Page 50 - BBC Wildlife Volume 36 #02

Taking a quick dip:
budgies may land on
water for a couple of
seconds to drink but
can’t hang around
because their plumage
isn’t waterproof.

synchronous hatching of budgie chicks 18 days later. As a temperature in the Australian outback can reach over 45°C
result, the similarly sized youngsters all consume food and (113°F). Grasses shrivel and die, and the only way budgies
grow at a broadly similar rate, meaning there are no runts can survive is by sticking together. Small groups will
and, in theory at least, they all have an equal shot at fledging. merge, which in turn will morph with other groups to form
It’s the female’s job to incubate the eggs while her progressively larger flocks, then search en masse for water
partner goes off to feed then when he returns, the pair flit and food. It’s in these conditions, perhaps after a bumper
off to a nearby branch where the male regurgitates food breeding season, that super-flocks form and the elusive
for the hungry mother. This might be the ultimate display emerald murmurations are seen.
of devotion… if you like regurgitated food. Fortified and One time, John witnessed a super-flock so big that it took
ready to feed her rapidly growing chicks, the female can 45 minutes to stream past. “It was mind-blowing,” he says.
then resume her maternal duties and, after six to eight “There is no other bird in Australia that flocks like this. They
weeks, the youngsters are ready to leave the nest. just kept coming.” Another time, he witnessed the bare
branches of the Simpson Desert’s coolabah trees turn green
BABY BOOM overnight when a super-flock of a million or more budgies
If resources are plentiful, the pair won’t wait long before came to settle on them. “It makes the hairs on the back of
nesting again, and wild budgies have been known to your neck stand up,” he says.
produce up to five broods in a single season. Numbers With such large numbers of birds on the wing at once,
can thus grow rapidly. John Young, senior ecologist for the it’s intriguing that they never seem to bump into one
Australian Wildlife Conservancy, who has more than 40 another mid-air. Biologist Mandyam Srinivasan from
years’ experience in the field, estimates that a population of Australia’s Queensland Brain Institute and colleagues
20,000 budgies can
swell to one of 2–3
million in as little as
12 months. “These CAPTIVE COLOURS
are birds of boom and
bust,” he tells me. “Last Wild budgies have two types of pigment
year, it started raining molecule: eumelanin, which is black;
in January and carried and psittacofulvin, which is yellow. When
on until October. The their feathers are doused in sunlight, the
budgie population eumelanin molecules reflect only the blue
just exploded.” part of the spectrum, which then passes
It makes sense through the yellow pigment layer to give
for wild budgies to the wild budgie its characteristic green
make hay when the colour. Through 150 years of selective
sun shines – or eggs breeding, budgie enthusiasts have made
when the rain falls – the most of 30-plus naturally occurring
because, in their world, mutations in colour-related genes, to
rainfall and therefore create a dazzling palette of budgies, in
food are inherently shades varying from yellow to grey to
unpredictable. Drought blue to purple. There are, however, no red Due to over a century
is a perennial hazard, budgies as the birds lack the pigment that of captive breeding,
and when it comes controls that colour. budgies can be a
variety of colours.
the land surface
50 BBC Wildlife