The decline of the American Kestrel – and what we’re doing about it

American Kestrels (Falco sparverius) are North America’s smallest falcon and range extensively throughout the Americas. They tend to occupy open areas both in rural and urban environments, and require some sort of cavity for nesting and roosting, such as in a tree, a shallow cave in a cliff, a hole in a building or some other man-made structure. Their willingness to use nest boxes has been well documented.

Despite the generalist nature of this species, counts of long-term Breeding Bird Surveys, Christmas Bird Counts, migration data, and even nest box programs are showing regional population declines throughout the continent over the last century. Concerned investigators have hypothesized various causes of this decline but empirical support is unfortunately lacking. Our primary goals for this project are two-fold;

1) to develop student and citizen science based long-term research and monitoring efforts to better understand local and regional American Kestrel biology, especially in terms of conservation and population decline

2) provide nest boxes as a management strategy to increase cavity availability for nesting and roosting of the American Kestrel.

The Iowa Raptor Project (University of Iowa and Kirkwood Community College) and Brandon MacDougall, a doctoral student with the University of Iowa’s Department of Geographical and Sustainability Sciences, are partnering to develop a research project that focuses on nest box placement in an urbanized setting of the American midwest. The primary scientific objectives are to place nest boxes for the American Kestrel within open spaces along an urban-rural gradient, in order to compare occupancy, reproductive success, long-term demographic parameters of survivorship and dispersal, and possible long-term changes in life-history; such as sex ratios differences, as well as differences or changes in egg and chick size morphology. Local landscape attributes, such as the degree of canopy cover, land-cover type (i.e. Medium-density residential), or distance to water can be calculated and may play an important role in the selection of viable nesting habitat for the American Kestrel.

Keep your eyes out for these nest boxes around Iowa City!

This first year will focus on identifying locations within and adjacent to the Iowa City metro area to compare the various types of open space habitat landscapes that are present. Approximately 40 boxes were built and donated by a local contributor and another ten were donated through a local Eagle Boy Scout. The goal is to continue to expand the number of nest boxes in the research project to include another 150-200. This increase will allow for greater statistical comparisons, as well as student and citizen science volunteer participation through the building and monitoring of the nest boxes.

City Property Nest Box Locations
Next Box Locations

Volunteers will be recruited and trained to observe clusters of nest boxes in order to identify and monitor those that are active.  Monitoring will be done on a weekly basis. In the beginning, volunteers will monitor from a distance with binoculars. Iowa Raptor Project (IRP) Director, Shawn Hawks, will determine when it is safe for volunteers to check inside the box to get an egg (or clutch) count. American Kestrels are most prone to abandon during laying or early in the incubation stage, but the longer birds incubate, the more devoted they become to the nest. IRP volunteers will climb ladders to gain access to the nest after it is deemed appropriate. At approximately 20 days old, during the nestling stage, we wish to band the young. Another goal is to also band the adults. This project has been approved by the University of Iowa International Animal Care and Use Committee (IACUC) and the necessary permits for banding have been obtained from the state and the federal government. Monitoring will continue until the young have fledged; boxes will be cleaned in February of each year to allow for a new pair of American Kestrels each spring.

The data collected will be incorporated into Brandon’s doctoral work, but we plan to continue the project and collect data past his tenure. Thus, we hope to use the research data to help publish multiple papers in both gray literature reports and peer-reviewed articles, as well as keep the public updated through local social media, newspaper articles, and talk radio. We also expect to share this research with the international American Kestrel Partnership sponsored by the Peregrine Fund Inc. based in Boise, Idaho. We really appreciate your cooperation with this exciting project!

Shawn Hawks, Director, Iowa Raptor Project

Brandon MacDougall, PhD. Student, Dept. of Geographical and Sustainability Sciences


Scraping my first skull

A few years back I took a workshop at a National Association for Interpretation conference about making your own artifacts or scraping skulls. We sat in a fancy hotel conference room with boiled raccoon skulls and sharp scalpels placed before us and went to work. It was gruesome and fascinating.

