Comments by Date (9)
WoW Insider has an article on when the festival occurs. There are actually TWO per Sunday; one at 9pm (runs to 9:23), another at 11pm (to 11:23). http://wow.joystiq.com/2013/04/04/the-overachiever-time-zones-battle-pets-and-an-achievement-yo/
4:10am server time, a bunch pop up (5-6). I get a Common, Yell to the zone that they're up, but only 2 others in zone, no reply. I wait a bit out of politeness, then battle a couple more, 3rd one's Rare!
19, 45 is a great place to farm these and other Krasarang critters. A bunch of them run around among spider nests. I got rare Sifang Otter Pup & Savory Beetle as secondaries. Also, if you have an AOE attack, you can "farm" the non-battle critters for Critter Kill Squad guild achievement. (Appearently, killing a lot of them also summons an elite mob named Feverbite in the center of the area.)
I bought one today (12/12/12). I can confirm that this is now an account-wide pet; I can see and use it on other characters than the one it was "bound" to. I can also right-click it and "Put In Cage", though we'll see if I still can after 24 hours.
There's a level-2 bat in the Undercity courtyard, in the middle of the Pilgrim stuff. Maybe associated with it?
One thing I haven't seen mentioned is that though they are level 17, you only haved to fight one of them in a battle. There's no 2nd or 3rd pet in the fight, I guess because it's the only pet in the zone so no alternates appear.
Got my Rare as a secondary off a Strand Crab by the nagas north of Booty Bay, like previous poster.
I found a cat on Sunstrider Island, the BE starting area. There are a bunch of just-critter cats running around The Sunspire building, and one turns battleable now and then.
Also, camping the Crazy Cat Lady's house in Elwynn can work; there's usually only a single cat marked for battle, but it respawns after a couple of minutes. I finally got my Rare that way. Cats often show up as secondary in Arathi, but are mostly Poor.
It shows up as a secondary combatant in Thousand Needles, but it was not capturable for me. I think you still have to buy it.