If any animal ought to be able to expect a safely uneventful life, it’s the compact, guinea-pig-adjacent tuco-tuco. These South American rodents live in burrows underground, popping up into the dangerous above-ground just long enough to grab some veggies for dinner and then retreating again into their tunnels. Male tuco-tucos have the occasional reckless phase, during which they travel above-ground in search of tunnels inhabited not by familiar females but by attractively novel females; but aside from that, they stay underground.
Perhaps it’s fitting, then, that the danger also came from underground, pushing through its own tunnels, burrowing upwards like a hungry tuco-tuco. Late on June 2nd, 2011, and continuing through June 3rd, in the area around the Puyehue-Cordón Caulle volcanic complex in Chile, more than one thousand earthquakes shivered the earth. They came more and more frequently, until by midday June 4th they were coming more than twice per minute, a near-constant shuddering.
At 3:15pm a spot on the mountain exploded and sent a 5km-wide ash and gas plume into the sky.
If you live in a temperate climate and pay attention to your local birds, you have probably noticed that their preferences for companionship change with the seasons. In spring, pairs stick close by each other and three’s a crowd—any third-wheel interloper is likely to be chased off in a flurry of angry wingbeats. But in fall and winter, the birds suddenly become community minded, travelling around in flocks of dozens of their fellows. In Chicago in the winter you can find trees liberally decorated with the round orange forms of fluffed-up American Robins, bearing more than a passing resemblance to Christmas tree ornaments. Even in the Bay Area, not generally known for its seasonal variation, huge flocks of quietly chirruping Dark-eyed Juncos make it clear that (mild, occasionally rainy) winter has arrived.
Not pictured: about fifteen of this robin’s winter friends.
Why flock in winter? Or, why flock only in winter?
I’ve been meaning to write about this topic for a while—now xkcd has beaten me to it:
Oh, well. Since the comic doesn’t actually answer the question, I’m hoping you’re all still interested! (Also, at the end there will be a bonus discussion of ant rain. Yes, ant rain. You won’t find that on xkcd!)
The season of the summer disaster movie is upon us: Godzilla is stomping San Francisco, and I’m sure we’re all eagerly anticipating the premiere of Sharknado 2. To liven up the cinemas a bit, as a relief from the overabundance of sequels (I mean really, Sharknado 2!), I would like to propose a new genre mash-up: the animated talking birds disaster movie. It would be like those dancing penguin movies, or the solemn-looking owl movie (I have seen none of these…), plus disasters. The first one could be called Hailstorm!
It would not be a children’s movie. It would be terrifying.
It hailed on us a few days ago for about half an hour. The hail was mostly small, not larger than 1 cm in diameter, and the only animal reaction I saw was a decidedly alarmed chickaree—although to be fair, chickarees almost always look alarmed. I saw no evidence of damage afterwards; all of the junco nests we were monitoring weathered the storm just fine.
You know the hail isn’t too bad when you can safely hide from it in a tent.
But sometimes hail is a sharper-fanged beast.
Last year, I started the field season as soon as the university spring semester ended, because my field assistants were undergraduates and needed to take their finals before heading off into the mountains. That turned out to be too late, as we found that some of the juncos had started breeding without us. So this year I found some awesome non-undergraduate volunteers and went out earlier.
But I might have started a little too early.
My tent, our first morning in the field.
We’d known it was going to rain, and I thought it had – a particularly light-sounding rain pattering on my tent throughout the night. When I woke up I thought my tent had been covered in seeds washed loose by the rain. Then I stuck my head outside.
In fact it was better than rain: drier, and still permitting us to boil water for breakfast.
Our stoves boiling water for breakfast.
Female Wood Duck in Chicago in the winter.
A reader question today! Dolores asks: Would the body heat of a modest mixed gathering of water birds (gulls, ducks etc) melt ice at the edges of a pond?
The answer to this depends on context. We can start by establishing some extreme end-points: one duck at the edge of a huge lake in way-below-freezing weather would not be able to melt any ice.
Female Common Goldeneye in Lake Michigan: it’s a good thing the lake is already melted, ‘cos you’re not going to melt anything.
Twenty ducks splashing around spiritedly in a kiddie pool with the barest skin of ice in weather just at the freezing point would probably, if you waited long enough, cause the ice to melt.
Between our two endpoints are more “normal” circumstances: a group of waterbirds hanging out at a pond. Could they melt any ice?
Photo by Steve Ryan
You have (I hope!) seen news lately about the Rim Fire, which has been burning in Stanislaus National Forest next to Yosemite National Park. It began near the “Rim of the World” scenic viewpoint off Highway 120, and has been making Yosemite visitors and residents of Groveland quite nervous. It has burned over 200,000 acres and is reportedly 32% contained. A collection of pretty incredible photos of the fire is here.
First: no, this year’s juncos are not currently on fire. My field sites this year are in Stanislaus National Forest, but considerably further north. We have, however, seen smoke and had bits of white ash falling around us.
But of course, even if my juncos aren’t in the fire, other juncos are. And Chipping Sparrows, and American Robins, and mice, and gopher snakes… So what does wildlife do when the world starts burning around it? Are all the animals in that 200,000+ acres doomed?
Two weeks ago, it rained on us for a solid 22 hours. (Which, I discovered, is exactly the time it takes for puddles to start forming inside my tent.) So when it got grey and thundery at the beginning of last week, I jumped: “We’ve got to process this junco quickly! Take down the nets! We have to get back to camp to cover the firewood!”
Of course, it didn’t rain. The next time it got grey and thundery, I jumped less: “Let’s take down one net and keep this one. Tell me if you see lightning.” It didn’t rain.
The third time it got grey and thundery, I didn’t jump at all. Then it actually started raining—but I really wanted another junco. So we caught a male in (very light) rain and banded him under a tree, naming him KKRA, which sounds a bit like the thunder that was rolling in the distance.
KKRA, who has one white feather on his cheek
Happy New Year! In honor of brand-shiny-new 2013, I have… a continuation of the last post. I left a few things out of that post, since it was starting to get quite long; and then in the course of researching to answer some comments, I found some more things; so here are a few more ways that birds keep warm.
I’m currently visiting Chicago, relishing the finger-stiffening, face-numbing cold and wind that make up a proper midwest winter. Whenever I look out from the warmth of my big puffy coat and see a bird, I feel a little bad for enjoying the weather so much. I can go home and make myself hot tea; they can’t.
Very cold Tree Swallows (up in the Yukon, not Chicago!). Photo by Keith Williams
Like mammals, birds are endothermic (“warm-blooded”), meaning that they maintain their body temperature independent of the outside environment. This almost always means keeping themselves warmer than the outside air. Birds have quite high natural body temperatures, even higher than ours, so any given outside temperature seems even colder to them than it does to us.
Birds are also smaller than we are (well, omitting the ostrich), which means that they have a higher surface-area-to-volume ratio than we do. This is a problem because the volume (inside) of an animal is where heat is produced and stored, while the surface (skin) of the animal is where heat is lost to the environment. Imagine holding your hand in a bitter wind: how would you keep it warm? By making a fist. Making a fist reduces the surface-area-to-volume ratio of your hand, and lets it keep warm longer. In contrast, if you hold your hand out flat with all the fingers spread, your surface-area-to-volume ratio is larger, and your hand will get cold very quickly. Because birds have higher surface-area-to-volume ratios than we do, keeping warm is harder for them. How do they do it?