Norway Maple keys

[bushcraftbob]

A friend of mine has a Norway Maple outside her house, and it has a load of those helicopter type seeds on them. Are these edible? I remember seeing a post not so long ago about the sycamore keys being edible and quite pea like. As its a member of the same family will the Norway Maple keys be edible aswell? Is there a best time to pick and eat them? I.e do they fatten up as summer progresses? Do birds eat them?

Thanks