Spring is just around the corner, but last week we saw the official harbinger of this change of the seasons. We saw a snow crane fly. That’s right, even though it was below freezing, we saw an insect. Just to remind you of how amazing this is, insects are cold-blooded, so when the temperature is below 0 degrees C, that’s usually the end of the line for any insect that’s out in the cold.
But snow crane flies are different. They produce glycerol (a sugar alcohol) in their blood, which makes them tolerant of below zero temperatures… But not too far below zero! If the temperature falls below about -7 or -8 degrees C, they risk “flash freezing.”
And this is why they are a harbinger of spring. For most of the winter, our temperatures sit well below -7 or -8 degrees C. It’s only when it starts to get warm that they can be out and about.
If you are out on snowshoes or skis at this time of year, watch for what looks like a spider walking across the snow. Snow crane flies have to walk everywhere, because they are wingless. This may seem unimpressive, but they’re pretty speedy: they can cover over a metre a minute (which is pretty good when you’re only 8 or 9 mm long).
Pretty soon our first migratory birds are going to show up, and our ground squirrels will pop out of hibernation, but until then, let the snow crane fly call out, “spring is here!”