Tame to this kill fish and drag there body to it and once tamed if you feed them more dead fish corpses it will build up and lay a golden egg which is used as a buff to certain dinos or oil or a player buff
Use a horse to lasso it, then you can move it around to new fish spawns when the area gets cleared. The horse can also step on the duck to pin it down, or simply use the lasso to keep it close while tribemates gather fish.
Tamed Hesperornis WILL lay golden eggs, just takes a bit of time. I had mine on follow in the Redwoods river, and whistle attack targeted it on a fish. It must kill and harvest SEVERAL fish before going on land to lay an egg. It will either lay a normal duck egg, or it will lay the golden egg. It seems to be random, however mine laid about five normal eggs for every golden egg. If the type and size of fish matters, I have not figured that out yet. It will usually kill all types in one shot, and it will not agro every single sabertooth Salmon in the vicinity when it kills one so don't worry about them ganging up on your duck. I was using a lvl 80, probably tamed around level 50 or so and all I put points in was health. Have it kill every single fish in the river before you give up trying for that golden egg. It will happen, give it time. Hope this helps :)
Can't be picked up by anything while they are wild. They do aggro on you, and can walk through door frames, so you can kite them to a taming pen then use an itchy to bring those succulent salmon to you. Tamed a 140 last night in about 20 minutes.
These creatures are great for early players as they are a good source of oil (That I use to make grenades and destroy my enemy) and to get the oils you grab it's egg and throw it in a cooking pot and there you go, go make grenades and ruin your neibours stone base :D
If you insist on taming one without an Ichthythornis, a good thing to be aware of is that the Hesperonis will sometimes be unable to eat a fish it kills, swimming back and forth to try and "find" it.
You can pick up a fish it's killed and feed it to it, and it counts for tame progress.
Also be aware that if you drop a fish you've killed, it can eat your fish off the floor and it will not give tame progress.