen much less
frequently on motorways now,
possibly reflecting a decline
in UK insect populations.Recycling racket
Why is the noise so deafeningly loud
when I empty a bag of empty bottles
into the glass recycling hopper?Peter Peters,
Sherborne, Dorset, UK
Glass is hard, and rings for some
time when bottles clash because
it is a very stiff material. This effect
is cumulative in the short term,
so the sound intensifies. A good
example of this effect is when two
wine glasses, held by their stems
and very gently clashed, ring with
a surprisingly loud sound.
Additionally, recycling hoppers
made from sheet steel will vibrate
on impact, and their conical shape
focuses the noise of the clashing
glass on your ears.Pete Lloyd
Torremolinos, Spain
Could it be embarrassment? ❚Quick quiz #86
Answers1 Fermentation2 Facultative3 Four, all in Alaska: Denali, Mt St
Elias, Mt Foraker and Mt Bona4 Pineapple5 BhutanCryptic
Crossword #49
AnswersACROSS 1 Nori, 3 Albacore,
9 Bear hug, 10 Plain, 11 Lemon,
12 Alexia, 14 Single, 16 Cosset,
19 Amoeba, 21 Okapi,
24 Olive, 25 Nurture,
26 Migraine, 27 VentDOWN 1 Nebulise, 2 Realm,
4 Logjam, 5 Ample, 6 Ovaries,
7 Etna, 8 Phenol, 13 Strident,
15 Numbing, 17 Odours,
18 Tannin, 20 Enema,
22 Azure, 23 Zoom#97 Cabinet
reshuffle^
SolutionThe Ruritanian PM reshuffled the
five senior ministers as follows:Anerdine: Health to defence
Brinkman: Chancellor
to education
Crass: Defence to chancellor
Dyer: Home secretary to health
Eejit: Education to home secretaryWe were told Dyer goes to health,
so only Crass or Eejit could take
Dyer’s job (which isn’t chancellor).From this starting point, you will
find that the only cycle of moves
that works is ACBED, resulting in
the jobs listed above.“ In car parks, the birds
scanned the front
number plates of
parked vehicles to
pick off dead insects
that adhered to them”