Elephants in my eyes!

Hey Li!

So... reading and thinking so much about elephants has affected the way I'm seeing things!

Today, I was walking through Central Park to meet Nika, my former student and friend who's a badass adult and filmmaker now (here's us meeting!):)

On my walk, I started watching these robins. They were running and then standing incredible still, and then pecking the ground and sometimes successfully grabbing earthworms with their beaks! Below is a video that I took on my phone of the robins:

robins-hunting from Molly Josephs on Vimeo.

Since I read so much and watched videos of elephants freezing and picking up low-frequency sounds through their feet (see video below), I thought to myself: "Woah, these robins are picking up vibrations in the soil through their feet and that's how they find the earthworms! They freeze in order to feel the soil and locate the worms, and that's how they find the worms! This all makes sense because they obviously can't see them because their underground!"

(from Utopia Scientific)

There's been a few experiments on this and the jury is still out. One experiment that robins do, like most birds, especially those that hunt during the day, use their good eyesight to find prey. And this could be the case especially since perhaps they're wI read atching the soil move when they freeze and that's how they're finding the worms.

But then I read this study which tried to block out each of robins' senses one-by-one to see which one they use to hunt prey. The researchers used mealworms and some earthworms. Theuy made trays filled with baked soil that contained no other small invertebrates. They drew a grid on the tray and did all kinds of experiments.

In the first one, they buried dead vs. live mealworms. The robins struck the ground with their beak more near the live mealworms than dead ones. This suggests that they don't use smell to find the worms becuase technically they should be able to smell both dead and live mealworms equally well and should have struck near both of them equally as frequently if they were using smell.

When the researchers elimiated vibrotactile cues by hanging the tray on the wall of the aviary instead of putting in the ground, the robins were still able to find the worms relatively well. But the experiment was alittle weird — the researchers used fewer worms and did fewer trials in this experiment.

When the researcjers buried the worms below a sheet of cardboard beneath soil so that the robins couldn't see the worms, the robins still struck at them closely to where they were, which suggests they're not actually using their eyes.

When the researchers buried a speaker in the soil that was playing whitenoise, the robins didn't strike at the soil as accurately (i.e. close to worms) as during other experiments. From this, the researchers concluded that the robins are using auditory clues to find the worms.

To me, it seems that playing white noise underground could also have interfered with vibrotactile clues.

The researchers also recorded the sound from the mealworms moving around to see how loud it was. It was incredibly low volume. This, plus the fact that robins have small heads with small ears that aren't that far apart makes me dubious. Their ears are not like those of owls who's ears are relatively large and far apart. One is higher up than the other and their distance and asymmetry increases the time between which each ear receives the sound waves form an event. This this allows owls to locate where sound waves are coming form more precisely and this is how they hunt in the dark.

Anyway, my bet would be that robins are using their eyes, their ears, and their feet and... who else knows, maybe their noses too! I also just kind of hope that their using their feet like elephants, because how cool would that be to look at robins in the spring in urban parks and to then think of elephants!

XOXOXOXOX

And here's another one!