This is the trip report for the Buena Vista Audubon and Grande pelagic, June 12, 2016. The trip departed from San Diego Bay with 16 passengers and 6 leaders under overcast skies and mild breezes. Leaders for this trip were Tom Blackman, Todd McGrath, Gary Nunn, Dave Povey, Bruce Rideout, and Matt Sadowski. Although the passenger load was much lighter than usual, Capt. James McDaniels made the decision to go as a pre-fishing season shake down for his recent boatyard work. Our thanks to him for his unwavering support of our pelagic birding trips offshore.
Our first stop was the San Diego Bay bait docks for the usual suspects: pelicans, cormorants, herons, egrets and gulls, along with the lazing California Sea Lions. Nice photo ops here as always. We drove by Ballast Point, named for the cobbles on its beach once used as ballast on the sailing ships using this port. The beach had a fair number of adult Heermann's Gulls loafing, an oddly late or perhaps unable to migrate Pacific Loon in the water, and a few Barn Swallows overhead. The line of channel buoys leading out of the harbor were empty. We had come to expect Brown Boobies to use them as resting spots over the last couple of years. This year things are clearly different, as we've had no boobies on these buoys for the last two trips and only one on a previous April scouting trip. In fact today we saw only a single Brown Booby,an immature out near the 30 Mile Bank. In comparison this trip last year had 23. Something has clearly changed, whether water temperature, food source, or other unknown factors, sightings of this species is down.
Once we cleared the "Whistle" Buoy we angled off to the southwest to intersect the 9 Mile Bank and the Mexican border. This segment of the trip was marked by a few Black-vented Shearwaters, Brown Pelicans, Brandt's Cormorants, Heermann's and Western Gulls, lots of Elegant Terns, and a small number of Least Terns. We also had a rather inshore Black Storm-Petrel and Cassin's Auklet (neither one close to the boat), and both species again further out. Black Storm-Petrels were present in good numbers, and were fairly well seen by all. Cassin's Auklets were rather sparse and non very cooperative today.
At the inner edge of the 9 Mile Bank we turned northwest and followed along that edge. We picked up our first of many Sooty Shearwaters, but the best sighting was pair of murrelets that seemed promising. Normally spring murrelets are Scripps's Murrelets. They breed on the local islands, and return here from their winter areas in February and March and depart to the northwest in June and July. These two murrelets were a bit different: stiff raised tails that were a bit pointed in the center, perhaps a little darker above, a little longer billed, and as photos showed, with darkish underwings and a shoulder mark on the sides of the breast (the last two characteristics seen best in photos of birds in flight). These were two Craveri's Murrelets, nice birds to get for Southern California. Craveri's Murrelets are a Baja breeder, and eruptive post-breeding disperser to the north. Uncommon here some years absent completely in others. Expected arrival here is usually late July and August, some years not until September. In 2014 we had two Craveri's Murrelets on this same trip (June 7th that year). Then last year we had 20 on the June 14th trip. Something had clearly changed. The most likely culprit is the warm water "blob" in the north Pacific and strong El Nino on the equator, both prominent then, now on a rapid decline. Mexico has also made a concerted effort to remove various non-native pest species on their breeding islands. That should bode well for the overall population of Craveri's Murrelets and other species of breeding seabirds there.
We did get on pair of Scripps's Murrelets not long afterward on the outer edge of the 9 Mile Bank. They are a bit larger, perhaps 10%. They sit just a bit higher in the water, which exposes a little more white, the bill is a little shorter, the white comes up to the gape of the bill (but under the eye), and most conspicuously, a bright white underwing lining in flight. Scripps's Murrelets are part of the old Xantus's Murrelet complex. The "Northern form "scrippsi is now Scripps's Murrelet and the "southern form" hypoleucusis now calledGuadalupe Murrelet. We do get Guadalupe Murrelets here, though I feel it's one of the hardest "regular" occurring species to find inside the Channel Islands. Guadalupe Murrelet is perhaps the easiest of these three Baja and Southern California murrelets to separate at sea, as the white wrapping up around the eye is fairly conspicuous. Any first time birder here would be prudent to study those murrelets before any pelagic trips in the Southern California Bight. Photographs are always a big assist in identifying these species. I have had one extended 5 day pelagic with all three species, but to do that on a single day trip would be exceptional.
The middle of the 9 Mile Bank had lots of life, and the outer edge even more. We got a nice marine mammal show there, with a breeching Humpback Whale – one of at least two or three – a distant Blue Whale, and loads of Common Dolphins. We saw large spots of baitfish on the Grande's fish meters; most marked by diving Sooty Shearwaters, Elegant Terns, Brown Pelicans and others. One bait ball on the meter extended for more than a hundred yards. Captain James commented that it was larger than any he'd ever seen. Bait was plentiful and smaller bait balls on the meter were seen throughout the day. West of the 9 Mile Bank we found some small Black Storm-Petrel rafts. Most of these had 25-50 birds, and one was maybe close to 200. We had seen a few scattered Black Storm-Petrels inshore, and we would havescattered stormies the rest of the afternoon. Several of these rafts had a few of the smaller Ashy Storm-Petrels. One raft may have had as many as six. Always a nice find off San Diego, as Ashy Storm-Petrel nears the southern limits of their breeding range here. Their numbers locally are small in proportion to the abundant Black Storm-Petrel, and they tend to be rather boat shy.
A Red-billed Tropicbird, one of the more charismatic pelagics, was next – found by Gary Nunn. This bird was on the water close in to the 30 Mile Bank, some 23 nautical miles west of Point Loma. I think I can safely say every photographer on the boat got their Red-billed Tropicbird shot here, but just to be sure, we did a short chase to get back on the bird a second time. Red-billed Tropicbird is another Mexican species. Their numbers here are always small, so we savor every one we find. The last two years were off years for Red-billed Tropicbird locally. I saw only three here in perhaps 40-45 days offshore – odd, as it was in the midst of a warm water cycle. Perhaps they travelled up beyond us into areas not covered by birders. At the other end of the scale, in 2013 I saw 10 for the season here, and a roaring 21 on the more distant offshore 5 day pelagic trip to the self edge to our west.
We continued north along the 30 Mile Bank, and except for the previously mentioned Brown Booby and a couple of Pink-footed Shearwaters,nothing new was added, and no additional storm-petrel rafts were found. We turned back to the eastand set course for thenorth end of the 9Mile Bank. The numbers of rafting Sooty Shearwaters increased and started to have a small mix of Black-vented, and Pink-footed Shearwaters. Then Todd McGrath called out a ManxShearwater in the middle of one of the rafts. Fortunately, most folks on the bow got on the bird before the raft scattered. We did chase but did not re-find the bird. Tom Blackman got some excellent photos to prove our sighting. Likely the best bird of the day, and out of the "known" season for San Diego, which seems to be winter– mostly March. This bird was seen about 14 nm west of Ocean Beach. Nice sighting!
Black-vented Shearwater was once thought to be a race or sub species of Manx Shearwater. Before the two species were split, a small but regular number of "white-vented" birds were seen, and as more pelagic trips visit offshore the sightings, though still rare, have become regular. Breeding is now suspected somewhere in the North Pacific Ocean of this otherwise Alantic Ocean shearwater. While we were all looking at the Manx Shearwater, a Minke Whale surfaced quite close in. Not always the easiest whale to get good views of, this one surfaced two boat lengths off our bow. We pretty much made a beeline back to San Diego Bay after that, with good numbers of Sooty Shearwaters along the way, and more Black-vented Shearwaters and Elegant Terns near the Point.
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