Listening to the First Philippine Republic’s Station at a Tropical Cave, Aguinaldo

Recording water post typhoon by one day, at Aguinaldo Cave , Biak Na Bato National Park, Bulacan, Luzon with BNBNP cave team caver Rexel.

It’s November 11th, one day after typhoon storm rains that had headed its way to northern Luzon had thankfully been dispersed and broken when it hit first land the Sierra Madres mountains. Still the rains fell, and the rivers at Biak Na Bato National Park were overflowing and more than full. Recording with hydrophones outside of Cave Aguinaldo I was able to capture sounds of shooting water in tides that I had not ever heard before in freshwater , sea or ocean water. It was like shooting stars moving through the water out to the river stream.

This was the cave named after the first president of the first Philippine Republic, Emilio Aguinaldo. With the Philippine Republic he fought against the Spanish and the Americans to help bring the Philippines to its first independent republic in 1899, a significant moment ending eras of colonialism in the Philippines. The republic hid , worked and moved through these caves, and this cave was where Emilio Aguinaldo stationed his troops.

The sound of the water was amazing. It was high also and we were not able to walk into this cave, where actually there is a path to connect to several of the larger caves that we had passed such as Bahay Paniki ( bat cave ) which is large and cathedral like with rivers moving swiftly at the bottom.

The vining ficus trees, Tibig and Balete, in the Philippines are known as trees of water and their ability to hold water source. Some of them grow long vines which can get so large they become their own trunks. The vining ficus dangle here outside of Aguinaldo’s cave.

I listen here to the water pools, the crevices, undercurrents, cave streams rushing out to the rivers large current and mix into the overflow quickly and madly making its way downwards.

It’s an abundance of rhythms, shapes, sounds, existing next to each other simultaneously. The hydrophone recordings were amazing.

It was such a contrast next to the recordings inside the other caves we visited with stalactite drips and quiet mixed surfaces. I’m grateful I was able to capture this entrance and intersection to contemplate the reality of the first Philippine Republic and its president here , 126 years ago.

-Susie Ibarra

Sound Health Habitat Journal

November 21, 2025