Elegant Tern (Thalasseus elegans) parent bringing a fish in his/her beak to her youngster on Morro Strand State Beach, Morro Bay, CA. This is an anchovy of around 10 cm.
This photo is not a sharp as the Fool Island Pigeon Guillemots, but the field characters of Pacific Sand Lance body and tail are distinctive enough for a positive ID. A rhino's exposed culmen is pretty close to that of pigeon guillemot (33 mm) which makes these three sand lance about the same size class (15-18 cm). I see one fish on the left side of bill (silver white belly forward) and two on the right side of the bill with their bellies touching. These sand lance would be a bit wiggly as the rhino flew by and you can get a little sense of that motion given that none of the fish are in the same position.
The pictures don't get much better than these and these very good pictures are fantastic in training the eye to see more in bad conditions or with fewer field marks. You can see the guillemot's lower bill under the right operculum of the sand lance. This particular hold on a fish is also more particular to guillemots than most other bill loaders. The smooth scaleless skin of the sand lance with the dark to light contrast and blue black hues are quintessential field markings. It also worth noting that the bright white belly is opaque and without any transluscence. And finally the small and strongly forked tail could probably be enough to ID even a silhouette as a sand lance because none of the gunnel or priclebacks with this elongate form have such a tail. I'd estimate the fish size/s around 5 to 6 culmen's length or 15-18 cm.
The wonderful resolution of this photo allows a confident identification of a clupeid because you can see distinctive scales on the back and in fact a few rough spots were scales have popped out through the trauma of capture and transport. Although the head is completely out of view the elongate fusiform body with only modest tapering in the peduncle suggest it is probably a Pacific herring or sardine and not one of the threadfin herring or shad which are relatively deeper bodied and taper a bit more in the peduncle. Royal Tern exposed culmen run in the 63-65 mm range, so this fish is probably at least 13 cm long.
Review the original posting to get some great field marks regarding Elegant and Royal Terns. I have also seen Caspian Terns with the unusually red or red mottled legs as well.
This week last year a clupeid in southern California met its demise in the bill of a Caspian Tern. This clup has its mouth partially open which changes the shape of the head but given the resolution of the photo you can't zoom in to see the fluting of the telescoping mouth. The strongly forked clear tail, the apparent absence or in fact inconspicuousness of the rest of the fins, the size and position of the eye, and the blue gray hue of the top also support a clupeid, probably a sardine, maybe a herring. This particular fish would probably be around 14 cm long.
It appears in the original posting of this photo that it was a courtship feed. This site (Ballona Wetlands, Playa del Rey, CA) is about 20 miles as the tern flies to a breeding colony at Bolsa Chica, but Caspians have nested on dredge spoils in other parts of the greater LA region as well. Clupeids are rich in lipids for their body size, so this a great courtship offering.
The key field marks on this fish identifying it as probably a Topsmelt (Atherinops affinis) is the relatively flat back, larger and more stiffly opened tail, conspicuous pectoral fin, and the smaller pointed head. The general stiffness of the body and white silver belly, silver striped side and green bronze dorsal surface also fit with Atherinidae ID. The abdominal anal fin is a shadow in the bill of the Caspian Tern which would be another great field mark. Because the fish is not showing an hint of blue hue it is probably not a Jacksmelt (A. californiensis), but Grunion (Leuresthes tenuis) can not be eliminated (by me at least). One other notable question about this photo is the black line streaming from the bill that seems to originate from the fish's belly. I would estimate this fish at 14-15 cm.
In this photo the key field mark of the pale contrasting belly of sculpin in very clear. The head is under water, but the the body shape and fins are all arranged in formation to be one of the sculpin species that has a clear space on the penducle between the 2nd dorsal fin and the caudal (tail) fin. The fins are all erect and flared as the fish is very alive and struggling. These would start to collapse usually following death of the fish. Note the lateral line is conspicuous enough to see running low along the pale side. The pectoral fins are flared out and pink gills are viewable under the operculum. This is usually the only red color seen on sculpin as they don't bleed even when skin is ripped away (typically on the penducle). Fish size is probably 7-8 cm.
