Dominance and Aggression Among Hummingbirds in the Cloud Forests of the Talamanca Mountains, Costa Rica

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Hummingbirds (Trochilidae) are known for being aggressive and territorial. By knowing hummingbirds are not very social, nor appear to enjoy having interactions with others, we wanted to observe how multiple species of Trochilidae interact with one another. The study was completed to observe if males of different Trochilidae would be more aggressive at hummingbird feeders over females. Three different feeder locations were decided on, spread across the Savegre Valley region near the Quetzal Education Research Center (QERC). Symbols were agreed upon in order to shorthand the exact series of events that were happening while we observed the feeders. Species and sex were noted with the behavior that was taking place. This study found that Talamanca Hummingbirds (E. spectabilis) were the most aggressive species out of the five observed. Three of the five species observed were endemic to the region and had a higher average of aggressive behavior than the non-endemic species. Each location had a different dominant species defending the hummingbird feeder in its territory. This study is important because it gives insight on how different Trochilidae interact with one another and can be used as different species of Trochilidae move into the Talamanca Mountain Range.