Larus delawarensis (ring-billed gull)

The ring-billed gull is well known to most Midwesterners; it is our most common gull. In summer ring-billed gulls are found along the shores of the Great Lakes, from downtown Chicago to the most remote and empty shorelines of Michigan's Upper Peninsula. Many Midwestern children have thrown popcorn or bread crusts to ring-billed gulls, and have been delighted with the bobbing heads, the loud calls of yark yark, and the behavioral quirks of Larus delawarensis. In migration seasons the ring-billed gull can be seen on the Midwest's rivers, and in smaller lakes—often even in fields flooded by spring rains.

Identification of the ring-billed gull is more or less a matter of getting a good look at the bill, which has a prominent black ring encircling it near the end. Immature gulls can be more difficult to separate from the Midwest's other gulls (principally the herring gull, Larus argentatus), since the clearly defined "ring" does not develop until maturity; before that it appears like a black bill-tip—a juvenile feature shared with several other gulls.

Ring-billed gulls eat—well, pretty much anything: fish, crustaceans, insects, mice, worms, Cheetos . . . so the birds are officially "opportunistic" feeders, hunting and scavenging in outflow areas, on beaches, and in urban settings. Despite our sense that ring-billed gulls are highly active birds, studies indicate they spend between a third and one half of their time standing in place. Breeding occurs in spring, often on small rocky islands in massive colonies. We have seen one such island, on the Straits of Mackinac between Lake Michigan and Lake Huron, in summer—covered with a guano layer nearly an inch thick!

Midwestern range of Larus delawarensis
midwestern range

Larus delawarensis
ring-billed gulls under the Mackinac Bridge at sunset

Larus delawarensis
mature gulls

Larus delawarensis
the black "ring" around the mature bill is the defining feature

Larus delawarensis
a first-year juvenile on Lake Erie, in Ohio . . . note the pinkish legs, the mottled brown plumage, and the black-tipped pink bill

Larus delawarensis
a second-year juvenile . . . note the legs and bill beginning to turn yellow, the change in plumage colors, and the bill "ring" becoming defined

Larus delawarensis
a mature ring-billed gull in flight over Lake Michigan

References: Peterson 1980, Dunn & Alderfer 2009, Sibley 2014, Retter 2017, Pollet et al. in Rodewald 2018, Shupe 2019.

Kuo, Michael & Melissa Kuo (July, 2020). Larus delawarensis (ring-billed gull). Retrieved from the midwestnaturalist.com website: www.midwestnaturalist.com/larus_delawarensis.html

All text and images © , midwestnaturalist.com.