Friday, 23 December 2011

The Nativity Bird

Adoration of the Shepherds by Charles LeBrun 1689

All over the Christian world at this time of year you will see Nativity scenes - Jesus, Mary and Joseph in the stable. In the background there will be horses, and perhaps sheep brought by the shepherds, but one crucial animal is missing, one that undoubtedly was flitting around the stables of Bethlehem, the sparrow.

Sparrows (Passer domesticus) originated in the Middle East, and it would have practically impossible to keep them out of a stable. They would probably roost there, and later in the year there would be sparrow nests in the eaves. Where you have one sparrow you have several, being very gregarious little birds. Even in Biblical times they were so familiar as to be taken for granted - in the Gospel of Mathew, Jesus notes how (even) the flight of a sparrow is noted by God.

So common then, and common now, probably the most widely distributed bird in history. They tied their destiny to humans many many years ago, and it's worked. They flourish wherever man does, in his cities and on his farms. But why?

Firstly because they like cereal seeds, and man grows cereals, and make bread. But beyond that they are extremely adaptable. Whilst many birds are picky about nest sites, sparrows will nest almost anywhere, although they prefer holes in trees. The eaves of buildings are common, and almost any dense tree or shrub, but even street lights, apparently attracted to the warmth.

This brings us to the sparrow's 2nd advantage. They are immensely tolerant, "a bold and cheeky bird, but very wary and difficult to approach closely" according to my copy of the Ladybird Guide to British Birds (1956)*. Unlike many birds the noise and confusion of a modern city simply doesn't seem to bother them. Add an above average intelligence, a robust immune system, high fertility and amazing longevity (up to 23 years in captivity and even 19 years in the wild for one Danish bird) and you see why there are so many of them.

And, they're cute. They're tame and friendly and nice to watch. This is more of an evolutionary advantage than you might think. Sparrows were deliberately released into the Americas, in Brooklyn in 1852 and Buenos Aires in 1870, apparently as the teeming European immigrants missed having them around - they're now found from the Northern Territories of Canada to Tierra del Fuego. They are the commonest birds, with pigeons, in many Brazilian cities, from Porto Alegre in the south to Ipatinga in Minas Gerais, and they have even reached the edge of Amazonia.
Where there is man, there are sparrows.

So when you imagine the Nativity scene, shepherds, kings and a baby gurgling in the manger, add a few little brown birds flitting around in the background.

*Brian Vesey-Fitzgerald. The third book of British birds. Ladybird

Wednesday, 21 December 2011

EVERYTHING you ever wanted to know about the plants of the Amazon

A 353 page book has just been published, Fruit Trees and Useful Plants in Amazonian Life.

A co-production of the Food and Agriculture Organization (FAO), the Center for International Forestry Research (CIFOR) and People and Plants International (PPI) it aims to describe all the commercially or medically important plants in the Amazon region, and it is amazingly comprehensive.

For example
For the Buriti Palm (Mauritia flexuosa) there is a description of it's ecology, how they can be cultivated, the average yield (up to 360 kg per tree in a year!), economics (1 litre of Buriti juice costs about $1) and a COMPLETE guide to it's possible uses, including how to make traditional toys.
There is a description of the cultural significance of the plant, the animals that eat the fruit or nest in the branches, and even a recipe for Buriti frozen creme! All illustrated with line drawings.

And, the guide is free! It can be found at...

Friday, 16 December 2011

Nasty little spiders

The prime time news on Brazilian channel Globo recently showed a report on spiders*, specifically "Aranhas marroms", or "brown spiders" (translations never sound so impressive!). These little spiders might not look much, perhaps a bit larger than a normal spider, but they are a big problem.

"Brown spiders", (mostly Loxosceles similis) are found through out Brazil, from Para down through Minas and Sao Paulo to Rio Grande de Sul, with the southern state of Parana being something of a hotbed. However, unlike many spiders, the young don't make silk parachutes to travel on the wind and they've only got little legs, so they don't travel very far - colonies tend to be very dense, but localised. They're timid animals and will generally try to hide from humans, but 5,000 people are bitten each year, leading to fevers, skin lesions, and even death. So why is such a little spider so dangerous?

Well, it's all to do with their venom, which is incredibly toxic. Unlike some snake venoms, it's not neurotoxic as such, so victims don't go into paralysis or spasms, it is necrotic, which means that cells just die. Depending on how good a bite it got in, this can cause a little lesion the size of a bottle top, to one up to 40 cm wide. If this gets infected, or the toxin is carried in the blood stream to other organs (which is rare) the consequences can be very serious. The bizarre thing about their venom is that whilst some mammals such as rabbits and humans are very susceptible, mice and rats aren't, goodness knows why.

So what to do?


Virtually all cases of bites have been from spiders forced into close contact, by someone picking them up, or they were in clothing or shoes, so shake out any clothing. Don't, what ever you do, spray them with insecticide! It causes a nervous reaction making them very aggressive and much more likely to bite!


If you suspect you've been bitten, wash the site with soap and water, but don't try to squeeze or suck out the venom, you'll just spread it around. Go straight to a doctor, with, if possible, the spider - treatment is by anti-venom and it helps to know who bit you!

Every year, specialised (and very brave!) teams go out hunting around the southern city of Curitiba and catch thousands of spiders, which are "milked" for their poison. This is used to make the anti-venom. about 20,000 doses per year, to be distributed to hospitals all over Brazil.The actual technique used to make the anti-venom is explained nicely in the Globo piece.

Be nice to geckos

The principle predators of brown spiders are geckos, which presumably are immune to their toxin.

* The news report can be found here....