In addition to the Snowy Owl, the sly Winter Squid is also prone to disappearing come spring. For most players, the apparent hibernation of squid won't really amount to anything. However, if you're working on The Oceanographer achievement, you'll want to catch a squid before they disappear until next winter. The pesky squid can be fished off the coasts of Swamp of Sorrows, Blasted Lands, Tanaris, Badlands, the Cape of Stranglethorn, and also around Sunken Temple.
Both the fish and the pet have their own summery counterparts. However, while players may begin finding Summer Bass in fishing pools immediately after the Spring Equinox, the Qiraji Guardling for pet collectors will not be appearing until the onset of the Summer Solstice in June.