Lots of Bright Yellow Pollen Coming In

It was bright and sunny today. In the warmth the bees were out in force. many delivered loads of bright yellow pollen to the hives. The red maple is blooming now and the pollen probably is coming from that. According to this page, which is organized by blooming time of the species, the pollen of the red maple is grey, but the pollen of the maple tree is generally yellow. So the bees are probably delivering pollen from a maple tree - not specifically the red maple.