It was a hot, muggy day at Fern Ridge Reservoir, a US Army Corps of Engineers managed reservoir just outside of Eugene in the Willamette Valley region of Oregon. Two of my coworkers and I were loading up a truck with gear, and rigging up a small boat called a Zodiac, which slightly resembled a blow-up raft that you could find in the sporting goods section of a Wal-Mart (though much more structurally sound). We loaded up the truck and boat with an assortment of items that included a battery operated drill, three hard hats, a metal clip board, and five or six elongated bird boxes with half-moon shaped openings. The reason for such gear was the fact that we were preparing to undergo what would be my fourth purple martin nest box survey as an AmeriCorps Volunteer with the Environmental Stewardship section of US Army Corps of Engineers.
Before I get too much further into what goes on during a purple martin nest box survey, I feel I should provide a little background information as too why the Corps of Engineers actually does such a thing. It all starts with the Corps-run operation known as the Willamette Valley Project. This project is based on 13 reservoirs within the Willamette River Drainage system. Starting in the south outside of Cottage Grove, Oregon and continuing north to the Detroit Lake east of Salem, Oregon. The main goal of this project is flood reduction, and with that comes an array of other objectives such as irrigation, hydroelectric power, improvement of water quality, environmental stewardship, and enrichment of wildlife. The last one is where the purple martin surveys come in.
The purple martin is a species of bird from the order of Passeriformes (perching birds) and is the largest species in the swallow family. Purple martins are insectivores, meaning they catch and eat insects from the air, and like many other swallows, they nest in tree cavities and man-made nest boxes. The purple martin is a unique species due to the fact that throughout their present range they rely on man-made nest structures. In the Eastern portion of the United States, purple martins have relied heavily on man-made nests since before European colonization. Native Americans would place hollowed-out gourds around the settlements to provide nesting areas for the martins. After colonization, settlers continued this effort and today purple martins nest almost exclusively in man-made structures in the eastern portion of their range in North America. In the West, purple martins do not rely solely on man-made structures, but with the reduction of natural nesting structures the boxes the Corps maintains have become more important. Over the last century a decline in the population along the Pacific Coast region has been observed. Potential factors for the decline include habitat loss, removal of snags during logging operations, and competition with European starlings for nesting sites.
The population estimate for the region (including California, Oregon, Washington, and British Columbia) was estimated to be 3,500 pairs in 2005. The original regional management objective was to reach more than 6,000 pairs by 2010. While there has been an increase in breeding pairs, this goal has not quite been met, but conservation action continues with the hope of bringing this beautiful species of bird back to a healthy population in the Northwest.
The Corps of Engineers environmental stewardship section, which is based at Fern Ridge Reservoir, is one such group that contributes to the study and actively manages of purple martins. As a wildlife biology student, I feel very fortunate to have been a part of the team as an AmeriCorps volunteer during the Summer of 2013, and contribute my service to such a great wildlife-related cause. AmeriCorps is known for outstanding service to human communities, and I feel honored to have been able to provide service to natural communities as well. In a way, purple martins have also become part of human communities due to the fact that people have done so much for them throughout history.
Now that a little background has been presented, I’ll get back to what a purple martin nest box survey actually looks and feels like in action. On paper, the concept of the survey seems relatively simple, but speaking from experience, it can be quite difficult logistically.
Purple martin nest boxes are located on poles placed throughout Fern Ridge Reservoir. To maintain safe places to nest some type of predator guard is required (usually in the form of sheet metal wrapped around the poles), and what better way to keep land-based predators out than by surrounding them by water. The process begins with boating out to various poles that are marked on a map. This sounds like it should be the simplest of tasks, but for the Fern Ridge survey, it took my coworkers and I two tries with two different boats due to the substantially low water levels of the reservoir this year. During one particular eight and a half hour day, half of our time was spent trudging through knee-deep water pulling the boat through mud, bull rush and reed canary-grass to reach our destinations. Add 95 degree weather to that equation and you’ve got yourself one heck of a fun field day!
Each pole has a series a nest boxes attached to it, all arranged in columns on two-by-fours that are known as ‘gangs’. The direction that each gang is facing is noted on the data sheet, so that we can properly record our findings in each box. Once we arrive at a nest box pole, the next step is to secure a ladder on to the pole, climb it, and take each next box down. This is generally doable without issue, but caution is always a must as falling off a ladder would require some lengthy paper work and needless to say injury. Naturally, the swarms of angry parents flying around can make for a distraction during this high stakes operation.
After all of the nest boxes are safe and sound in the boat, the study truly begins. This is the stage of the survey where we have to be the most careful, as we actually have to handle the purple martin chicks in the boxes in order to gauge how old they are. We have to act quickly so as not to disturb the nesting process too much, and because some of the chicks are at the age when they are ready to leave the nest (this usually happens sometime around 28 days). If a chick leaves the nest when a box is on the ground, it will not be able to achieve flight without being held in the air. I personally had to help chicks fledge on several occasions, and while it went smoothly, it can be dangerous as the chicks can be injured.
In the end, after many long days of hard work in the heat and knee deep mud, we leave with a few simple, yet crucial pieces of information. This data provides insight into how this species is doing and where future management actions should go for recovery and management of a beautiful species that is in need of our help and protection. If organizations such as the US Army Corps of Engineers continue to study these birds, and the public takes action towards caring for the environment, I believe the purple martin can easily return to a healthy population along the Pacific Coast. I also believe that the successful recovery of one species leads to success for many others, as wildlife scientists are able to take and use examples of proper management and stewardship.