Document Type

Presentation

Publication Date

4-26-2018

Advisor

Kristina Timmerman, Biology

Abstract

The Galápagos Lava Heron (Butorides striata sundevalli) is a small bird that is endemic to the Galápagos Islands, Ecuador. It is territorial and primarily preys on small fish. Currently, there is little research on these herons, so any information will be helpful in better understanding their ecological processes. During a biology course on the islands (July 2017), we observed the hunting patterns of herons specifically their strike patterns. We hypothesized that Lava Heron’s fishing practices would differ depending on water depth. We predicted the successful strike rates would be higher in shallower water, and herons would more likely to hunt standing in the water in shallow water versus standing on rocks when hunting in deeper water. To test our hypothesis, we observed Lava Herons as they hunted in a tidal stream for ten days in Puerto Baqueriza Moreno, Isla San Cristóbal. The water depth, whether they were successful, time between strikes, and location of where the heron was when it struck was recorded for each strike attempt. Our results showed a significant difference between the success in shallow versus deep water strikes (χ2= 63.74, df = 2, p < 0.001). Specifically, the strike success rate was higher in shallow water and more strikes into shallow water originated from water than land. These results suggest that shallow water is an important aspect in the Lava Heron’s territory. Hunting territories that lacked the important component of shallow water could result in negative impacts on the heron’s heath. Continued observation of strike patterns across an extended period of time would contribute more information to our results.

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