A couple weeks ago, while completing a winter raptor survey with Shawn and IRP volunteer Adam Ciha, we came across a dead Barred Owl in the middle of F28 near Cemetery Road. We stopped to check it out. Shawn brought it to the van. It was still warm. The feathers were in magnificent condition. I expressed a desire to make this specimen my very first attempt at creating a skull artifact. Shawn reacted with mild surprise exclaiming, “Really?” I also wanted to save the wings because they were so beautiful. As a side note, the Iowa Raptor Project has a salvage permit from the United States Fish and Wildlife Service that allows us to have birds in our possession. We also have a salvage permit from the Iowa Department of Natural Resources.

Back at the Raptor Center, the first step was to put the bird in the freezer to kill all feather mites and any other hitchhikers. The second step was to cut off the head. But first I had to procure my instruments for this once again gruesome and fascinating task. Kirkwood Community College graciously supplied me with scalpels and I gathered an assortment of tools from home; a crochet needle, an awl, a nut pick, a dental scraper, tweezers, and scissors. I would also need a designated bone pot, washing soda, salt, hydrogen peroxide, tongs – and courage.

With an odd mixture of excitement and trepidation I took the bird out of the freezer. It was time to cut off the head. The owl’s neck appeared to be the width of a softball but it’s all feathers. The actual neck that I needed to cut through was only the size of my pinky finger! I was all ready to go when I realized the bird was frozen solid. I tapped my ingenuity and thawed the bird a bit by putting a pack of warm dry rice (affectionately known as a warm buddy) on the neck. When I removed the warm buddy, a happy accident occurred: voluminous amounts of feathers came out as well, being singed by the heat. Little by little I began to cut away some of the skin and muscle to find the place where the base of the skull joins the vertebrae. I was making slow progress, because if I lost my concentration, the scalpel would slice through my finger without hesitation. Trying to determine where to cut next, I wiggled the head a bit and it simply fell off. Well, that was easy.

The next step was to remove the skin from the head. I thought I was supposed to remove the eyeballs too. I began at the base of the skull and slowly cut and pulled and snipped the skin up and over toward the beak. Scraping out the eyeballs was so viscerally disgusting that I yelped a few times in dismay. Shawn popped in every now and then to check the progress and say some encouraging words like, “I know you’re having fun. Admit it!”

Just so you know, owl eyeballs look like the inside of a coconut and have the texture of an avocado. You also do not have to scrape them out. They will simply fall out after you cook it. Which brings me to the next step: boiling. I cooked the skull for about 45 minutes in a solution of salt and washing soda. I found out later that boiling the skull breaks down too much collagen and the bone becomes brittle. The best method is to slow cook it in a crock pot (preferably outside).


Now I am finally ready to wrestle the soft tissue away from the skull. As I began scraping, I discovered a fracture above the eye. The opposite side of the skull was also slightly crushed. I think this owl died from the impact of having its skull hit by a car. Even though the skull was damaged, I decided to continue this educational journey. Scraping, prodding and poking the brain tissue, the jaw muscles, the remaining eye tissue, etc., was, well, let’s just say it brings a unique nuance to the word “fun”. I really couldn’t figure out how I would have gotten the brain tissue out of the skull if it had not been damaged. Lucky for me I got to have lunch with my father-in-law, Dr. Holmes Semken, the following day. He has vast amounts of experience scraping skulls and collecting road kill. While enjoying our food, I brought up this experience and my questions about methods. I found out that you use a large syringe filled with water, inserted at the base of the skull and then injected, to flush out the brain matter. This makes perfect sense. Of course, he just happened to have some large syringes in a drawer somewhere that he gladly donated for future skull scraping endeavors. Looks like I will be trying my hand at making more artifacts in the future.


Oh, and I also found the perfect crock pot at Goodwill for $8.88. I am all set.

