Rapid advances in miniaturized avian tracking devices have opened up opportunities to learn more about the movement patterns of birds. One group of birds that has long fascinated me is the gulls (Subfamily Larinae). There is limited literature available on similar studies tracking large gulls with satellite technology. Most studies have taken place with Lesser Black-backed Gulls in Europe (Thaxter et al. 2015, 2016, Juvaste et al. 2017), although I found two recent studies of Ring-billed, Herring, and Great Black-backed gulls in North America (Clark et al. 2016, Lato et al. 2021). I am also aware of ongoing work in the eastern U.S. with Ring-billed and Lesser Black-backed gulls; no doubt this type of work will continue to expand in the future.
Iowa, located in the Midwestern U.S., is a mecca for gulls with records for 21 species. The most numerous are Ring-billed Gull (a common migrant, rare breeder, and erratic winter resident) and Franklin's Gull (a fairly common migrant). Not surprisingly, most Iowa gulls are concentrated at the larger water bodies and along the Mississippi and Missouri rivers. Two locations stand out as hotspots for gull numbers and diversity: Saylorville Reservoir in Polk County (17 gull species) and Red Rock Reservoir in Marion County (16 gull species). Diversity and numbers peak in late fall, right before ice-up in November/December. When rare species occur, it sometimes appears that an individual moves between these two reservoirs, which many years ago sparked my interest in learning more about local gull movements. Our small group at Iowa State University (me, Carolyn Moore, Rachel Vanausdall) began this work in 2018, tagged our first gulls in 2019, and are continuing the work and expanding to include more gull species. All work is approved by the ISU Institutional Animal Care and Use Committee (IACUC protocol #20-177) and federal and state banding permits held by SJD. This Web resource showcases our initial efforts to learn more about the movements of these fascinating birds. Read on to learn more about the project!
Project objectives:
- Understand daily movements, dispersal, and survival of gulls in central Iowa.
- Document continental movements of gulls tagged in Iowa, including information about breeding, staging, and wintering sites.
Capturing gulls
My avian ecology group at Iowa State University does considerable work with wild birds, including efforts to capture them, band them, and affix auxiliary markers such as tracking devices and color bands. We have lots of experience catching all sorts of birds (mostly shorebirds) and can confirm that gulls are among the most difficult birds to capture! We've had the best success using 5-foot diameter bownets baited with bread, French fries, fish, and other goodies. We've also had limited success with a small net launcher baited with the same items, but poor success with a whoosh net and hand-held net gun. Hiding the device is the biggest challenge because the birds are keen-sighted and wary.
The tracking device
We affix a 15-gram solar-powered GPS-GSM tracker produced by Ornitela (OrniTrack-15 4G model) to each gull using a Teflon harness (see Clark et al. 2016). Thaxter et al. (2016) found no negative effects of the device or harness on gull survival or reproduction. The tags should last 2-3 years and are programmed to record ~50 locations per day. Data are downloaded daily via cell towers. The locations are quite precise (accuracy often <10 m) and the tags also record other data including altitude, direction, and speed.
Initial findings
![Glaucous Gull with tag [Click and drag to move] ](/cootjr/files/inline-images/GlaucousGull_1.jpg)
To date we have tagged >45 gulls in Iowa, mostly Ring-billed Gulls but also including Herring (n=5) and Glaucous (n=1) gulls. As the links below will illustrate, some of these birds cover a lot of ground! Individuals tagged in Iowa have been relocated in 20 states and 3 Canadian provinces; Montana and Nebraska were added in spring 2022. Daily movements of >100 km are quite common, especially during migration. We initially assumed the birds would move along the major river corridors, especially the Des Moines and Mississippi rivers, but that is decidedly uncommon. Many of the gulls departing central Iowa move more or less due south; very few follow the Des Moines River southeast to its confluence with the Mississippi River. The four large U.S. Army Corps of Engineers reservoirs (Saylorville, Red Rock, Rathbun, and Coralville) are big magnets for these birds, as suspected, and at least two individuals visited three of these reservoirs in a single day! In 2021 several Ring-billed Gulls tagged during late summer were resident at Saylorville and Red Rock through late December, which was completely unexpected. Several of these same individuals repeated this pattern in 2022, so it was not an isolated incident. But we still have much to learn and I will continue to update this page as appropriate.
Please click on the links below to view the travels of individual gulls. My daughter Lena deserves credit for naming them after team members, something unique about that individual gull, or character names from her science fiction readings. Each track represents the most recent ~3 months of information. Please note that we have filtered the data considerably so as to not over-clutter the maps and to keep the database files small. I will try to update these links monthly.
Ring-billed Gulls
Herring Gulls
**Tracks updated on 10 February 2024
Acknowledgments
Thanks are due to the many individuals who have helped with this work. Lena Dinsmore, Jon Moore, and Kevin T. Murphy helped with gull captures. We sincerely appreciate Sarah Borzo, Art Kern, John Penheiter, and others (Metro Park East Landfill) and John Roosa (Boone County Landfill) for allowing us access to their respective sites. Dan Clark kindly provided advice on how to capture gulls. Ramunas Zydelis of Ornitela has been especially responsive in answering questions about the tags and helped us in other ways. We also appreciate the many individuals who have helped us recover (or try to recover) tags from deceased gulls - Sabrina Chandler, Cameron Cox, Alexandre Dopkin, Frank Foidart, Cory Gregory, Curt Kempf, and Tom Thompson.
Literature Cited
Clark, D. E., S. DeStefano, K. G. MacKenzie, K. K. G. Koenen, and J. J. Whitney. 2016. Roost site selection by Ring-billed and Herring gulls. Journal of Wildlife Management 80:708-719.
Juvaste, R., et al. 2017. Satellite tracking of red-listed nominate Lesser Black-backed Gulls (Larus f. fuscus): Habitat specialization in foraging movements raises novel conservation needs. Global Ecology and Conservation 10:220-230.
Lato, K. A., D. J. Madigan, R. R. Veit, and L. H. Thorne. 2021. Closely related gull species show contrasting foraging strategies in an urban environment. Scientific Reports 11:23619.
Thaxter, C. B., et al. 2015. Seabird-wind farm interactions during the breeding season vary within and between years: A case study of Lesser Black-backed Gull Larus fuscus in the UK. Biological Conservation 186:347-358.
Thaxter, C. B., et al. 2016. Contrasting effects of GPS device and harness attachment on adult survival of Lesser Black-backed Gulls Larus fuscus and Great Skuas Stercorarius skua. Ibis 158:279-290.
For more information or comments please email Dr. Stephen J. Dinsmore, Iowa State University ( cootjr@iastate.edu ).
Preferred citation for this page:
Dinsmore, S. J. 2022. Iowa gull research. https://faculty.sites.iastate.edu/cootjr/iowa-gull-research