This is the trip report for Oct. 22, 2017. Thirty-nine passengers and six leaders meet at Point Loma Sportfishing Landing on a glorious morning on San Diego Bay.
Leaders were Tom Blackman, Paul Lehman, Guy McCaskie, Bruce Rideout, Justyn Stahl, and myself. After an orientation we shoved off for a ride down the bay to the ocean.
We got looks at a number of the bay’s regular birds, including all three species of large terns –Caspian, Royal, and Elegant. Two of these, Caspian and Elegant, are in their annual seasonal decline. Elegant Terns will be gone in the next week or so. We also picked up the more midsized Forster’s Tern. Heermann’s Gulls are in good numbers now, making up about half of the gulls behind the boat as we started to chum. Heermann’s Gulls are a Mexican-breeding gull that disperses north to the west coast of North America. All are now in winter plumage, with a surprisingly good mix of juvenile birds of the year. I say that because juvenile birds have been nearly absent for the last three years. Breeding failures occurred on the colonies in the Sea of Cortez during those years. Today’s first winter Heermann’s Gulls made up about 5-10 percent of the gulls at the mouth of the bay.
Before we got the two-mile buoy (#3) off Point Loma, we had a flyby Parasitic Jaeger. We did a slight detour to the #2 buoy in hopes of a booby, but it turned out to be another Brandt’s Cormorant – an abundant inshore species here. The first leg of the trip had a couple of groups of migrating Common Loons. These are the regular early south-bound loon. Pacific and Red-throated Loons come down later, and in that order. I find loon migration flight interesting, as they clearly fly together as a group, but have no formation. They seem to be scattered all over the sky from near the surface to a couple of hundred feet off the water and hundreds of yards front to back. Makes getting an accurate count difficult, and sometimes one group seems to straggle into the next. I wonder at the benefit of this form of flock movement. Two lazy high flying Great Egrets came by us headed due south, then, as they could no longer see land in that direction, reversed course and came back over us as they returned in the direction of terra firma.
This area turned up our first Black-vented Shearwaters, Red-necked Phalaropes, and Cassin’s Auklets. All these species are pretty common once off the immediate coast. Black-vented Shearwaters became our most abundant species on the day, and we got much better looks as they came in to check out the chummed gull flock. We did get reasonably close to a number of Red-necked Phalaropes, but decent looks at Cassin’s Auklets as usual eluded us. Cassin’s Auklets, although relatively common here, just don’t let the boat approach. So for any look, the bow is usually the place to be. We did get a very distant look at a Brown Booby in this segment of our trip, which was one of three seen on the day. One other was also distant and poorly seen by many, but fortunately we were able to drive right up to the last one as it sat on the water, then got up and flew down the left side of the boat. This one was an adult male brewsteri Brown Booby (noted by frosted white head). I sure most got good looks and photos. Interestingly, Brown Booby sightings here seem to have tapered off a bit. The colony at Middle Rock just across the border seems to no longer be growing. This year found only one pair tending young, and very few juveniles or subadults there. Brown Boobies no longer seem to be interested in the chummed gull flocks either. They may be boobies, but they have learned that a gull flock behind a fishing boat doesn’t mean food for them. The rare Brown Booby that approaches the boat is almost always a juvenile. It will be interesting to follow the Brown Booby’s story in the coming years.
Once we hit the waters over the Nine Mile Bank we moved north along the spine and actually seemed to lose the birds. We had a couple of good pods of Common Dolphin, a few of which gave us a nice show with their bow riding. The Nine-Mile Bank has not produced the life this year that it has in the past. Interestingly the deep water over the San Diego Trough has been better. I would usually announce that the Trough was a good place to catch some lunch or a quick nap. Not this year. We’ve had to stay on our toes. But today it fell back into the typical mode. We did get Pink-footed Shearwater there, a species not shy about approaching the gull flock behind the boat. Today’s low numbers reflect the fall pullout and return to the southern hemisphere for their Austral summer breeding islands off Chile. Two juvenile Sabine’s Gulls were nice to see. They are at the latter end of migration from the high arctic to the warm climes of the southern hemisphere. A distant jaeger was also seen out here, but too far off to chase. Likely a Pomarine, but the other species can’t be eliminated at this point in fall migration, as all three species were seen on a scouting trip the previous weekend. We did get a nice look at a full “tail spoons” Pomarine Jaeger on the return to the coast. The Thirty-Mile Bank was as fickle as can be today. The storm-petrels seemed to have completely moved out. Overall this has been a poor summer for storm-petrel numbers here. We never really did find a large “raft” of the magnitude of recent years. Black Storm-Petrels numbers were very low all summer. Ashy Storm-Petrels numbers seemed good, perhaps better than most years. I thought Leach’s Storm-Petrels numbers were a bit low this year. Although this area is marginal to their main area further offshore, Least Storm-Petrels seem to be mostly a no-show. I say all of this as it was disappointing that the only two storm-petrels we saw flushed well ahead of the boat, and remained so distant that they could only be identified as “non-Black” Storm-Petrels. I did not see the birds, but one experienced seabirder felt they were likely Ashies . We did get good looks at a Northern Fulmar, as we did on last weekend’s scouting trip. This bird was a pale brown morph. Last weekend’s bird was a white morph. The one offshore oddity was a land bird identified as a Pine Siskin by sight and call. Certainly an unusual “pelagic” species! I gather Pine Siskins are on the move on land, so I guess we shouldn’t have been too surprised, but that’s a new land bird for me at sea. We picked up two interesting gulls on the way back towards the beach. Neither are rare, but both were early arrivals from the north. The first was a juvenile Bonaparte’s Gull, the other a first winter Glaucous-winged Gull. Bonaparte’s Gulls will become abundant locally this winter, with many thousands of birds some winters. Glaucous-winged Gulls are never in numbers here, but I would be surprised if we didn’t get one to three or four on a winter trip offshore here. We also had a good look at a young Elephant Seal on the way back in.
Species list for San Diego Bay:
Great Blue Heron
Black -crowned Night-Heron
California Sea Lion
California Sea Lion
Mola mola (Ocean Sunfish)