Most birds are not at their best at the moment. The pressures of raising a family together with moulting means that it is better to photograph them when they are more photogenic.
Mammals, like the Bank Vole opposite, are multiple brooded so it matters less.
This one would come into the open to collect seed, the ultimate food for them. They go through periods of activity for perhaps 20 minutes, then take a rest before repeating. They are a challenge to photograph since (unlike Field Vole) they move fast with very quick reflexes.