Tuesday, November 24, 2020

Ring-billed Gull

                                                       Ring-billed Gulls in Breeding Plumage

The Ring-billed Gulls are with us for the summer season.  They often make up a significant portion of flocks of gulls.  An adaptable, interesting species such as this is worth learning more about.  

Many people consider gulls dirty and unworthy of our consideration.  That is not true at all.  Look at the photos in this post and notice how clean these birds are.  Their whites are pristine as is the rest of their bodies.  I doubt if humans would remain this clean and this alert if living under the same conditions.  The only 'dirty' gulls I have ever seen (and they are few in number) are sick individuals.  The rest of the many gull species maintain their beautiful plumage and sharp eyes.  

Gulls are often discounted by beginning birders, perhaps because they can be difficult to identify.  I have learned over the years that they are definitely worth a second or third look.  They are very interesting and one can often get quite close to them.  They can be a good test of advanced birding skills.

                                                     Ring-billed Gull in Breeding Plumage

The Ring-billed Gull (Larus delawarensis) is classed as a 'Small White-headed Gull' in a group known as 'Typical Gulls'. It is the smallest of the white-headed gulls.  It may be the most populous gull in the world.  It is likely the most familiar gull in North America.  It is found mid-latitude in North America and winters to Middle America.  Vagrants sometimes stray to Europe, West Africa and Hawaii.  This species breeds across much of Canada from Alberta to New Brunswick mostly in the southern parts, but also somewhat below the US/Canadian border and along the shores of the Gulf of St. Lawrence including Gaspé and Anticosti Island.  It is a full-time resident around the southern Great Lakes and in areas of Washington State and Idaho.  During migration it can be found in southern B.C., northern Ontario, in Newfoundland throughout the island and along the coast of Labrador.  As you can see, this gull gets around!  Here in New Brunswick they arrive in April or May and stay until November or December.  The photo below shows an individual which has learned that food is available on our crow feeder and has come every fall for several years now.  It will stay for a few weeks depending on weather (late November at time of writing).    

                                                   Ring-billed Gull in Non-breeding Plumage

The Ring-billed Gull is a 3-cycle gull.  It takes 3 years for it to become an adult and it goes through several plumage changes and other anatomical changes during this development.  This species goes through the following stages with changes in appearance happening gradually throughout the changes:  juvenile, first cycle, second cycle, third cycle, adult non-breeding, adult breeding.  No wonder gulls can be difficult to identify!  The 3 photos above show adult gulls in breeding and non-breeding plumages.

The Ring-billed Gull is a medium-sized gull with a pale gray back (mantle), yellow legs, black ring on a yellow bill, and pale yellow eyes.  Its head, neck, breast and belly are white.  In breeding plumage the pale yellow eye has an orange-red orbital ring.  In non-breeding plumage this becomes black.  The adult has black wing tips with mirrors (white spots) on P9 and P10 (primary wing feathers 1 and 2).  The underwing feathers are white.

The juvenile plumage is a pale gray-brown overall with a white tail with a broad black distal tail band.  The bird is boldly spotted and mottled with brown over a white background.  The eye is black.  The bill shows a pink base with a black tip.  The legs are pink.  First, second and third cycles are gradual transitions from this juvenile plumage to the adult plumage.  The details of these changes are too detailed for this post.  A good place to study these in detail is the book by distinguished larophiles, Steve N. G. Howell and Jon Dunn, Gulls of the Americas, Hougton Mifflin Company, Boston, 2007.

                                            Ring-billed Gull in Adult Breeding Plumage

Here in New Brunswick you won't likely mistake this gull from other gull species.  Rarely a Common Gull arrives from Europe and it is very similar to the Ring-billed.  Out west one has to distinguish it from the California Gull.  

Ring-billed Gulls usually nest in colonies often with other species of gulls and sometimes terns.  They often choose islands in lakes.  Their nest is a depression in the ground lined with grass and small sticks.  Two to four olive to brown eggs spotted with lavender, brown or gray are incubated for 21 to 28 days by both adults.  Although this species often feeds by scavenging, it eats fish, insects, rodents, young birds, and grains.  We have all seen them scavenging on garbage dumps, landfills, and they especially love ploughed fields.  We regularly see large flocks on the fields of the Keswick flats.  They will even grab food off water surfaces while in flight.  This species is sometimes called the 'fast-food gull' because it hangs around fast food restaurants looking for handouts.  

In the 19th century this species was hunted for its plumage with drastic affects on population numbers.  As we all know, it has thankfully rebounded well.  The results of an experiment done with 2-day old Ring-billed Gulls are very interesting.  They showed a preference for magnetic bearings in the direction of their fall migration.  More is being learned in recent times about how birds migrate successfully.

Take a close look at the gulls near you the next time you are out and appreciate how beautiful, successful birds they are.

                                        Ring-billed Gull Showing White Wing Linings


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