This is the 12772nd most frequent Russian word.
криком
"Криком" means "by a scream" or "with a scream" in English.
In this sentence, "криком" is used to describe the manner in which he called for help—by shouting.
Он позвал на помощь криком.
He called for help with a shout.
Here, "криком" implies the action or method of shouting in a figurative context, suggesting that raising one's voice isn't a solution.
Криком не решить эти проблемы.
Shouting won't solve these problems.
In this sentence, "криком" refers to the audible sound made that drew the bird's attention.