January 2020 - Thrushes, Re-wilding

We saw a couple of thrushes on the field at the back recently.  They were quite a distance away so it was difficult to see what sort of thrushes they were even with binoculars.  There are four possibilities for thrush-like birds in this country – song thrush, mistle thrush, redwing and fieldfare.  (The thrush family – Turdidae - is a large family that includes robins, redstarts, wheatears and our more familiar blackbird.)  The redwing and fieldfare are more numerous in the winter as they are joined by immigrants from Scandinavia, but these are distinctive birds – the fieldfare is well marked and has a grey back, and the redwing has a distinctive eye stripe.  The thrushes on the field were not so distinctive which meant they were either mistle thrushes or song thrushes.  The mistle thrush has slightly bolder speckles on its breast and a more upright stance.  I could see both of those characteristics so I guessed at mistle thrush.  This was confirmed when they flew off and I saw a flash of white under their wings.  The four thrushes each have a patch under the wing near the shoulder – which could be called an armpit if there no ornithologists about – that is diagnostic.   The fieldfare and mistle thrush both have a white patch, the song thrush has a buff-coloured patch and the redwing is aptly named.

Song Thrush

Fieldfare  (This one found in its summer residence - Sweden)

Wildlife can be difficult to see as it is, quite rightly, wary of humans.  I saw a book recently that addresses that problem.  It is by Simon Barnes and is called Rewild Yourself.  The theme of the book is things you can do in your garden to attract wildlife.  Rewilding is becoming a popular concept if not a popular way of managing land.  The idea is that larger mammals or predators are introduced to an area which then changes the ecology and allows nature to recover from human intervention.  It is a ‘stepping back’ from nature and is the polar opposite to conservation which seeks to preserve what may already be a degraded habitat.  The Knepp estate in West Sussex and Yellowstone Park in the USA are famous examples of rewilding.  Yellowstone has been hugely successful.  Wolves were reintroduced and the water quality improved!  How so?  Basically, the wolves killed the deer that were overgrazing riverside habitat which meant that the deer couldn’t graze where they could be easy targets.  This allowed trees and bushes to grow, which in turn attracted beavers that built dams which slowed the rivers and allowed fish to thrive and a balance was restored that improved the water quality.  It has had other benefits as well.  Trees and bushes have stabilized the riverbanks and reduced soil erosion, and remarkably, pronghorn deer that were becoming rare are now thriving as there is more grazing available due to the reduction in red deer numbers. (Red deer are called elk in the USA by the way.)  The trees and bushes meant more insects, more birds, and more small mammals and more birds of prey.  This process whereby the introduction of a species at the top of the food chain has a dramatic effect on many other species is called a trophic cascade.

The Knepp estate in West Sussex has had similar success.  No top predators there but free roaming cattle, pigs, deer and ponies have created a mosaic of different habitats that have resulted in thriving populations of purple emperor butterflies, turtle doves and nightingales in little more than a decade.  It’s on our list for a visit in the near future.  Meanwhile we’ll just have to carry on working on our own small patch where just allowing the grass to grow allows a lot more species to get a foothold.  I guess wolves and bears aren’t an option here?

Sadly, I find that I don't have any good pictures of mistle thrush or redwing.  Something I hope  to remedy in the near future.