Phillip Wills tells an amusing story of an encounter with a bird in one of his books.
Flying in the US nationals in Texas on one task he was down to 800ft over inhospitable terrain, going round and round in plus or minus 100ft/min just holding height and no more.
He knew that he was on the edge of a thermal and in one direction lay the core , but which way was it ? If he took the wrong direction he would be faced with an ignominious and expensive out landing.
Suddenly his salvation appeared. A soaring hawk on rigid wings came into view from the south. Clearly he had been in the same thermal and on seeing this monster had assumed the pilot's wisdom was in proportion to his size so he had come over to see if he had better lift.
"He did a couple of circles just over my head and I could almost see his beak curl into a contemptuous sneer as he tasted the miserable rags of my lift, then he turned and glided straight back the way he had come. No thought of saving the face of my theoretically superior species prevailed upon me to hesitate, I straightened up and followed my feathered friend and in two minutes was circling up at 500 ft/min to cloud base."