While walking along the beach yesterday evening, a huge number of small black beetles swarmed around my wife, landing on her hair and clothing. Thankfully she's an adult, and not prone to running around screaming, giving me a chance to have a look. Turns out they are Pollen Beetles, which fly in from nearby oilseed rape crops to gather in open flowers where they feed on ripe pollen. Or they land on anything pretty and yellow, or blonde in my wife's case.
Today the beetles are on all the yellow flowers in my garden.