Wild Wild Life newsletter: The natural history of partridges and pears

By Penny Sarchet

Hello, and welcome to December’s Wild Wild Life, the monthly newsletter that celebrates the biodiversity of our planet’s animals plants and other organisms. To receive this free, monthly newsletter in your inbox, sign up here.

Of partridges (and pears)

Have you ever wondered, while singing The Twelve Days of Christmas, what a partridge in a pear tree looks like? This year, I decided to find out. We have two species of partridge in the UK – the native grey partridge (Perdix perdix) and the introduced red-legged partridge (Alectoris rufa). My favourite is the grey, but it’s much easier to see a red-legged these days.

As for which is the most likely to have been the subject of the song, we have a few clues. According to Birds Britannica (which would make a great present for a UK birder, incidentally), it has often been suggested that the partridge must have been a red-legged, as these are native to France and the song is thought to have French origins. But that seems something of a red herring, as grey partridges are native to France too and are more common there.

Another clue is which of the two is most likely to sit in a tree. Of course, the song itself is filled with silly and slightly fantastical imagery, but if we choose to take its lyrics seriously, then the partridge must be red-legged, as these do perch in trees. Grey partridges have been recorded in trees only a handful of times in the past century in the UK.

In fact, the sight of a grey partridge on the ground is becoming rarer too. UK populations declined by around 80 per cent in the 20th century and the species is on the country’s red list. Herbicides are currently the main suspect – the thinking is that the loss of farmland weeds has led to a crash in the insect populations needed to feed young partridges.

But shooting birds for sport is probably also having a significant impact on the UK’s bird crisis. Every year, the naturalised population of British red-legged partridges is augmented by millions of hand-reared birds, released for hunting. This far outnumbers the 75,000 pairs of grey partridges that live here. A recent analysis estimated that around 9 million red-legged partridges are injected into the UK’s ecosystems annually, plus more than 31 million ring-necked pheasants (Phasianus colchicus).

Together, the UK’s non-native game birds are thought to equal the biomass of all the UK’s native breeding birds during their peak season. Around a third of these game birds are shot, while the rest sustain high populations of foxes, rats and carrion crows, which is thought to have knock-on effects on vulnerable bird species like curlews and lapwings. We don’t know the full impacts of this extraordinary practice, but if you’d like to change that, I spotted this PhD position that hopes to find out.

I couldn’t end this segment without something on pears. This fruit, which is thought to have originated in Kazakhstan, became a phenomenon during the reign of France’s sun king Louis XIV, when hundreds of cultivars were grown. Ultimately, this led to what has been described by some as the greatest pear of all time: the Ansault pear. It reportedly tasted rich and sweet, with a delicate perfume, and was so creamy that you could spread it like butter. Unfortunately, Ansault trees were difficult to grow and the pears didn’t travel particularly well, so as fruit farming scaled up, the cultivar went extinct by the mid-twentieth century. I strongly recommend this episode of the podcast Gastropod for more on the Ansault pear and other foods I wish I could eat but never will.

Newly described species of the month

At long last, a millipede has been discovered that genuinely has more than a thousand legs. Eumillipes Persephone was discovered 60 metres underground in the Goldfields region of Western Australia and can have as many as 1306 legs – far more than previous record-holder’s 750. The animal is only 1 millimetre wide and has no eyes, but it does have large antennae and a beak for feeding. Its many legs may help it squeeze through narrow gaps, reports my colleague in Australia, Alice Klein.

This month I learned…

… that when horses stamp their hooves, they can make piles of sharp stone fragments that archaeologists may mistake for signs of ancient human tool-making. These stone-smashing equids now join capuchin monkeys in what my colleague Graham Lawton describes as the “unintentional toolmaker club”, which is a great band name if you happen to be looking for one.

Archive deep dive

Prompted by news that orcas are becoming more common in the Arctic Ocean, perhaps due to changes in sea ice, I’ve been enjoying looking back on the science of this species, my favourite of the cetaceans. I was extremely lucky to spend time with a pod off the coast of northern Japan in 2017, and while I was there, my guide told me about an annual phenomenon when hundreds of orcas gather together for reasons unknown to science. So I was excited to run this piece in 2019, looking at the possible reasons for such mysterious congregations, which also occur near Australia and Brazil.

Other remarkable findings include the discovery that, like us, the animal’s culture helps shape its evolution, and orca family groups benefit from the wisdom of their post-menopausal female elders. Drones have revealed the complex social lives of these animals, while orcas that appear to mimic human speech are yet more evidence that this intelligent species shouldn’t be kept captive.

Other wildlife news

I loved this video about how photographer Tim Flach takes his arresting bird portraits

Plants prioritise keeping their flowers cool in hot weather

A unique site in Spain is rich in both amber fossils and dinosaur bones

Risso’s dolphins have invented a new kind of dive

Your long read this month is a real treat – the question of whether animals have really moved to new continents on rafts or floating islands. I still struggle to imagine monkeys making a two-week crossing from Africa to the New World, but it’s hard to come up with an alternative explanation.

And with that, all that’s left is for me to wish you a safe and happy festive period and encourage you to get outside in nature if you can – it may be an effort, but you’ll always feel better for it. I’ll see you in 2022.