From the OED, we have dovetail initially defined as “something in the shape of a dove’s tail”.
Around the mid-1500s, dovetail is applied not just to things shaped like a dove’s tail, but a specific form of joinery in which a mortise and tenon are cut in complementary shapes and fitted together. This can be applied to larger, architectural features or to smaller, cabinetmaking techniques. Here’s an example of dovetail joints on a house.
Here is a similar construction for a drawer.
Why dove’s tails? Why not fingers and gloves or teeth? Let’s look.
Hmm… Not really seeing it.
Still not seeing it.
Wait, wait, the OED specifies in its definition of dovetail joint that it is the “expanded tail” that inspired the term.
Perhaps this one is better.
This simply goes to show that a) language is largely a creative effort and b) it’s not just semanticists that really like birds.