Jennyfer Rodriguez Femat
Master's thesis research on female territoriality at the nest, nest variation, and conspicuous nests as possible signals of territorial 'claims' in the Streak-backed Oriole (Icterus pustulatus)
(Spanish version)
I am working on my masters project with Dr. Marcela Osorio from UAEM (Morelos University) and Dr. Troy Murphy from Queen's University.
I am interested in understanding territoriality in tropical birds, and am specifically focusing on how females defend their nest sites from intruding orioles. I am conducting behavioral observations to determine the role each sex plays in defending the nest site, and also how songs and other vocalizations function in communicating with indruders and within a pair.
I am also interested in understanding if there is a reason behind the great amount of variation we observe in nest size and shape (see pics to right). I want to know why orioles build such extraordinary pendulum nests, and if females build their nests in ways that communicate something about territoriality or something about the female herself. In other words, I want to know if the nest themselves may signal something to other orioles.
The nests of the streak backed-orioles (Icterus pustulatus) are placed far out on the tips of branches in tall trees. These nests are unusual because they are extremely visible from great distances (to us, to predators, and to parasitic cowbirds), and their placement in such an obvious location is uncommon among birds (think how hard it is to find nests of most birds). It is thought that oriole nests are placed out on branch tips so that they are less accessible to predators, like snakes and arboreal mammals such as squirrels. Although this hypothesis may explain why many species of orioles place their nests in obvious locations, I am interested in testing if there might be some additional benefit to placing one's nest in a location where it can be easily seen by other orioles.
Interestingly, the female streak backed-oriole begins building her nest long before she lays eggs (often up to a month), and she only works on it a bit every day. However, this month-long investment is not necessary, as many females have been observed to build an entire nest in 4-6 days. My research focuses on why females build such extraordinary and obvious nests. I am testing the hypothesis that nest construction early on in the breeding season helps in establishing a nesting territory.The placement of this extremely visible nest might function like the placement of flags by explorers in the 1700's when they claimed land for their home country (e.g., Capt. Cook's placement of flags on 'newly discovered' islands in order to stake British claim). Part of our motivation in testing this idea comes from previous data that indicates that females sing very often while building their nests (more often, we think, then when they are away from their nests). This use of song while on the nest might be an additional way to 'claim' the real-estate for the female's breeding attempt.
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