"new caledonian crows consume a wide range of foods. these crows require tools to extract the larvae of wood boring beetles from their burrows. a bird pokes a larva with a stick until the larva is disturbed enough to bite the stick and hang on to it. the bird is then able to pull the larva out of its burrow. these larvae, with their unusual diet, have a distinct chemical that can be found in the feathers and blood of crows—allowing scientists to determine the percentage of the crows’ diet that is made up of beetle larvae. scientists found that the beetle larvae are so energy-rich that just a few could satisfy the daily energy requirement for a crow. the crows with the greatest skill in using a twig as a tool benefit most in terms of nutrition.
state one reason why the offspring of crows skilled at using twigs as tools would have the greatest chance of survival

state one reason why some members of a population of crows equally skilled in the use of twigs have different rates of survival."