| Summary: | 碩士 === 國立東華大學 === 自然資源與環境學系 === 100 === Nest-guarding is an important strategy for successful reproduction. Birds may adopt different nest defense behavior according to the degree of threat from the intruders. The yellow-bellied prinia (Prinia flaviventris) and plain prinia (P. inornata) are two sympatric, phylogenetically closely related species. They are similar in size and share the same feeding ecology, but differ in some breeding traits. They suffer predation risk from the same avian predator, and may have different pressures from brood parasites. In this study, we tested their responses to the intruders during different breeding stages. We presented mounted specimens of an avian predator (long-tailed shrike, Lanius schach), brood parasite (oriental cuckoo, Cuculus optatus) and a control (pale thrush, Turdus pallidus) near the nest and recorded the nest owners’ responses. Both species showed significant avoidance to the predator regardless of breeding stages. They did not attack and performed very few mobbing behaviors toward the shrike model. However, they differed in other behaviors: the yellow-bellied prinias were more alarmed by the shrike, with more approachings and hidings, while the plain prinia tended to be away from the shrike and used alarm calls to distract the predator. For the responses to the brood parasites, the yellow-bellied prinia displayed significant attacking behavior toward the cuckoo model at the egg stage, but not in the nestling stage. The plain prinias showed no significant anti-cuckoo behavior at either breeding stage. The strong aggression toward the cuckoo and high similarity in their egg coloration indicates that the yellow-bellied prinia may be the main host for the oriental cuckoo. Our results highlighted the different nest guarding strategies of the two species: When facing the same predator, they used different nest defense behaviors; the responses to the brood parasites also differed, possibly reflecting their susceptibility to being brood-parasitized.
|
|---|