Here is a Pigeon Guillemot with a sculpin in British Columbia which probably makes it Cepphus columba adianta which has on average a slightly smaller culmen (34 mm) than the guillemots of Oregon (35+ mm). Such a tiny difference is meaningless however in making field estimates of a couple cm. This sculpin is facing away from the viewer and is probably 6-7 cm long. Note the large pectoral fins and how the tail hangs down from the head. Sculpin held in this position (bill grabbing the sides) can appear floppy in the back end, whereas a dorsal-ventral hold they are a little stiffer bodied.
Given this photo was taken in Oregon late in the breeding season it is most likely Cepphus columba eureka, but the range between culmen length is not that great across the subspecies of Pigeon Guillemot and is reasonably estimated to be 35 mm. This fish is little more than 2 bill lengths or 7-8 cm. It is a great example of a sculpin, probably a Pacific Staghorn Sculpin, with the large head and rapidly tapering body. The sculpin is facing away from the viewer and the pectoral fins are the two things tapering away at 45 degree angles. These fins commonly are erected away from the body. If the fish were facing us it would have a bright white belly and often the mouth is agape. Scuplin often start producing slime that drips from the body if they are carried very long before consumption.
In this photo the anchovy is obviously a little larger than 2 bill length which would make the fish in the 12-14 cm size class. This anchovy also has a deepbody anchovy giss to it, but I am not certain without a better side profile that relates the anal fin and dorsal fin bases to each other (See Miller & Lea Fish Bulletin 157). The photograph was taken in Morro Bay which is in the northern range for the deepbody. Note how this picture shows little or no blood in contrast to the earlier photo. The big eyes, round nose, and small thin lower jaw leave no doubt that this an anchovy. The general flexibility here is also very typical.
This is a great shot of an anchovy, perhaps even a deepbody anchovy (Anchoa compressa) based on the relatively short distance between the back of the eye and the ventral edge of the operculum. Also the hues seem a bit more brownish green than the bluish black that is typical in the northern anchovy. The fact that the fish is bleeding and shows head wound trauma is very typical of anchovy in general. Elegant Tern bills range from 56 - 70 mm, but using a mean of around 63 mm would result in an estimated fish length of just over a bill and half or 10 cm.
This Caspian Tern has caught or repositioned this Clupeid and if you review the related Flickr photo set by jsutton8 you can see the tern evading some kleptopiratic Western Gulls. This fish is at least two bill length (7 cm) or approximately 15 cm. It has the small clear heavily forked and acuminate (pointy) tips to the tail and a sharp keel to the belly. Not the clear keel sharpness near the slightly flared operculum. An anchovy would be more rounded in the belly. The size and roundness of the operculum is chararcteristic of both herring and sardine in the SF Bay area and without a clear view of the mouth, head from the top and eyes it is impossible to tell.
This breeding Rhinoceros Auklet is carrying a pair of Sand Lance which are relatively easy to identify because of their very skinny fusiform shape and the strong contrast between the dark back and bright silver belly. The tail fin appears to be under water but the caudal penduncle tapers symmetrically and very quickly which helps distinguish these fish from any other eel or lamprey. Sand Lance are very flexible and hang down from the bills regardless of the predator. If the exposed culmen is estimated at 32 mm then the fish must be 15 cm or 5 bill lengths.
In this photo a Caspian Tern with a salmonid it is harder to identify the field marks that make this fish a salmon. Look for the dark color to the rounded tail tips. The tail is only forked a little and as is typical of salmonid smolt of this size not inclined to collapse down. The white belly with no transluscence, long fusiform body and full head also help ID this as a salmon. This fish is between 21 - 24 cm using an estimated exposed culmen of 7 cm on the tern. Another characteristic of this fish that fits a salmonid ID is the point where the head is flexing up. Salmonids are relatively flexible for a fusiform fish of this size (i.e. a herring of comparable size would be stiffer and straight).
This photo of an adult Caspian Tern and its salmon prey is about as good as it gets. If we assume the terns exposed culmen (top of the bill) is 7 cm then the fish must be at least 21 cm or 3 bill lengths. I would estimate the fish at closer to 24 cm given bend in the body. Salmon species are challenging to identify unless you have them in hand, but this fish is almost certainly a steelhead. The smokey dark tips to the tail are not diagnostic alone, but they are very often conspicuous in salmon smolt, especially steelhead.
