Observing Plovers in Florida

white sand beaches of Little Gasparilla Island

white sand beaches of Little Gasparilla Island

The shell-strewn white sand beaches of Little Gasparilla Island, in Charlotte County, Florida (USA) are a plover paradise where (at this time of year) one can typically observe 5 plover species together for easy and close study. This past Sunday, February 16th, 2014 I was able to do just that as I participated in the Great Backyard Bird Count. Many shorebirds were amassed here including hundreds of Dunlin , Sanderling, Willets, Ruddy Turnstones, a handful of Western Sandpipers, and 5 species of Plovers.

Black-bellied Plover with Dunlin

Black-bellied Plover with Dunlin

The large Black-bellied Plovers (known as “Grey Plover” in Europe) dominated the beaches, second in size only to the taller Willets that over winter here.

Wilson's & Semipalmated Plovers

Wilson’s & Semipalmated Plovers

The other 4 plovers were all members of the “ringed” plover group that show bands across their breasts – Wilson’s, Semipalmated, Snowy, & Piping Plovers. Generally the darker-backed species, Wilson’s and Semipalmated, grouped loosely together and the lighter-backed Piping and Snowy Plovers stayed out on the whitest sand areas. The image above shows a Wilson’s Plover at left and a Semipalmated Plover at right. The two are similar but easily separated with experience or when seen together. That is what makes it so fun to visit an area like Little Gasparilla Island where all of these birds are visible on the same view. Semipalmated Plovers are very widespread and average smaller than Wilson’s Plovers. Semipalmateds show shorter bills which are thick-based and slightly conical, usually with hints of orange at the base in winter (more in breeding). Their head shape is comparatively more rounded and they show bright orange legs.

Wilson's Plovers - digiscoped by Ambrynn Julias 2/16/14

Wilson’s Plovers – digiscoped by Ambrynn Julius 2/16/14

By comparison, Wilson’s Plovers show long, heavy beaks that are thick near the tip. They specialize in feeding on fiddler crabs and other invertebrates at the dune’s edge and this large bill helps them to seize and eat their prey. They are larger and often appear slightly paler brown than Semipalmateds. Their legs are a fleshy pink, and their heads appear blockier as well. (See how the bill is comparatively long and straight at the base with a bulbous tip?) In the US their range is restricted to coastal portions of the Southeast and the Gulf of Mexico but they are resident through the Caribbean and along both coasts of Mexico, Central America, and northern South America.

Piping Plover digiscoped by Ambrynn Julias iPhone thru Leica APO Televid scope

Piping Plover digiscoped by Ambrynn Julius iPhone thru Leica APO Televid scope

The controversial Piping Plover breeds on sandy beaches in the heavily populated Northeastern United States and the Great Lakes. It’s an endangered bird and beach closures often occur where it nests. This is an unpopular situation for many in New England as it interferes with their recreational pursuits. There is likely no bird that has created more controversy than this little plover, because large stretches of beautiful white sand beaches have been closed in some of the most populated areas of the US in the heart of the New England summer when families and individuals often look to the beaches to stay cool!

Snowy Plover left & Piping Plover right

Snowy Plover left & Piping Plover right

On southwest Florida beaches, wintering Piping Plovers mix with the superficially similar Snowy Plover. Much like the Wilson’s & Semipalmated Plover pair, the Snowy & Piping are similarly sized and colored, but close views and side by side studies show easily distinguished differences. For example, the Piping Plover has a conical bill with an orange base and bright orange legs just as a Semipalmated Plover shows. Piping Plovers are also more “pot-bellied”, compared to the slimmer and more streamlined Snowy.

Snowy Plover digiscoped through Leica APO Televid spotting scope

Snowy Plover digiscoped through Leica APO Televid spotting scope

Snowy Plovers show a thin, straight black bill, and grayish legs (not orange like Piping). In the United States two disparate breeding populations of Snowy Plovers occur. The Western (Charadrius alexandrinus nivosus) averages darker backed than the Eastern (C.a.tenuirostris) is much lighter. The latter is resident in Florida and the breeding adults that nest in southwest Florida are extremely pale.

resident "Florida" Snowy Plovers copulating 2/16/14

resident “Florida” Snowy Plovers copulating 2/16/14

Interestingly, even by mid-February, while much of the US is gripped in the stranglehold of winter, resident “Florida” Snowy Plovers were courting, calling, making scrapes, and (as seen in the heavily-cropped image above) even copulating. All of the birds we saw engaging in this courtship behavior, were extremely light backed.

adult male "Florida" Snowy Plover - Leica digiscoped image 2/16/14

adult male “Florida” Snowy Plover – Leica digiscoped image 2/16/14

In breeding plumage the adult males develop a partial black collar, auricular patch, and forehead patch as above.

