At the edge of one of the forest fragment that we are studying as part of Panama PLUMAS.

The Panama PLUMAS (Precipitation and Land-Use in Multiple Avian Species) Project studies bird communities inhabiting 24 forest plot across the Isthmus of Panama to assess the concurrent, interactive effects of habitat configuration (e.g. degree of fragmentation, fragment size) and precipitation. Sites exhibit maximum variation in rainfall and fragment size while allowing good ecological replication; sites include two replicate forest tracts from each unique combination of three size categories (6-40ha, 70-120ha, >500ha) and three rainfall bands (1800-2100mm, 2200-2600mm, 3000-3300mm), with six additional small forest tracts. Fragment sizes were selected because [1] meta-analyses show that ~100ha fragment may be sufficient—and <50ha insufficient—to maintain ecosystem functioning, and [2] >500ha is larger than the maximum dispersal distance for many understory birds. Co-founded and co-developed with Dr. Corey Tarwater, we are examining these impacts on community structuring, population demography, morphology (beaks, nests, etc.) and behavior (foraging competition, antipredatory behavior). We have several projects that we are exploring across the Isthmus of Panama:

Bite-force variation across precipitation and fragmentation gradients

(Top) BCL Principal Investigator Dr. Patrick Kelley measures the bite-force of a white-whiskered puffbird (Malacoptila panamensis) in March 2020. (Bottom) Close-up of the 3D-printed bite-force device; it is fitted to a Fluke 28 II True-RMS Rugged IP 67 Industrial Digital Multimeter.

Work currently being prepared for submission suggests variation in bill morphology across the precipitation gradient, a pattern that is likely linked to availability of certain types of insect prey. Naturally, we next wanted to explore if beaks exhibit concurrent variation in bite performance, which may aid individuals as they capture and process prey items.

In 2020, just prior to having to leave Panama due to the COVID pandemic, we initiated a bite-force project to build a preliminary dataset to be used in grant applications. The Behavioral Complexity Lab used 3D printing–in conjunction with a simple resistance meter–to design a bite-force transducer capable of measuring the bite-force of different bird species in the field. This highly portable system was very successful, and we are now in the process of redesigning the device to enable rapid field calibration prior to measurement. The Behavioral Complexity Lab now has an operational Prusa Mini 3D printer in the lab for rapid prototyping.

Map of Barro Colorado Island (Panama), the locations where black-crowned antshrikes were sampled, and its ecological variation (forest age and slope)

Variation in acoustic communication across environmental gradients

Dr. Kelley has over 20 years’ experience with bioacoustic analysis (stingless bees, three species of monkey, many bird species). Current work in the Behavioral Complexity Lab focuses on understanding bioacoustic signals of tropical birds. We are currently preparing work for publication on adult ontogeny of call structure in suboscine birds. And, we have conducted several experiments examining the salience of syllable rate in birds in Panama and in the Galapagos. Using a large-scale song survey on Barro Colorado Island, Panama, the Behavioral Complexity Lab has found that–in additional to other effects–distance to island
edge best predicted song structure in a suboscine bird; this is being prepared for publication. We have conducted additional playback experiments to test various hypotheses (e.g. the numerical odds hypothesis) about how territories are effectively defended. This is a research area that we are now actively focusing on, given (1) how important acoustic communication is in dense habitats like tropical forests, and (2) that many experiments can be done in a short period of time.


[10-Dec-2022] We have just gotten word that the Panama PLUMAS Project has received full funding ($763,000) from the United States National Science Foundation! Please consider joining our field team (as a PhD student or field technician)!