I’m a little late in starting this blog, as internet is limited here for both bandwidth and social reasons, but I enjoyed sharing my pictures from Costa Rica and I think it will be meaningful to do the same here. I am on Kent Island, a Bowdoin scientific research station in the Bay of Fundy, just off of the island Grand Manan. I’m here researching Yellow Warbler breeding behavior. While I am observing and gathering data on a variety of behaviors, such as incubation rhythms, egg laying dates, nest temperature, and nest building frequency, I am specifically interested in female vocalization on the nest. Recently, some ornithologists published a hypothesis that female Superb Fairy-Wrens incorporate a “password” into their incubation call that their chicks learn embryonically. The chicks the reciprocate this password when they beg for food. The password is a mechanism for detecting brood parasitism, which occurs when a parasitic species lays their egg in the nest of a host species, which then rears the parasitic nestling. Yellow Warblers are heavily parasitized by Brown-headed Cowbirds, so I’m doing research to see if the mechanism is widespread among host species. To do this, I am finding nests, recording the females on the nest, and then recording nestlings when they beg. Brown-headed Cowbirds don’t actually breed on Kent Island, but it is likely that if the behavior exists in mainland yellow warblers, it will also be part of the Kent Island population’s natural history. During the upcoming year, I am going to analyze the sonograms to see if there is any correlation between the two calls. I know you are already waiting with bated breath for the answer, but it will take a while. This photo is of a male yellow warbler all puffed up and cute. The males are distinguished from the females by their vibrant yellow plumage and the rusty streaks on their breast. Only the males sing, and do so to establish and guard territories as well as court females, but both sexes chip, or call. I can often use the males to find females, too, because the males mate-guard, meaning they follow the females around during foraging and nesting. They do this to make sure no other males copulate with her. Yellow Warblers are socially monogamous, meaning they nest and rear nestlings as a pair, but there is a lot of extra pair paternity from males that sneak into other males’ territories and copulate. It’s a constant battle that I’ve enjoyed watching unfold of the past two weeks.

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