When Jean sent me her photo of Waxwings this week, she also sent me this (left) showing a gorgeous hoarfrost on the berry-laden trees where her Waxwings were feeding.
Here too in Sussex we had one day during the week with a hoarfrost to remember. In the sunshine, the delicate crystals remained solely on the northern side of any twig or dried flower stalk like sprays of blossom (right).
And it all reminded me of a hoarfrost I photographed in my youth (below right - those were the days!), which built up over several days into the most incredible tracery of ice.
The relevance for gardening for wildlife is that, while it may all look entrancing, it also spells real trouble for some of our garden birds. This - and 'glaze', where freezing fog coats twigs and branches in ice - make it very difficult for birds to pick insects from off the bark.
Insects? In this weather? Well, yes - but not adult ones. If in winter you watch insect-eating birds such as the tits, Treecreepers and Wrens, they are still gleaning items from twigs and branches as they rove about.
Much of this will be insect larvae tucked in and under gaps in the bark. In the case of Long-tailed Tits, insect eggs are high on the menu.
Just imagine how difficult this is if everything is locked away by nature's frozen cling film. No wonder in really bad winters populations of the most vulnerable species can crash by 80%.
What to do about it in the garden? Keep up the supplementary feeding for those species that will use it. And for those that won't, such as Wrens and Treecreepers, if you've built up a good diverse habitat of shrubs and trees and log piles and creepers, it gives them the best chance they've got.