Every year about this time tiny spruce branch tips appear on the ground. What's going on? Red squirrels are clipping the tips to eat the buds, which are starting to swell as spring advances. Squirrels don't have much to eat right now. Their winter cone middens are getting low, and not much new growth has started. The spruce buds are probably both nutritious and tasty, at least until something better comes along.
I've watched squirrels clipping the tips. They're pretty quick, clipping the twig, turning it to bite off the bud, and dropping it almost in one motion. The first time I watched this activity I had a hard time picking up the bud removal part even with binoculars. To complicate things, sometimes the squirrel clips the twig and just drops it. I don't know if that's deliberate, but I suspect it is. Maybe the squirrels can discern whether or not the bud is a good one, or maybe the protective nest of needles on some buds is too much trouble.
I have another theory about the significance of this. Spruce cone crops are variable, with several years of low crops followed by a bumper crop. Red squirrels actually have bigger litters in the bumper year. This makes sense - the young squirrels will have better survival if there's lots of food for them in that difficult first winter. But what signal causes the squirrels to have bigger litters, which are born before the cones ripen in the late summer? Perhaps this twig clipping is a way to measure how many of those buds are normal vegetative buds, and how many are reproductive buds which will form male and female cones. Whatever the mechanism is, the squirrels somehow know when it's time to have lots of kids. Amazing.
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