This is the trip report for the Buena Vista Audubon and Grande Sportfishing Pelagic trip Sunday June 10, 2018. Thirty-nine passengers and five leaders meet in front of H & M Landing for the 7 a.m. departure out of San Diego Bay. Skies were mostly overcast with some sun breaking through, and a south breeze at 5 kts. I did a brief orientation to the expected sea conditions, safety, the boat lay out, and the task of birding at sea. We headed down the dock to the Grande where we met up with leaders Todd McGrath, Bruce Rideout, Matthew Binns and Gary Nunn. Once settled in, we departed for our adventure at sea.
The trip down the bay had the expected Western Gulls, Caspian, Royal, and Elegant Terns, and Brandt’s and Double-crested Cormorants, and even a couple of Barn Swallows. Cruising by the bait docks we could see the usually suspects – herons, egrets, pelicans, and the like gathered to steal a wayward baitfish or two. We also picked up two adult breeding-plumaged Heermann’s Gulls following the boat looking for a handout. This Mexican breeding gull has created some concern for the last few years, as adult Heermann’s Gull were arriving back here from their breeding islands in the Sea of Cortez much too early and lacking any juveniles. Seems the sardine populations in the gulf had crashed, or at least were not available to the breeding gulls. Our June trip in 2016 had over 60 Heermann’s Gulls. Last year that trend seemed to be turning around as adult gulls (13 on the 6-11-17 trip) arrived here at the more normal post-breeding dates and juveniles appeared in small numbers. Today these two Heermann’s Gulls and one more offshore would be the more characteristic few expected failed breeders of a “normal’ year. We cruised down the buoy line hoping for a loafing booby but found none. Boy would that change before long!
Offshore we had a flyby Black Oystercatcher. A nice bird for San Diego, where this species reaches close to the southern limits of its range. Black Oystercatchers are rare but somewhat regular in very small numbers along our rocky coast. They are more commonly seen at the Coronado Islands in Baja California, Mexico, just 12 to 15 miles to our south. They are sometimes seen transiting over open ocean to and from those islands. The area south of Point Loma was very active, so we chased the mass of feeding Elegant Terns down to the southeast. Elegant Terns are also a Mexican breeding species. Prior to the 1960s, the only known breeding was on a couple of small islands in the Sea of Cortez. One, La Raza, is the same breeding island where most of the Heermann’s Gulls nest. Recent history has seen a breeding colony established in the Salt Works in the south end of San Diego Bay. That site has grown into a major breeding location for the species, sometimes with birds numbering in the tens of thousands. Today many of these Elegant Terns were taking advantage of so much forage fish so close to home.
This area also held a surprising number of Black-vented Shearwaters. This is our local inshore shearwater and also a Mexican breeder, although on islands from the Pacific side of the Baja peninsula. Most breed on just one island, Natividad. Spring is also their breeding season, so normally we would not expect this many in local waters. There was certainly plenty of food here and that may have been holding them up here if food is scarce closer to their breeding islands. We did see Common Dolphin here but they were fast moving and clearly intent on chasing down breakfast. We never caught up to them.
Then the scream went out “booby on the water”. Not 50 yards away was a near adult Nazca Booby on the water. Prior to last year this would have been a mega rarity. Then 2017 turn out to be the Nazca Booby year with more than a dozen west coast sightings. Several even seemed to be trapped in San Diego Bay and were seen by hundreds of birders. Two stayed into this year and were seen by a boatload of birders at the SDAS Bird Festival in February. All of those photographed in San Diego Bay were adults. This bird, although outwardly appearing a full adult while on the water, showed a small amount of remaining dark subadult feathers in the otherwise white lesser coverts. Photographs in-flight also showed a metal band on the right leg. From the photos we could even make out a few letters and numbers. The band was of some concern because a Nazca Booby was rescued off Oregon, flown to San Diego, rehabbed, banded, and released here, which would have made it uncountable. However, Gary Nunn was able to trace the partial band information to a bird banded as an immature on Isla Espanola, Galapagos Islands, in the first half of 2017. This would make the bird about 1 3/4 years old at time of sighting here in San Diego. BTW this bird was about 6.5 nautical miles south of Point Loma, but only about 5.5 n.miles off Imperial Beach.
Nazca Booby was only recently separated from the very similar Masked Booby (which I mistakenly called this bird at first sighting), but the bright orange bill was unmistakable. Nazca are from the northwest coast of South America and famously from the Galapagos Islands. Nazca Boobies may have recently switched to flying fish as a replacement food source for the declining sardines they normally feed on, so this may have set these birds off and out of the normal range. Boobies in general seem to be ship followers and often ride on boats for long distances, which would provide the double benefit of the boat ride and the flying fish kicked up by the boat out in front of them. Whether this bird got a ride or made it here on its own is anybody’s guess. Great bird no matter what.
