16 tern species have been recorded in Texas, but as shown below only 9 of these are regular. 6 of these are present year-round on the Texas coast: Caspian, Royal, Sandwich, Forster’s, Gull-billed and Black Skimmer. The Common and Black are primarily migrants through Texas during fall and spring migration, however a few Common are present on the Texas Coast in winter. The Least is only present during summer.

Caspian Tern (“Prince Caspian”)

Weighing in at a hefty 1.5 pounds, the Caspian Tern (or “Prince Caspian” as I’ve dubbed them) is the largest in the world. Compared to other terns it sports a hefty neck, head and bill and has a wide wing with a shortish tail.

In basic plumage the Caspian usually retains at least a “salt-n-pepper” cap.
The Caspian has a sturdy, somewhat triangular bill usually with a dusky tip.
The bill on the smaller Royal is more slender and slightly down-curved.

Bill Color

The color of the bill is often cited as one of the first field marks to differentiate the Caspian from the Royal. On the majority of birds this works well. However, I find that the color of both species can appear more orangey or more red, depending on age, lighting conditions and breeding state of the birds. Therefore, I suggest that the bill shape can be a more reliable field mark.

Both birds in this photo are Caspian, but the left bird’s bill is more orangey, while the right’s bill is more reddish.
In alternate (breeding) plumage the Caspian’s black cap is complete, but lacks the longer shaggy crest of the Royal.

In Flight

In flight the Caspian is a sturdy, almost gull-like tern, with a thicker neck, sturdier bill and wider wing-base than other terns.

In comparison to the Royal, the Caspian usually shows more extensive black on the underside of the outer 5 or 6 primaries. The phrase I use to remember this difference is “Prince Caspian’s black reign”. (Caspian on the right, Royal on the left in the photo). The Caspian often flies with its bill pointing downwards.

Both terns in the photos above are Caspian.

The Royal Tern in contrast sports the “friar Tuck” look during the winter months of basic plumage.

Here a Royal is bracketed by 2 larger Caspians. Note the more triangular bill of the Caspian, and the slender, slightly down-turned bill of the Royal.

Royal Tern (aka “The Royal Carrot”)

The Royal Tern (the 2nd largest) is very common year-round on the Texas Coast. It’s rolling “koorrick” call is one of the iconic sounds of Texas beaches. As a memory aid I’ve dubbed it “The Royal Carrot” for the carrot-orange bill it usually exhibits. As detailed above the Royal is usually only confused with the Caspian, although the rare in Texas Elegant Tern should also be considered.

In alternate plumage the Royal shows a black cap with a shaggy crest at the back. Its size (larger than Sandwich and smaller than Caspian) is also a good thing to note.

In basic plumage the Royal is best remembered for its “Friar Tuck” look when the front of the cap turns white, but the black is retained in back and on the edges.
In flight the Royal shows less black in the under-wing than the Caspian, has more slender wings and usually has a carrot-orange bill.
The body of the Royal is about the same size as the Laughing Gull.
This photos shows an example of how a Royal’s bill can occasionally appear reddish.

Sandwich Tern (“dipped in mustard”)

The 3rd largest tern is the Sandwich Tern. Regretfully it wasn’t named for its “mustard-tipped” bill, but “dipped in mustard” is a good mnemonic for the black bill with a yellow tip.

In alternate plumage the Sandwich sports a black cap with a shaggy crest in back. Its yellow-tipped, black bill is usually noticeable year-round. Sometimes in peak breeding plumage the Sandwich may show a faint pink hue as in the photo above.

In basic plumage the Sandwich is another that sports “the Friar Tuck” look.
In flight the slender wings and sleek body of Sandwich are noticeable.

(See page 2 of Terns)

(See page 3 of Terns)