19.2The first note is not necessarily the tonic

A melody in C major might begin on:

• E
• G
• A
• D

So do not assume:

first note = key.

Instead, ask where phrases settle.

Example:

“Happy Birthday” does not begin on scale degree 1.

Its pickup begins on:

5 → 5 → 6 → 5 → 1 → 7

in scale-degree terms.

That is much more useful than memorizing one absolute key.