An Opportunity for Franklin’s Gull Recovery at Agassiz National Wildlife Refuge

“What we can remember, we can bring back.” - Albert Naquin (Traditional Chief of the Isle de Jean Charles Band of the Biloxi-Chitimacha-Choctaw Indians)

Wildlife biologist Dr. Whitney Kroschel examining a nesting colony of Franklin’s gulls. Credit: Ashley Booth.

There are moments as an ecologist and conservationist that transport you to the wonder and magic of what used to be and inspire you to consider what could be brought into reality again. Happening upon a colony of 400 nesting Franklin’s gulls (Leucophaeus pipixcan) at Agassiz National Wildlife Refuge was one of those moments for me this summer. Refuge biologist Dr. Whitney Kroschel and I were surveying a large marsh at the Refuge when we spotted a cloud of birds swooping in and out of the cattail near an aspen island. As we moved closer, the birds grew louder, rising from their nests to defend their families and scare off the approaching threat.

A little over 100 years ago, approaching a colony of nesting Franklin’s gulls meant “… even at the distance of half a mile the harsh screams and rattling cries of the whirling mass of birds united to form a wild uproar that was very plainly audible….” (Roberts 1900). At Agassiz National Wildlife Refuge in northwest Minnesota, their nesting colonies once spanned thousands of acres and included as many as 300,000 adult gulls, making Agassiz the largest nesting colony of these gulls in the United States. However, numbers declined by 75-95% between 1968 and 2015 (Sauer et al. 2020). In the past two decades at Agassiz, numbers have varied wildly and in multiple years no new chicks survived long enough to leave the nest. These declines are especially concerning for Refuge staff, as birds like Franklin’s gulls can be indicators that the ecosystem itself is changing.

Numbers of Franklin’s gulls nesting at Agassiz National Wildlife Refuge from 1964 to 2022.

An adult and juvenile Franklin’s gull in a bulrush marsh at Agassiz NWR. Credit: USFWS.

Franklin's gulls are long-distance migrants that raise their young in floating nests colonies in prairie marshes. These small black, white, and grey birds have rosy pink chests, red legs, and red bills during the breeding season. Despite their small size, these delicate birds travel up to 10,000 miles each year between their wintering grounds in coastal South America and their breeding grounds in the upper Midwestern United States and prairie regions of Canada. After arriving at their breeding grounds, Franklin’s gulls build nests by layering dead plant material in the water around standing cattail and bulrush stalks. Creating floating nests and nesting in large groups helps protect eggs and chicks from predators. While breeding and nesting, Franklin’s gulls eat insects, seeds, and earthworms that provide the nutrition they need to raise healthy chicks. In the early 1900’s, farmers viewed these birds as extremely valuable because they protected crops by eating pests (Roberts 1900).

A young Franklin’s gull chick sitting on a nest. Credit: USFWS/Gregg Knutsen.

For US Fish and Wildlife Service staff at Agassiz, improving habitat for Franklin’s gulls and other migratory birds is challenging. Ecosystem issues like water pollution, buildup of sediment in wetland areas, and expansion of invasive cattail make habitat less ideal for Franklin’s gulls. These changes in habitat can impact food resources, nest site suitability, and predator access to nest colonies. As sediment builds up in wetland areas, plants like invasive cattail expand into these higher areas. If gulls nest near dry land or water levels drop, predators like mink and foxes can travel to the floating nest colonies and eat the eggs, young chicks, and even adults. To understand what is limiting Franklin’s gull nesting at Agassiz in recent years and improve wetland habitats, Refuge staff are sampling insect food resources, surveying sedimentation in wetland areas, and working to improve cattail management.

USFWS Directorate Fellow Ashley Booth examining a nesting colony of Franklin’s gulls. Credit: USFWS/Whitney Kroschel.

Our serendipitous encounter with nesting Franklin’s gulls this summer happened while on one of these surveying events. The birds flitted and swooped against the clear blue sky as we examined nests, and I could just imagine what the marsh must have been like in the not-so-distant past. And though their numbers are much smaller than they once were, the joy of finding these unique birds nesting was inspiring. That spark of imagining what used to be served as a timely reminder that the work we are doing now at Agassiz is helping to bring about a better future for Franklin’s gulls and other wetland wildlife. As Minnesota ornithologist Thomas Roberts said “besides being an object of great beauty and aesthetic value, [Franklin’s gulls are] eminently useful and beneficial bird[s] worthy of all the protection that can be afforded [them]”.

References

Roberts TS. 1900. An account of the nesting habits of Franklin’s Rosy Gull (Larus franklinii), as observed at Heron Lake in southern Minnesota. The Auk. 17:272-283.

Sauer, J.R., Link, W.A., and Hines, J.E., 2020, The North American Breeding Bird Survey, Analysis Results 1966 - 2015: U.S. Geological Survey data release.