Rules of thumb for identifying birds

There's an old saying, ‘a crow in a crowd is a rook, a rook on its own is a crow'.

This succinctly describes how carrion crows are mostly encountered alone or in pairs, whereas rooks roost, nest and feed together in large, sociable congregations.

Although this isn’t infallible - numbers of crows might be seen together where there are good feeding opportunities, for example - it's nevertheless a good rule of thumb that can help when learning how to distinguish between these commonly confused birds.

Another old adage is used to tell the difference between treecreepers and nuthatches, phrased wonderfully by Molly Martin as 'if you see a bird creeping up a tree, it’s a Treecreeper, if it’s going down the hatch, it’s a Nuthatch!'

This is another rule of thumb: treecreepers only climb up or along trees, whereas nuthatches must be one of the only birds that can go headfirst down a tree.

Again, it’s not foolproof - nuthatches are equally adept at going up a tree - but it’s a general principle that helps with bird identification.

I'm interested in gathering any other sayings, rhymes or phrases that serve as rules of thumb for learning and remembering ways of identifying birds, so please share below any you’ve encountered or even created yourself.

Note: At the moment, I'm not collecting mnemonic devices for learning bird songs (although I’ve always found the phrase ‘little bit of bread with no cheese’ a delightful way of describing the call of a yellowhammer), but rather those that help identify birds from sight or from their behaviours.