What percentage of each day must a Goldcrest feed for survival in deep winter?

Answer

90% of each day

Observations suggest that in the depths of winter when food is scarce, a Goldcrest must feed for at least 90% of each day just to survive due to the energy cost of its continuous rapid flight.

What percentage of each day must a Goldcrest feed for survival in deep winter?
birdspeedflightgoldcrest