The longest crest

 

A large group of Elegant Terns (Thalasseus elegans) roosting on floating oyster bags in Tomales Bay on 5 August 2012.  In a small sailboat, we were able to approach and glide by quietly.

The genus Thalasseus means "creature of the sea."  It includes six species known generally as crested terns.  The Elegant Tern has the longest (or shaggiest) crest — in all of these photos, look for the long black spiky feathers extending backward behind the head.

Note also the very long bill, with a strongly curved upper mandible.  The bill color varies quite a bit from yellow to orange-red.

 

Although I only had one pass at these terns, a few interesting things showed up in the photos.

Elegant Terns can show a diffuse pink wash on their underparts (similar to Roseate Terns) — see bird on right below.

 

Leg color in Elegant Terns is typically black, rarely red.  There were a few individuals with red legs in this flock.  Can you find one in the next image?

 

(It's the bird near center, just below and to the left of the gull in the background.) 

Instead of uniformly pale gray upperparts, juvenile Elegant Terns often have feathers with dark gray centers, giving them a scaly appearance.  Can you find a juvenile in the photo below?

 

(The most obvious one is the second bird from the right.)

Numbers of Elegant Terns peak in central California during late summer.  They breed in Mexico and southern California, then disperse northward along the coast after the breeding season.  [90-97% of the breeding population nests on one island in Mexico, Isla Rasa.]  Most Elegant Terns will leave California by November and spend the winter from Mexico southward.  Catch them while you can!  

(Good places to look for Elegant Terns near Bodega Head include the South Jetty near Campbell Cove and the tidal flats inside Doran Beach.)

P.S.  Congratulations, Curiosity!  Welcome to Mars!