Wednesday, December 23, 2015

Royal and Elegant Terns

A year ago I wrote about the identification the larger orange-billed terns in southern California (see ID: Elegant, Royal, and Caspian Terns). That ID article showed birds in flight.

Recently I walked out on the beach near the Oceanside harbor and encountered a flock of about 40 terns resting on the beach. Most were Royal Terns as expected for this time of year. A few were Elegant Terns--it's getting on the late side for them.

Royal and Elegant Tern
One of these birds is not like the others.
Most of the birds above are Royal Terns. The bird on the far right is an Elegant Tern. Let's take a closer look at two together.

Royal and Elegant Tern
Elegant Tern (left) and Royal Tern (right). Oceanside, California. November 8, 2015. Greg Gillson.
There are 3 marks to note on these non-breeding terns on the beach: size, bill, crest.
  1. Royal Terns are a bit larger than Elegant Terns.
  2. The bill on Royal Tern is stout and dark orange. The bill on Elegant Tern is thin and down-curved and often yellower.
  3. The crest on Royal Tern is short and bushy, straight back from the eye. The eye is usually isolated from the crest and the crown above the eye is usually extensively white. The longer crest on Elegant Tern encircles the eye, starts on the crown above the eye and wraps down the nape.
Royal Tern
Royal Tern
Both Royal and Elegant Terns have fully black crowns (including forehead) in the breeding season (April-June?) and thus are even more similar looking then.

Elegant Tern
Elegant Tern
Royal Tern
Royal Tern
Elegant Tern
Elegant Tern
Royal Tern
Royal Tern
Elegant Tern
Elegant Tern
Elegant Tern
Elegant Tern
Elegant Tern
Elegant Tern.
Royal Tern
Royal Tern
Royal Tern
Royal Tern
Elegant Tern
Elegant Tern