Acadian Flycatchers and the Health of the Eastern Hemlocks

Three Acadian Flycatchers, one parent and two juveniles. Photo Credit / Megan Napoli
Three Acadian Flycatchers, one parent and two juveniles. Photo Credit / Megan Napoli
Three Acadian Flycatchers, one parent and two juveniles.
Photo Credit / Megan Napoli


SC Staff Writer


Megan Napoli, a graduate student under Dr. Master at East Stroudsburg University, is doing her master’s thesis on the Acadian Flycatcher. The Acadian Flycatcher is a bird in the flycatcher family.

This bird lives in association with streams and wooded areas. In Pennsylvania, the Acadian Flycatcher is most strongly associated with the Eastern Hemlock, and it lives within the lower branches of these trees.

In reference to her research, Napoli said, “What we are looking at is the Wooly Adelgid. They’re this type of insect that is really devastating the Easter Hemlocks in this area at a really fast rate.”

According to Napoli, “The Wooly Adelgid sucks the life force out of these Hemlocks and they will die within a couple of years.”

When the insects begin to attack the Hemlocks, they begin at the bottom branches and then move toward the top of the tree. The main purpose of the project is “to look at how this is affecting the population, if it is affecting it at all.”

This study is being done as a follow-up to a very similar study done several years ago by another graduate student under Dr. Master. Napoli stated that during this previous project, “they looked at almost the same sites that we are looking at now.”

This will allow Napoli to look at changes in the sites between then and now.

The Acadian Flycatcher was chosen for this project because, as Napoli said, “It is like an indicator for the health of how this whole forest setting is doing.”

Since the Acadian Flycatchers are so dependent upon the Hemlocks for their nesting and breeding, then they can be used to measure the health of the trees and, by extension, the forest.

Napoli strongly believes that these birds “can show us how important the Hemlocks are for the area, because not only are the Hemlocks important for the Acadian Flycatchers, but they are also important for the Blue Headed Vireos, the Black-Throated Green Warblers, Blackburnian Warblers, and many other species that are closely associated with and dependent on the Hemlocks.”

Another reason that the Acadian Flycatcher is the main point of focus for this project is that they are easy to study. An example given by Napoli is that “Blackburnian Warblers nest really high in the tree, whereas Acadian Flycatchers nest really low, so it is much easier for a researcher to see how the Wooly Adelgid is affecting the population.”

One interesting preliminary result that Napoli shared is that “the Acadian Flycatchers in certain sites are adapting to use deciduous trees such as American Beech, Yellow Berch, Black Gum, and Sugar Maples.”

This is an interesting trend that was not seen in the previous study done on these birds.

It is currently unknown what attracts the flycatchers to the Eastern Hemlocks. One theory held by Dr. Master is that the way Hemlocks are structured allows debris to fall and accumulate on top of the branches, which forms structures that have a similar appearance to the Acadian Flycatcher nests. This serves as a camouflage for the nests that are built within the trees by these birds.

According to Napoli, “These birds are doing successfully in the deciduous trees as well, but it is just in one site that we are seeing this.”

When looking for Acadian Flycatchers, Napoli found that there were many areas where the bottom of the Hemlocks were heavily affected by the Wooly Adelgid, but the rest of the trees were relatively healthy.

In these same areas, there were many healthy and successful Acadian Flycatchers several years before, when the study was first conducted. “This looks bad,” stated Napoli, “Where did they go? There are no Acadian Flycatchers, and this looks bad, like they are disappearing.”

“But what we are seeing,” Napoli continues, “in the areas where the Hemlocks are completely destroyed and the branches are all dead and where the trees are falling down, like the one site I had, Dunfield Creek, these are the areas where the flycatchers are starting to go into the deciduous trees.”

When commenting on the outlook of the Acadian Flycatchers with concern to the Wooly Adelgid, she stated, “It looks like they can adapt, but this is just one bird species. Who knows if the other bird species can adapt?” Megan has found 55 nests in her research to date, and 75 percent of those nests have been reproductively successful.

Napoli hopes to be done with data collection by next August, at which point she will begin to write her master’s thesis. Her thesis will be finished and presented in the spring of 2015.


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