You can summon more creatures.
Benefit: Each time you cast a summoning spell that conjures more than one creature, add one to the total number of creatures summoned.
Pathfinder Roleplaying Game Ultimate Magic. © 2011, Paizo Publishing, LLC; Authors: Jason Bulmahn, Tim Hitchcock, Colin McComb, Rob McCreary, Jason Nelson, Stephen Radney-MacFarland, Sean K Reynolds, Owen K.C. Stephens, and Russ Taylor.