I always feel spring's arrived when I see the bees bringing in significant quantities of willow pollen. You can see the several incoming bees are quite yellow-looking, and have yellow parcels of pollen in the pollen baskets on their back legs. Nectar and honey are nothing but carbohydrate; bees get everything else from pollen, which is loaded with protein and fat. For the first time in five or six months, assuming the weather's warm enough for them to fly, they have a supply of fresh feed. They respond by feeding the queen better, causing her to lay more eggs. They have food available for the resulting larvae, and the colony soon expands, as bees begin to hatch out faster than the old ones die off.
This is the stream at the bottom of my plot, immediately after a heavy shower. Normally it's about half an inch deep at this point. After a thunderstorm, it becomes quite scary, and half the site may well be under water. I can't complain though; it's only the regular flooding which has stopped the site being built over long ago. Otherwise, it would be worth millions as building land.