bee but no bumble

Since the earliest flowers opened at the end of winter there have been bees busily working the flowers in the garden.  Lots of small glossy black bumblebees and lighter coloured, hairier ones and I was stumped as neither  appeared on the bumblebee ID chart.

Watching the black bees feed at the flowers it was obvious what extraordinarily long tongues they had, perfect for the tubular flowers of the early comfrey, and the pollen baskets on their back legs stood out bright orange.  The lighter coloured ones were patrolling territories around patches of flowers, just like Wool Carder bees, but instead of pouncing on intruders aggressively as these do it was clear they were intent on mating with the black intruders - Wool Carders don't appear until June and I was confused.         With these characteristics noted an internet search followed.  

Turns out they are not two species of bumblebees at all but instead are Hairy Footed Flower Bees, Anthophora plumipes.  Aside from their lovely name I discovered they nest in holes in walls and other cavities, constructing cells from particles of soil, prefer deep-throated flowers and defend themselves with their large and hairy middle feet (love that!).  The lighter coloured males do patrol flowers on the look out for willing females but they don't chase off other species - though they will try it on with them.  I read they are easily recognised as not being bumblebees by their colour - there are no black bumblebees, by their flight pattern, quick and full of stops and starts - bumblebees fly slow and steadily, and by the shrillness of their 'buzz' (this last seems rather subjective, for me a buzz is a buzz).  

Here is a male, shrilly buzzing as he feeds on blue comfrey flowers.

They will all be gone soon until next year as they only fly from March to late May, wisely leaving the scene before aggressive Wool Carder males appear eager to club them to death with their spike-pronged tails.  Can't say I blame them.