How to identify a bird you do not recognise

Colour is the first thing anybody notices and the least reliable thing available. It changes with light — a bird against a bright sky is a silhouette regardless of its plumage — and it changes with the bird, which may be a juvenile, in winter plumage, moulting, or simply a different sex from the one in the picture.

What does not change is shape, size, structure and behaviour. Those are what a birder is actually reading, usually in under a second, and they are learnable as a sequence rather than as an instinct.

Every step narrows the field. Most identifications are settled by step three.

1. 1

   Step 1: Size, against something known

   Not in centimetres — against a bird you already know. Smaller than a blackbird, bigger than a robin, sparrow-sized. Absolute size estimates in the field are notoriously unreliable; comparative ones are not.

   You will know it worked when: The candidate list drops by most of its length.

2. 2

   Step 2: Shape and structure

   Bill shape above all — thin and pointed for insects, stubby and conical for seeds, hooked for meat. Then leg length, tail length and body proportions. This is the single most informative feature and it does not vary with light.

   You will know it worked when: You have the family, which is most of the work.

3. 3

   Step 3: Behaviour

   What is it doing? Creeping up a trunk, hovering, wagging its tail, feeding on the ground, hanging upside down. Several species are identified in practice almost entirely by behaviour.

   You will know it worked when: Within a family, the genus or species.

4. 4

   Step 4: Habitat and season

   Where you are and what month it is excludes a great deal. Many confusions dissolve immediately once you check whether the bird is even in the country at that time of year.

   You will know it worked when: Improbable candidates are removed.

5. 5

   Step 5: Then plumage detail

   Wing bars, eye stripes, rump colour, the pattern of the face. Last, because it is the part most affected by light and age.

   You will know it worked when: The species, or a confident pair to choose between.

6. 6

   Step 6: Sound, if you have it

   Song and call settle a great many identifications that sight cannot, particularly in woodland. It is a separate skill worth building deliberately.

   You will know it worked when: Confirmation, or an identification you could not have made by eye.

This is the habit that separates people who improve from people who plateau. Opening a field guide while looking at the bird makes you match the bird to the nearest picture, and the nearest picture is very often wrong. Worse, once you have seen an illustration you will remember features you did not actually observe.

So write or sketch first — size, bill, behaviour, anything odd — and consult afterwards. The note does not have to be good. It has to be made before the book contaminates it.

What to record, in about fifteen seconds:

• Size comparison — Against a bird you know, not in numbers.
• Bill — Thin, conical, hooked, long, down-curved.
• What it was doing — And where — canopy, trunk, ground, water, air.
• Anything that stood out — A flash of rump colour in flight, a wing bar, a call.
• Date and place — Which does more identification work than beginners expect.