One day in advance, make bluebirds. Tint 2 oz. fondant light blue. Use fondant roller with pink guide rings to roll out fondant 1/16 in. thick. Use chick cutter from Easter mini metal cutter set to cut out 12 to 14 bluebirds. Let dry 24 hours on cornstarch-covered cake board. Use black edible color marker to draw dot eyes for each bluebird.
Make cake circles. Prepare batter following recipe directions. Bake and cool completely. Use smallest round cutter from 101 cutter set to cut 48 cake circles. Use knife to cut each cake circle so it is level with treat pop, if necessary. Place cake circles in freezer until ready to assemble.
Assemble treat pops. Prepare buttercream icing following recipe directions. Tint portions rose, yellow and teal. Place cake circle in treat pop. Use tip 2A and rose icing to pipe a layer of icing. Repeat by piping a layer of teal icing and then yellow icing. Use tip 32 and rose icing to pipe a swirl on top. Position nest icing decoration on swirl and then fondant bird.