-Laura Semken, IRP assistant coordinator

The Growth of a Naturalist

Something interesting happened during the December Family Day. Laura had brought her fire pit from home and since there was a lull in attendance, myself and a few volunteers were sitting around keeping warm and conversing. A small family had just finished their self guided tour of the Raptor Center and the mom observed woodpeckers and nuthatches feeding on something in a bird feeder that was completely unfamiliar to her. She asked what this food was and someone explained that it’s called suet which is made up of primarily animal fat mixed with bird seed to provide high energy, especially during the winter months. Although satisfied, she had not walked a total of ten feet when she turned around and asked, “What does it taste like?”

I responded, “I don’t know, but let’s try it!” So about a half dozen of us, including the small family, took the suet out of the feeder and each of us either took a direct bite or pinched a bit off for a taste. Well, I’m sure it doesn’t take a bird brain to deduce that it isn’t exactly gourmet, more like “English bland” but great cuisine for birds, nevertheless. After expressing dislike with shriveled up faces and some commentary, I think we all promptly spat it out with disgust, but followed up with a mixture of smiles and laughter.

In nature, and throughout life, there are many opportunities to ask the same basic questions, to explore and discover, to be curious. From a cultural perspective, I (and I’m sure all the others) would have rather shared in other culinary cuisines representative of our regional and ethnic backgrounds instead of bird cuisine! But again, the basic question challenged us all to briefly step outside of our boundaries, try something new, and have fun with it!

In early November, a similar story of exploration and discovery occurred. Meredith Caskey, our Wildlife Camps and School of the Wild coordinator, asked me to lead a Raptor Center tour for Longfellow Elementary. The 6th graders were attending our School of the Wild program that week. When they arrived for their tour, they were very excited and full of questions. But before I tell that story, I need to explain a little about bird banding.

People who know me know that I enjoy working with animals hands-on. As a bird bander, I like to talk about banding and some of the reasons why we band birds, such as; to track movements and migratory connectivity, understand causes of mortality, and estimate survivorship and longevity. Banding information can also be used to track individual and overall population health based on collecting physiological measurements and sampling for diseases and contaminants. If you are on a tour of the raptor center, the most opportune time to discuss bird banding is when we reach Spirit, our Bald Eagle, and Kanati, our Peregrine Falcon. Both of these birds are banded. Kanati is even color banded.  Peregrine Falcons, like the Bald Eagle, have been recently delisted from the Endangered Species Act and Peregrine Falcon nests, especially in the Midwest and Great Lakes regions have been well documented, monitored, and the young are regularly banded to track survivorship and dispersal.

As a biologist, I, like many others, sometimes get excited about finding dead critters, especially birds. I get to figure out what the species is, and see if it is banded. As mentioned earlier that data is important for understanding both the biology of the birds and their population dynamics. Plus, it’s fun to report and learn the bird’s story! Earlier in the week I explained this weird fetish to the students’ teacher, and to my great excitement, a couple days later, the teacher came back with a surprise wrapped in a plastic bag tucked into her backpack. Apparently that morning, while hiking on the trail adjacent to the Coralville Reservoir, one of the young girls in the class came upon a rather large skeletal bone, which piqued her interest. After investigating further, to everyone’s delight, it turned out to be a leg bone of a rather large bird that included the feet (but rather desiccated), and a little bit of grayish-white feathers, as well as a large aluminum leg band! This group of kids hadn’t visited the raptor center yet, but they had already learned about bird banding first hand by taking part in banding passerines with Meredith. So when the class arrived, they were not only well informed but also greatly excited about their treasure. They immediately clamored, “What kind of large bird did this come from?”

I looked, saw the large No. 9 sized butt-end band, then looked closer at the feet and noticed that although they were rather desiccated, they were webbed. I deduced it to be a White Pelican. Later that afternoon I called the Bird Banding Lab and reported the band number, the location it was found, as well as how and by whom it was found so they could send a certificate of recovery and report the recovery information to the biologist who banded it.

