Patch Size Effects on Avian Foraging Behaviour: Implications for Tropical Forest Restoration Design

background

This study looks at bird behavior in restoration sites in southern Costa Rica. While multiple studies examine the presence of birds in restored forest, few studies examine behavior in these sites.

Research Goals & Methods

The restoration sites were 4-5 years old, planted with Terminalia amazonica, Vochysia guatemalensis, Erythrina poeppigiana, and Inga edulis. Initial planting was conducted in restoration patches of 50m x 50m, planted either entirely or in small mini-patches, but patches were reclassified at the time of study into smaller (100s of square meters) and larger (1000s of square meters). Four species of insectivorous and omnivorous bird species were monitored: Cherrie’s tanager (Ramphocelus costaricensis), rufouscapped warbler (Basileuterus rufifrons), common tody-flycatcher (Todirostrum cinereum) and plain wren (Thryothorus modestus)

Conclusions & Takeaways

Researchers found greater foraging success (higher prey attack rate and lower search effort) in larger patches for three of the four bird species monitored. Arthropod abundance was higher in the larger patches (measured by gram of arthropod biomass / gram of clipped vegetation). Researchers also examined bird vigilance (in response to perceived predation), but results were less conclusive. Authors conclude that limited resources in small patches could have long term effects on the fitness of birds, and that restoration activities should focus on larger patches when possible.