Hi,
What size catheter do you use normally? french size.
When I use baby bird food, I use a size 18 since it seems to work on everything 400 grams or more, but when I use crumbles on larger birds, I use a 30. FWIW, I've noticed that the 35ml syringes last longer than the 60's.
Baby bird food is they way to go if you don't mind spending the money, crumbles are just too hard to get the right consistency with.
-Kathy