EASY 
1 dog (A), 1 hot-air balloon (B)

MEDIUM
1 chicken (C), 1 bird nest (D), 1 groundhog (E), 3 squirrels (F), 1 iron (G), birds (H)

HARD
3 ladybugs (I), 8 flies (J), 1 spider (K), 1 butterfly (L), 1 caterpillar (M), ants (N), mushrooms (O), 1 grasshopper (P), 1 mouse (Q), 1 frog (R), 1 elf (S)