Codes that work in both the hunt view and the map view:

DGGOLDENEGG - makes birds more curious, less likely to spook
DGLUCKYDUCK - many, many birds :)

Only the map view:

DGBIRDSEYE - show bird icons
DGWARP - allows hunter to teleport across map
DGDAFFY - Ducks only
DGMOTHER - Geese only

Only the hunt view:

DGEGGSACT - stops gun wobble
DGFAMINE - makes birds look for a feeding site
DGPREDATOR - predator effect (like Trophy Hunter)
DGSNOWGOOSE - weather effects
DGTOUGHDAY - Birds look for a rest spot
DGYADAYADA - Increase hunter talk