Volunteers and Visitors

Treefrog Breeding Frenzy!

Cesar Barrio-Amoros holds a PhD in biology and is a notable taxonomist, herpetologist, author, and photographer. Following his experience in the Osa, reflected below, Cesar has planned to lead a reptile and amphibian workshop at Piro Biological Station next May or June, the beginning of the wet season.

I have traveled throughout most of Latin America in search of amazing herping spectacles. In the Galapagos, I saw marine iguanas (Amblyrhynchus cristatus) and Galapagos giant tortoises (Chelonoidis nigra). I witnessed an astonishing diversity of poison frogs in Peru and made some interesting scientific discoveries on the Tepuis of Venezuela. My curiosity has now led me to one of the tiniest countries: Costa Rica. Here, the herpetological diversity is bewildering and vibrant. Due to Costa Rica’s intense biodiversity, it is not difficult for a photographer to capture nearly all of the herping species in a matter of years.


The gliding treefrog (Agalychnis spurrelli) was on the top of my herping list after learning about it on a BBC documentary. I have actually seen the individual species in the Caribbean and Pacific lowlands. However, I never saw one of those impressive reproductive aggregations where thousands of frogs gather in a pond and lay millions of eggs in just a few nights.

I was envious of the photographs my colleague, Manuel Sanchez, captured while working at Osa Conservation’s Piro Biological Station in the Osa Peninsula. I immediately scheduled a visit to see the event. When I arrived, Manuel informed me that the area was full of frogs, thousands were laying eggs in amplexus (amplectant pairs).

Around 6:00AM the next morning, we left for our journey along with herpetologist intern and researcher, Michelle Thompson. At the site, we noticed some bushes moving and, upon further investigation, realized there were a few frogs still laying eggs. The great wave was the previous night so only about 10% frogs remained.


Still, it was a breathtaking sight because they were completely surrounded by millions of eggs! Michelle and I were amazed — this was quite an experience for a herpetologist. Next time, I need to arrive a few days in advance in order to catch the whole spectacle!

Community Outreach, Environmental Education

2012 Osa Science Symposium

The 2012 Osa Science Symposium was attended by 14 presenters and many members of the environmental community

Osa Conservation recently hosted a science symposium at the Piro Research Center. The event brought together scientists and conservationists to share information and results from various research conducted throughout the Osa Peninsula.  The symposium was organized in partnership with representatives from ACOSA (Osa Conservation Area) and was attended by 14 presenters and many members of the environmental community.

The day began with welcoming remarks from Osa Conservation’s executive director, Manuel Ramírez and ACOSA research department head, Wendy Barrantes.  The gathering provided a space to discuss the current status of Osa’s diverse ecosystems and wildlife, as well as identify priority areas for further research. Participants identified the need for comprehensive studies of land use change in Osa, methodologies for estimating costs of environmental damage, calculations for carbon sequestration potential in primary and secondary forests, scientific techniques for recovering degraded forests and the development of a model to build incentives for reforestation in the peninsula.

The symposium strengthened communication and collaboration among scientists and environmentalists and also fomented the role of Osa Conservation as one of the main facilitators of research in the area. The event was a great success and we would like to thank the following presenters and all symposium attendees.  Thanks for making this year’s symposium a success!

Wendy Barrantes, ACOSA
Conserving the Osa, Overview and Future Directions

Karen Leavelle, Osa Conservation
Spatial Biology and Conservation of the Yellow-billed Cotinga

Guido Saboío, Osa Conservation
Sea Turtle Conservation Project, Piro-Carate Beaches

Reinaldo Aguilar, Los Charcos de Osa
Vascular Plants of the Osa

Pablo Riba, Proyecto Carey, Universidad de Costa Rica
Population Structure of Two Dioceus Hardwood Species in the Osa Peninsula

Edgar Malayassi, Instituto Tecnológico de Cartago
Carbon sequestration in secondary and primary forest, Osa Peninsula

Jesús Mora Molina, Guillermo Calvo Brenes, Instituto Tecnológico de Cartago
Evaluation and Classification of the Quality of Several Water Bodies in the Osa Peninsula

Aida Bustamante, Yaguará
Research and Conservation of big cats and their preys on the Osa Peninsula

Gloriana Chaverri, Boston University
The Use of Social Calls in the Search for Bat Refuges

Julieta Carranza , Walter Marín, Universidad de Costa Rica
Inventory and distribution of macro-fungi at La Leona, Corcovado National Park

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