You can use keywords to narrow down your results. Keywords must be separated with space. The following keywords exist:

Ages:
1cy | 2cy | 3cy | Adult | Egg | Immature | Juvenile | Pullus | Subadult

Sexes:
Male | Female | Male & Female

Plumages:
Breeding | Eclipse | Winter

Postures:
Flock | Flying | Perched | Standing | Swimming

Behaviours:
Courtship | Displaying | Diving | Drinking | Eating | Fishing | Hunting | Mating | Nesting | Preening | Singing | Wing-stretch

Example of a search:
Adult Acorn Woodpecker Eating