I know there are some people, like myself, who are interested in trying to catch the Legendary Birds roaming around Runko, and I believe I have found a solid strategy for catching them.
First, go to the Soul Cult and catch yourself a Gothita, it's hidden ability Shadow Tag is the only thing that can effectively stop the Birds from escaping, and give you endless chances with the pokeballs. Sure, there are some trapping moves, but those depend on the speed of your pokemon, and are somewhat risky. First, get a fast pokemon with Mean Look. Either hidden abilities don't work in PokeUE, or Shadow Tag is useless against a legendary.
Second, level it up to about thirty, and buy a lot of Repels. You'll need these to keep away the pathetic, lower leveled, not Legendary pokemon that you would otherwise encounter nonstop trying this. Now, since your
Gothita pokemon is around level thirty, when you use the Repels in lower level Routes, the only pokemon you can possibly encounter would be the Legendary Birds, and your Gothita pokemon has a decent chance of survival while you throw endless pokeballs at that Legendary.
Third, pick two Routes somewhere within the set area for that Bird (I do recall that once upon a time, when this game was on Gamejolt, Savordez said he planned to set each of the Birds to be in a certain area of Runko, such as Northern Runko, Eastern Runko, and Western Runko. Unfortunately, I don't know which ones are in what area...) that you can easily run back and forth between, and have patches of grass not far from each other. Of course, a town with a Route nearby would also work, so long as there was grass near enough to the town.
Now, if my strategy here has any flaws that I overlooked, or you have something better, please make a post here explaining such.