Birding lends itself, no question, to amateur ornithology and to what in the old days was called nature-study and might now be referred to as basic field ecology. But that’s not the only way that it’s educational! Consider:

Geology, hydrology: If the uphill end of the field is muddy, the downhill end will be very, very muddy.
Physics: The mud will try to eat your shoes.
Phys. Ed.: But after a vigorous fight, you can thwart it.
History, Logic: If the barn burned down two years ago, you can’t use the hose in the barn to wash your shoes off now.
Sociology: Take your muddy shoes off before you go in the house, dammit.
Meteorology: Maybe it will rain again and wash your shoes off for you!