Casportpony's link to Safely administer oral meds (with photos) is an excellent option as well.@dawg53 told me a good way to administer liquid safeguard into their beaks. He said cradle the bird under your arm, so the feathers are secure, then (have your syringe ready with the dose) use the one hand to gently pull down the wattles which will open the beak, squirt in the dose and quickly let the beak close. They'll swallow and, since you did it quickly, it won't go down the wrong pipe. He said practice first w/o the medicine so you see how the beak opening works for you and get the rhythm down.
I learned the hard way about mixing the liquid goat wormer in water, it simply doesnt work.
It's always best to give wormers and antibiotics orally to birds. Wormers and medications mixed in water are a guessing game. You dont know if they drank enough of the treated water to be effective and sick birds drink very little or dont drink it at all. Birds drink less in cold weather as well.