We turned back north and west to avoid crossing into Mexico and continued toward the Nine Mile Bank. Over the deep water inside the bank we had a mammalian rarity – a Guadalupe Fur Seal. They breed on some of the same Islands as the Black-vented Shearwaters off the west coast of Baja California. They were thought to be extinct at one time, as the sea otter hunters nearly wiped them out. They spend the majority of their lives, and are seen regularly, out in the cold California Current. This fur seal did the typical jug handle pose, lying on its back with fore flippers curving back to meet the raised tail flippers. This is thought to be a thermoregulating mechanism after a deep dive into colder water.
The inner Nine Mile Bank also turned up a pair of Scripps’s Murrelets. These are regular local breeders on the Coronado Islands. The question this year has been why we were seeing so many on the May 20th trip, but none with chicks. Today’s numbers seemed a bit low, though by June, many if not most Scripps’s Murrelets are done breeding and have moved off to sea to our northwest. This could be an indication of a late start to the breeding season. The outer edge of the Nine Mile Bank had good numbers of Sooty Shearwaters, Elegant terns, and more Common Dolphins. We started picking up a few Pink-footed Shearwaters and Black Storm-Petrels – all expected here. Sooties and Pink-foots are Southern Hemisphere breeders. Sooty Shearwaters are mostly from New Zealand and move across the whole Pacific Ocean to feed and molt in the rich waters of our west coast. Pink-footed Shearwaters breed off Chile and do the trip north to these food rich waters. Black Storm-Petrels, on the other hand, are local breeders off the west coast of Mexico and extreme Southern California and are our most abundant storm-petrel. We got some looks at a Fin Whale in this area but our chase proved fruitless. Fin Whales are exceedingly fast and prone to switch directions if they do not wish to be viewed. So that was the case today.
The deep water outside the Nine Mile Bank is known as the San Diego Trough. Mostly featureless, it can be rather boring. Once in a while it does turn up a good bird and it did so on our way out today. A call came from midship of an approaching Booby. This bird came right at us from our 8 o’clock position and flew right over the boat – a subadult Masked Booby! Everyone got great looks as it passed by the boat. This bird still had a bit of the 5 o’clock shadow on the head and upper neck, with a nice broad white collar. The upper wing still was mostly dark as was the tail. The bill color on this near adult bird was that off yellow-green color they often have. Two species of Boobies for the day and neither was a Brown Booby. Very nice and very unexpected. We did expect to see Brown Booby for the day, but were wrong on that count. Nazca and Masked Boobies were it for the day. The Masked Booby was about 15 n. miles west of Point Loma.
The Thirty Mile Bank was a bit of a disappointment today. We did have a nice mix of storm-petrels though: the larger all dark Black Storm-Petrels with their deep wing stroke; the smaller paler Ashy Storm-Petrel with a more fluttery flight style; and the mostly dark Chapman’s subspecies of Leach’s Storm-Petrels with their erratic zig-zaggy flight. Most Leach’s here show little or no white on the rump and when they do it well divided in the middle. We did have a little excitement with a “mystery” shearwater. This bird was seen at a great distance after a long dry spell. The feel was something new and different. Unfortunately once back on dry land and the photo enlarged on a computer screen the mystery was over…Pink-footed Shearwater.
The trip back across the San Diego Trough gave us a brief but fairly close look at a Townsend’s Storm-Petrel among a small raft of Leach’s. This is a newly separated species from Leach’s Storm-Petrel. Townsend’s Storm-Petrel breed only at Guadalupe Island and a couple of associated rocks. They are small, very dark, somewhat stubbier winged, and with a blazing white rump patch that wraps around to the under tail. Townsend’s Storm-Petrel is a regular post-breeding visitor to the area west of San Clemente Island, and is a nice bird to get in San Diego waters (inside San Clemente Island).
The remainder of the trip to The Nine Mile Bank and down was uneventful, though we did get good numbers of Sooty Shearwaters, a few more Black-vented Shearwaters, Black Storm-Petrels, and moderately good looks at a Cassin’s Auklet, which is never a guarantee. We got a fairly decent look at a Northern Fulmar, regular most years but now completely out of season.
Birds seen in San Diego Bay:
Great Blue Heron
Birds seen offshore:
Short- beaked and Long-beaked Common Dolphin
Guadalupe Fur Seal
California Sea Lion
Mola mola (Ocean Sunfish)
San Diego Pelagics