When your trying to get milk it is Easier with a team, but for those without that option try this. (Without risking bird) Build the trap as normal within spyglass range of trench. Make sure u have hole in back of cage (preferably the size of and argie). Then make a 1 ceiling sized tower just on corner of dragon entry side cage. Ramp it down the side of cage(NO LADDER). Place a keypad in a tiny adobe but behind cage just out of reach of dragon attack with the behemoths pincode in mind(must power keypad). Now that that's done 1 person with no speed body cand use a long neck rifle to Argo dragon into cage and close it in with 0 risk to a bird. I've done it with no movement speed increase. (Everything must be stone or metal on cage)
I got a level 150 lightning egg and I was so excited to hatch the egg...that when I went to put the egg down I accidentally ate it instead. :( ps4 users: R2 ISN'T GONNA DROP THE EGG YOU'RE GONNA EAT IT LIKE ANY OTHER EGG. REMEMBER THIS. LOGIC BEFORE EXCITMENT.