Small wading bird (4)
This clue could be a double definition.
'small' is the first definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'wading bird' is the second definition.
(knot is a kind of wading bird)
Can you help me to learn more?
(Other definitions for knot that I've seen before include "Fastening; sea bird" , "Measure of speed on water" , "Tie; a cluster" , "measure of pace" , "Air mile" .)
(Another definition for dotterel that I've seen is " See bird".)