Hummingbirds are amazing fliers. They fly forward at up to 26 miles per hour; they fly backward; they hover. They beat their wings 50 times a second, so all you see is a blur, with that enameled little body floating serenely in the middle. They are flight acrobats. They are flight artistes. How do they do that?
Rufous Hummingbird. Photo by M. LaBarbera
It helps that they are quite small. The amount of power that you can get out of your muscles increases as muscle mass (size) increases—bigger muscles, more power—but the amount of power increases less quickly than mass does. That is, if you double the size of the muscle, you get less than twice the amount of power out of it. This means that as an animal gets bigger, its ratio of muscle power to muscle mass decreases. An ant can carry enormous things for its size. A small bird can generate enough power with its muscles to hold its own body aloft and still in the air—to hover. A California Condor? Not so much. Hummingbirds’ small size means that they are, relative to their own body mass, very strong.
Small size is a Rufous Hummingbird’s secret weapon. Photo by M. LaBarbera
The chickarees have gone crazy. They spent the summer curious but shy, often fleeing us and then scolding from the safety of a tree. Now they seem to have no fear. They run under our table as we eat breakfast. They jump on top of our tents while we are inside. Sometimes they sneak in under the tent fly and look right at us, giant mammals separated from them only by some tent mesh, then saunter off unimpressed. As I was sitting with my back against a tree, one of them went up the other side of the trunk and then crept around to my side, at eye-level, until our faces were a bare few inches apart.
I have somewhat mixed feelings about this new friendliness. On the one hand, they’re cute.
Photo by M. LaBarbera
On the other hand, when we call them “plague squirrels,” it’s not just a term of endearment.
And then there’s the fact that they seem to be planning to steal my car.
It was well past dark when I first heard it: around 2 in the morning, it woke me in my tent. I lay awake for what felt like a long time, listening, trying—and failing—to classify the noise definitively as not a danger so I could go back to sleep. At the same time, I tried to think of what it sounded like, so that I could describe it the next morning. A large animal roar. A metal chair scraping across the floor. A death-metal chord. A train whistle.
Whatever it was, it neglected to devour me that night, and in the morning I was relieved to find that one of my field assistants had also been woken by the noise and shared my bewilderment. We agreed that it was primarily a cross between the bellow of some large mammal and the scrape of something mechanical, and so it was dubbed “the robot bear.”
The robot bear
The robot bear called most nights after that. Sometimes I thought it must be a noise of pain, or maybe rage—the tearing roughness in it sounded like strong emotion. Sometimes I was sure it was distant machinery; but we were surrounded by forest, and why would anyone be running machinery in the middle of the night?
We spend a lot of time looking for junco nests in my field work, which means we spend a lot of time looking at the ground, which means we see a lot of these little guys:
Pacific tree frogs come in two main flavors: brown and green.
Some frogs stay the same color for their entire lives, but some can change from brown to green, or vice versa, depending on whether the background is dark (brown) or light (green). You can see how this might be handy if you want to blend in with the background.
Despite pop culture’s image of the scientist as solitary genius, hidden away in his office surrounded by old coffee cups and rat mazes, with escaped fruit flies whirring around his head while theories fizz in his lonely brain, scientists can be quite social. Networking is important in science: it’s how you get jobs, find collaborators, and see new ways to think about your data. (Of course, the networking you’re doing is with other scientists, so escaped fruit flies may still be involved.) This week I’m attending the conference of the International Society for Behavioral Ecology in order to do just that, and the prospect of networking myself has made me think of other animals who network and the benefits they get from it.
There has been surprisingly little bycatch this year: we’re more than halfway through the field season and so far we’ve only had two non-juncos fly into our nets. As usual, we took some photos of them and then released them.
I love these guys: the red eye, the stripes on the throat, the thick grey bill.
Juncos nest on the ground (usually; sometimes they will nest higher, even reusing old robins’ nests, but I’ve never seen this myself. It’s probably because I’m short). This makes their nests tricky to find, since in the first place, there is a lot of “the ground” to search, and in the second place, you have to be really careful where you step while you search.
They don’t just nest on the ground, though: they often hide their nests underneath things. Some of them are quite good at it.
YABI’s nest. What do you mean, you can’t see it – it’s right there!