Birds and street trees - blog post Stuart Checkley

As I started to write this blog at the end of March, I looked out of the window and saw in our silver birch a small brown bird. It was a chiffchaff, and it must have arrived overnight from North Africa where it had spent the winter. For twenty minutes it fed on a mixture of catkins and small insects which it caught on the wing, and then quite suddenly - it was off. Then at the beginning of April, as I was about to post the blog another African visitor arrived. This one was a blackcap and it was singing with a fluty voice from several of the trees in and around our garden. And by the end of April I expect to see a third African visitor - this time a willow warbler which will have come from South Africa. It is amazing that such tiny birds - smaller than a sparrow - make such long journeys, and it is gratifying to realise that our trees provide much needed refuelling for such heroic voyagers.

And in winter similar migrations take place from Scandinavia. Most winters a small flock of redwing (a thrush with red underwings) flies around Forest Hill in search of berries such as hawthorn and cotoneaster on which they gorge in our garden. And small finch-like birds from Scandinavia such as brambling, redpoll and siskin have also put in a short appearance on the same silver birch which is so loved by our African summer visitors.

The attraction of these trees is the myriad of small animals that live in and around them. Yesterday I saw a small bee, called a mining bee, drilling a pencil-sized hole in the ground under the silver birch, with the intention of filling it with nectar to feed larvae that will later emerge from eggs that will first have been laid at the bottom of the hole. And if you were to join us for lunch later under this same tree you would soon have met your first shield bug, which is present in huge numbers.

Trees are also important for the common garden birds that we all see. In their 2017 survey of garden birds the RSPB identified the ten most frequently seen garden birds. In order they were

House sparrow

Starling

Blackbird

Blue tit

Wood pigeon

Goldfinch

Robin

Great tit

Chaffinch

Long-tailed tit

Full details of the survey including images of the top ten birds can be found by searching online for “RSPB’s Big Garden Birdwatch: 2017 Results”

And again it is food that attracts them. Starlings don’t feed on trees but all of the other nine most common garden birds do. Blackbirds and robins hunt for small invertebrates in the leaf mould under trees, pigeons eat seeds which have fallen from trees and the others eat small animals on the tree. Most remarkable perhaps is the bluetit which while feeding a clutch of up to twelve fledglings must catch the equivalent of hundreds of caterpillars every day.

Some of the top ten garden birds (blue tits, great tits and starlings) nest in holes in trees or in nest boxes attached to them. Long-tailed tits construct a carefully camouflaged nest on the trunk of a tree, and others run the considerable risk of making an open nest in the branches of a tree. Only the largest of the garden birds such as magpies and crows succeed, and even then not always.

Finally, all of the top ten garden birds sing or call from our trees.

For obvious reasons, birds are unlikely to nest in street trees, but at quiet times of the day they can often be seen feeding on them or singing from them. And street trees share the same mini beasts (beetles, insects and other invertebrates) which make all of our trees so attractive to birds.

Further details of the wildlife that be found in and around our trees can be found in the excellent “RSPB Handbook of Garden Wildlife” by Peter Holden and Geoffrey Knight.