adult female "Florida" Snowy Plover - Leica digiscoped image 2/16/14

adult female “Florida” Snowy Plover – Leica digiscoped image 2/16/14

Adult female birds are similar but the markings average less distinct and more brown-toned. The pale-backed resident breeders, are also light through the long tertials which cover the flight feathers on the folded wing. This undoubtedly helps them to blend into the pale white sands here.

darker mantled Snowy Plover

darker mantled Snowy Plover

On this afternoon, we observed 10 individual Snowy Plovers – six light-backed birds and 4 darker-backed individuals leading to more questions. As example, are these darker birds all immatures or do some of the western nivosus birds winter in Florida? There are many examples of western species that move southeast to overwinter in the Florida peninsula including “western” Palm Warblers, Swainson’s Hawks, and (perhaps more relevant) Long-billed Curlews and “western” Willets. Nearly all of the wintering Willets in Florida seem to be of the western race actually, so there certainly is a similar precedent in the shorebird family.

field guides

field guides

In checking the popular literature, I became even more confused. I started with the general guides and found they were not helpful and seemingly in conflict with one another.

“Sibley Guide to Birds” (2000) – doesn’t address the existence of varying subspecies and depicts juveniles being uniformly marked on the dorsal surface and paler than both non-breeding adults and breeding adults.

“National Geographic Field Guide to Birds of North America” – show both nivosus and tenuirostris subspecies, but all but one depiction are of the darker nivosus. They depict juvenile Snowy plovers as mottled (not uniformly colored on the dorsal surface as Sibley) with dark centers and about the same tone as adult nivosus birds (not  darker). Females are depicted as having slightly less distinct dark collar, auricular, and forehead markings than male. They include a single depiction of a “Gulf Coast male tenuirostris” which is notably lighter in tone (2-3 shades) than the other birds shown which does seem to match the light birds I observed and photographed. So at least from this text one would assume these darker birds could only be western birds (although the truth is more likely there is not enough data to be conclusive).

“Crossley ID Guide, Eastern Birds” shows images of birds which are all much darker colored than the light birds seen and photographed at Gasparilla. In addition the “adult female” shows no hint of the dark markings on the face, breast, and forehead. This was in direct conflict with National Geographic’s depictions and my observations of the copulating pair and Crossley’s female looked much like the “non-breeding” depictions in the other guides. Also, Crossley showed a “non-breeding” bird which showed dark feather centers like the juvenile bird listed in National Geographic. Without a section for photo credits it was impossible to know where or when these images were taken.

“Kaufman Field Guide to Birds of North America” had the most simplified approach depicting only two images of Snowy Plover. One was labeled “summer male” and the other “winter male or female”. So again like Crossley, the Kaufman guide treated non-breeding and breeding female as identical, there was no treatment of subspecific variation as in Sibley, and the images both appeared more in line with dark nivosus birds.

dark Snowy Plover in Florida

dark Snowy Plover in Florida

So I turned next to the specialty guides. “The Shorebird Guide” by Michael O’Brien, Richard Crossley, and Kevin Karlson offered the most thorough treatment of the species with three pages of images and captions for ID, and 1.5 pages of text in the rear. The text acknowledged 6 subspecies worldwide, but indicated that nivosus ranged east to Louisiana and tenuirostris was found only in the eastern portion of the Gulf (from Louisiana east into the Caribbean). There were 10 images showing Snowy Plovers in total in the guide: 7 from California, 2 from Texas, and only one image of a nonbreeding bird from Florida. At any rate, here again almost all of the coverage was given to the nivosus subspecies and  the 1.5 pages of text addressed only life history, behavior and molt  without specifics on subspecific variation. No indication as to what a juvenile “Florida” Snowy Plover might look like sadly. 

dark Snowy Plover

dark Snowy Plover digiscoped with iPhone 4s thru Leica APO Televid spotting scope -2/16

The dark Snowy Plover digiscoped on Little Gasparilla Island above shows old, worn wing coverts with dark centers and dark centered crown feathers that some guides would suggest is a juvenile & others a non-breeding adult. Either way, it does appear that the mantle (back) feathering is mostly fresh feathers and they are comparatively very dark meaning the bird will remain a darker-backed bird. From this, I’d suggest that these darker-backed birds are likely not just darker juvenile plumaged tenuirostris birds, but western nivosus birds joining the resident Florida population in winter (assuming these birds would molt into their adult plumage color). Especially since it seemed (anecdotally) that the lighter birds I observed here were all engaging in apparent courtship with much vocalizing, territorial chases, making scrapes, and copulation while the darker birds were not. Additionally, all of the past nests I’ve found locally in Charlotte County were all very light birds, easily separable from these darker plumaged birds.

male "Florida" Snowy Plover - Little Gasparilla Island 2/16/14

male “Florida” Snowy Plover – Little Gasparilla Island 2/16/14

I can not be sure of this naturally without more observation, and there is nothing I can find in the popular literature that suggests the local juvenile Snowy Plovers would be darker or remain dark for multiple molt cycles. In the interim it is another fun mystery that perhaps only the birds themselves can answer… for now!