It turned out that the bird was banded in early July of this past summer (2016) as a nestling (gender unknown) on Marsh Lake near Correll, Minnesota, which is the third largest colony in North America and well studied and monitored since 1972! (See this link for a bit of background).  After rapidly receiving an emailed electronic Certificate of Appreciation Recovery Award from the Bird Banding Lab and conducting a bit of background research, it was fun to share with the students using Google Earth as a tool to map the colony location and the approximate 331 mile direct flight route the bird might have traveled. Interestingly, one of the teachers used her Smartphone to obtain the exact recovery coordinate location where the banded leg bone was found. She used this information to further educate the kids. What a wonderful example of the use of modern technology to engage and excite both the students and teachers.

Longfellow Elementary students. The student in orange is holding the Pelican bone and the teacher is holding up the GPS coordinates on her phone.

These stories inspire me. I appreciate being involved in a team that actively engages students of all ages to explore and have fun in their surroundings, however weird, and live in the moment. As naturalists, sometimes we are rewarded by finding something a little rare. But more importantly, the more we can get people to engage and really learn what types of treasures surround us, like an uncommon plant or animal, or an unusual object or beautiful landscape, our goal is to inspire people to learn more about it out of curiosity and also connect with a heartfelt feeling to want to protect as well.

Shawn talking with Family Day visitors. Photo credit: Adam Ciha

-Shawn Hawks, IRP coodinator

Kestrel rescue at Rockwell Collins

During the late morning of November 30th, we received a request for assistance from Iowa DNR’s Johnson County conservation officer, Erika Billerbeck, as well as Rockwell Collins in Coralville.  An American Kestrel had somehow flown inside their building and the bird couldn’t figure out how to get back out. That evening, Laura and I met with Erika Billerbeck and Justin Schmit of Rockwell Collins to try and capture the bird. Unfortunately, due to logistics and scheduling, we weren’t able to meet up until after 8 P.M. This manufacturing plant is in operation continuously, 24 hours a day, with lights on and people working, but we could not locate the bird, probably because birds have night and day cycles just like humans and therefore decided enough was enough and went and found a roost for the night.

The next morning, we were able to lure the American Kestrel to a bal-chatri trap almost immediately, but unfortunately it didn’t get captured in the nooses. But the live House Sparrow within the trap used to lure the falcon, continued to pique its interest. Although with the passage of time, the falcon became more cautious. Fortunately, I had brought a 12 meter mist-net, and although we had to reposition it a few times to get the net high enough and maintain functionality, after another 60 to 90 minutes, the bird finally flew low enough to get caught.


This American Kestrel was a beautiful after-hatch-year male (of breeding age), weighed 100 grams, and was in good shape. After banding it and taking a few measurements, we let it go nearby in a natural field of restored prairie and wetland (basically, fine habitat for American Kestrels). Whether this is the bird’s home territory or not, we do not know, but we assumed it could be a good possibility. As I was driving away approximately 20 minutes later, I observed the bird kiting, or hunting, in another grassland area not too far away. So it had quickly resumed normal behavior.

This coming nesting season, I am hoping to begin an American Kestrel nest box project in order to identify occupancy, reproductive, and demographic parameters in relation to landscape and habitats. The nest boxes will be placed so that a comparison across urban landscape gradients to those that are rural can be assessed. Currently I am looking for funding to build the nest boxes, and I will begin to contact landowners to obtain permission to attach and monitor the nest boxes. I will also be looking for citizen science volunteers who would be willing to monitor clusters of nest boxes throughout the nesting season.

Rockwell Collins employee Justin Schmidt with Kestrel.

A huge thank you to Justin and the folks at Rockwell Collins for calling us and to the Iowa DNR to make capturing, banding, and releasing this bird back into the wild possible.  A special thanks also for the words of encouragement from many Rockwell Collins workers, and for the various ways different workers and staff also helped out. This was a great example of teamwork at its finest!

-Shawn Hawks, IRP Coordinator