It’s when the food is available. That is when it’s not covered in snow and there is no frost covering the grass and, umm, vegetative parts of a plant’s herbs and the flowers the marmots like to eat.

这是食物可用的时候。那是当它没有被雪覆盖并且没有霜覆盖草地时，嗯，植物草药的营养部分和土拨鼠喜欢吃的花。