Obando
Fertility Rites

Fiesta
Jose W. Hernandez, 1990
In prehispanic times May was also the season for fertility dances. The Catholic Church pragmatically convinced the natives to conduct their dances in front of saint's images instead of idols.
sources:
Traveler's Companion: Philippines
http://www.asiatour.com/philippines/e-02trav/ep-tra12_e.htm
http://www.wowphilippines.com.ph/cgi-bin/dot/calendar/may.htm
http://festivals.pinoyshowcase.com/feasts-festivals.html