In late winter the garden seems to get louder every day. We're still months away from the exuberance of the full dawn chorus, but you get the sense that the birds are making plans, setting up territories and getting ready to start their frenzy of mating, and rearing young.
I've put up some new bird boxes and cleaned out old ones. But all of this work to attract birds to the garden would be pointless if I didn't have food for them in the summertime. And food for most garden birds means insects and other invertebrates, and lots of them!
You'll see it if you watch a pair of Blue Tits with a nest. The male and female birds will be coming back and forth constantly with mouthfuls of grubs, spiders, flies and anything else they can get their beaks around. Each chick can eat 100 food items per day, so a nest with 10 chicks inside needs 1000 food items per day. It takes chicks about three weeks to fledge, potentially consuming over 20,000 items between them in that time!
This is where moths come in. A lot of the food used to sustain bird nests will be in the form of juicy moth caterpillars. Some species of bird like Great Tits have even evolved to coincide their breeding with the time of year when caterpillars are usually most abundant. So it's fair to say that without moths, populations of many bird species would suffer. We can most easily see this around home gardens that might have lawns and flower borders, but no trees or shrubs to feed the moths that feed the birds.....they can be eerily quiet, with no breeding birds at all.
As a gardener, I see myself as tinkering about in a huge food web. My actions to introduce or control plants directly affects the insects in the garden, which in turn will affect the birds, and the birds and mammals that eat those birds. No garden can be everything to all animals, but if you want to boost your moth numbers, I'd recommend planting a hazel, willow, birch or crab apple (preferably all four!). Between them they are food for an enormous range of moth caterpillars, from the comical Puss Moth to the chunky Angle Shades. The great thing about these plants is that you can have them in any size of garden, and even in large pots. I've been growing a Hazel in a 50cm wide pot for 10 years and it looks fine, though a lot smaller than it would have been if it was growing in the ground.
One further thing to remember is to keep the ground underneath these trees and shrubs as wild as possible. Caterpillars will sometimes drop to the ground to pupate in the soil or leaf litter, so don't be too tidy! Nature has a way of looking after itself, and excessive tidiness harms plants as well as the insects around them.