Searching Appalachian Old Growth Forests for Cerulean Warblers

Spring in the Southern Appalachians is a special time. The wide array of wildflowers and deciduous trees are emerging from their winter slumber. The forest is filled with the incredible sights and sounds of neotropical migratory songbirds that travel from their wintering grounds in Central and South America back to their breeding grounds in the Southeastern United States. In May and June, dawn is welcomed with a chorus of songs from colorful warblers, tanagers and buntings, among others. Many of these species, unfortunately, have been in decline for decades as they suffer from habitat loss across their range. Their abundance is especially and directly tied to the need to protect and restore forests.

Take the cerulean warbler. This beautiful, bright blue bird needs Appalachian old growth forests to sustain and grow its populations. It is important, therefore, to learn all we can about the ecological relationship ceruleans have with old growth forests across the landscape to address the recovery of this species of conservation concern.

Image

ps50ace-iStockphoto

Furthermore, it is imperative we do all we can to protect the forests from being lost, fragmented or converted due to development or management practices that put these special places at risk. Nowhere is this more critical than in our national forests which sustain the most significant proportion of old growth forests in the East. The national forests of western North Carolina are a biodiversity hotspot and provide a stronghold for cerulean warblers.

Surveying Cerulean Warblers: Historically

For decades, our understanding of where and how migratory songbirds utilize the national forests relied exclusively on point count surveys. These surveys involved listening and looking for the birds from easily accessed trails and forest roads. Even in our decade-plus of surveying for cerulean warblers—which involved going deep into the forest hours before dawn—single observations required hours and hours to collect, and opportunities to cover much ground were limited.

Image

Ben Prater-DOW

If the birds weren’t seen or heard, it was assumed they weren’t present. Forest managers relying on this infrequent detection within the national forests would claim the impacts of large-scale logging in mature and old growth forests to be inconsequential to ceruleans. But they did not have the whole picture. To truly understand cerulean ecology, we must systematically survey within old growth forests, which are often not easy to access. To overcome this inherent challenge and historic sampling bias, we are using new technologies to more carefully census birds within the heart of the habitats they use.  

Surveying Cerulean Warblers Using Today’s Technology

This spring, Defenders of Wildlife partnered with the National Parks Conservation Association, MountainTrue, the Center for Biological Diversity, the U.S. Forest Service and local volunteers to help get a two-year cerulean warbler and avian diversity survey project off the ground. The project occurs in the Craggie Mountains within Pisgah National Forest, N.C. These mountains are known for their rugged terrain, steep slopes and mature forests. Our collective goal is to help fill knowledge gaps and provide valuable data for future decision making in forest management and conservation efforts.  

To achieve this goal, we are using the latest technology: acoustic recording units (ARUs). These units are mounted to trees within suitable habitat and record bird songs at dawn and dusk every day for weeks at a time. This reduces the number of person-hours needed to survey and significantly increases the amount of data collected that can then be analyzed to detect the presence of ceruleans.  

ARUs allow us to provide more conclusive data on the presence of ceruleans and better guide management activities to avoid impacts. They also allow us to understand the presence of the full suite of species associated with similar habitats and in decline. ARUs record it all and powerful software analyses can help paint a picture of the entire guild of songbirds found within these areas of the national forests. So, there is plenty more to discover and learn from this information.  

Image

Ben Prater-DOW

For example, we also hope to examine the frequency and duration of cerulean warbler songs over time. Many male songbirds sing loud and proud to attract a mate. Once they are successful, and hopefully breeding, their calls change. They sing less often and focus their calls on defending their territory. By tracking if and how cerulean warblers’ calls change over time, we may understand if these birds are breeding successfully. Just knowing the species is present is not enough to evaluate whether the population is healthy.  

You Can Help Save Songbirds Too

The conservation of birds has always depended on passionate community scientists who are eager to explore the natural world and track the presence of birds in the landscape. As technologies and tools have changed, the ability to rely on data collected by community scientists has become more useful and essential to understanding the trends in songbird populations. Bird watching clubs and students are already helping in the cerulean surveys. It is magical to see someone’s appreciation for birds lead to good science that can help protect the species we all care about.  

The next time you venture out in the spring be sure to take one of the awesome mobile phone applications, like Merlin, to help learn about the birds and detect their beautiful songs. It is amazing to think how something as simple as holding your phone up in the woods can provide important data to conserve wildlife.

Buckle up, we're virtually hitting the road this summer! Learn about the other amazing species in North Carolina we are fighting for and check out cool places you can visit during your next trip to the state.