h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I am always fascinated by bird migration. I have a private theory, backed up by the usual mysticism and no science, that large bird migrations are important for the health of the biosphere in some way. And that the planetary system should be regarded as a superorganism.

Can you imagine how flourishing Earth was in the days when flights of birds darkened the skies on a regular basis? Now, if some idiot sees a dozen grackles in his backyard, he gets 'creeped out'and starts mentioning Hitchcock. (World's silliest movie...)

Anyway, I love these little guys! Heck, I love all birds except those shrikes that impale other birds on sharp sticks, which is just Wrong.

But you've really brought out the beauty in this one!

We get both willow warblers and chiffchaffs here in the summer, though I couldn't tell the difference!

I've seen blackcaps (sylvia atricapilla) in our garden in the winter - they can overwinter in our part of Britain.

I agree that the planet is a superorganism. Bird migration might have other functions on the planetary scale but I can think of two: first, they tie together places over vast distances, which brings a kind of unity to the global biosphere (and of course they're not alone in doing this), and for us humans, they show the importance of freedom of movement.

Minorvogonpoet, the differences between willow warblers and chiffchaffs are discussed in this video. Easiest is by their songs and calls:

https://www.youtube.com/watch?v=wixRxZ94dMc

Interesting about the overwintering blackcaps! We actually get some here in South Africa from time to time, but it's considered a rare vagrant.

Thanks Willem.

The RSPB says that blackcaps from Germany and Northern Europe are increasingly over-wintering in the UK. Apparently chiffchaffs can over-winter here too.