23 August 2015

23 August 2015

Hello fellow Seabirders,

This is the trip report for Aug. 23, 2015. This was a new trip added to the 2015 Buena Vista Audubon pelagic schedule, and was out of Mission Bay. The boat was the seventy foot Sportfishing Eclipse, owned and captained by Mark Gillette.

Using a new operation for pelagic birding is always a bit of an adventure, but Mark and his operation have run daily whale watching trips aboard the Privateer out of the same landing, under the Pacific Nature Tours moniker. Quite a number of birders have started using that operation as an easy way to get offshore when organized birding trips are not available. The frustration here, as with whale watching trips everywhere, is that the primary goal is whales! They often pass flocks of feeding birds tantalizingly close on their way to the nearest marine mammal. Talking to Mark, he was starting to get the sense that pelagic birding was an opportunity being missed, and that whale watching, as with fishing, uses many of the same elements to be successful. Our thanks to him for giving us an opportunity at a time of year when the fishing boats have just not been available locally.

Forty eager birders and six leaders met at Seaforth landing. We boarded at 7:10, did a brief orientation, then departed at 7:30 sharp. Leaders where Peter Ginsburg, Guy McCaskie, Gary Nunn, B J Stacey, Justyn Stahl, and myself. We were under overcast skies, unusual for August, but my preferred sky for seabird viewing. This was a ten-hour trip.

Seaforth Landing has the benefit of a short mile and a half ride out to the ocean, the bait dock with the usual Great Blue Herons, Great and Snowy Egrets, Western and Heermanns’ Gulls, Double-crested Cormorants, and Brown Pelicans is passed within the first couple of minutes into the trip. We had a few Caspian Terns overhead and an Osprey on a nearby sailboat mast. The trip along the rip rap jetty turned up a Wandering Tattler which flew off the south as we stopped to get on the bird.

Once in the ocean we headed out to the west to a couple of bottom features. The first is a scattered rocky bottom area southwest of La Jolla, and the next is a rather steep drop (150 fathoms) into deeper water – the areas known as the 270 Spot and the Six Mile Bank. This area has held a fair amount of life all summer., and so it did today as well. The swell was small (1-3 ft.), but as always interval is everything, and today it was a bit short at 6 seconds. Wind conditions were near zero (2 kts. or less early, perhaps 7 kts. in the afternoon), and visibility good at 8 miles or more. Sea Surface Temperatures (SST) remain warm at 72.4 – 74.6 degrees F. Temperatures were pretty uniform over the area we covered, with a very slight gradient – warmer inshore, cooler offshore.

Among the first birds seen here were two northbound Pacific Loons –our loon species most likely to be seen offshore, but oddly out of season. Pacific Loon southbound migration doesn’t start here until October and peaks more into November and early December. A fair number of Pacific Loons winter here, most leaving in the spring. These two likely spent the summer in the area off La Jolla and may just be doing a day light adjustment after drifting south all night.

Another species seen here was Brown Booby. They used to be an exceptional bird locally. No longer. We now expect to see Brown Booby on every trip and would be disappointed to miss them. So it’s appropriate that two Brown Boobies came in together this morning and a third showed up a short time later – all these being dark juvenile birds.

The arrival of Brown Boobies off Southern California likely occurred in the late 1990’s, and there was a steady increase in sightings as the colony on the Coronado Is. (Baja California, Mexico) grew into the early 2000’s. By 2010 we more or less looked for a Brown Booby on all our pelagic trips north of the border, but it was still hit and miss. Two or three seen on one trip then missed on the next two trips. Then the explosion seemed to occur in 2012-2013. They were being seen on sea watches from the beach regularly and in numbers. Offshore we’d count a day with one or two Brown Boobies as an off day. The San Diego Christmas Count for 2014 had 18 Brown Boobies (several were seen from the beach by Paul Lehman on the 2013 San Diego Christmas Count, and one was on the 1991 count, pers. ob.). On the 2015 San Diego Audubon Festival pelagic trips in March we would drive a considerable distance out of our way, to the buoys off the mouth of San Diego Bay, to view Brown Boobies from 15 ft. away.
Forgive my dissertation. I still find this change in this seabird’s range fascinating. Short story is today we had a paltry 25, including a few adult females.

This area west of Mission Bay had good numbers (hundreds) of Black-vented Shearwaters. Our local smallish dark above, whitish below, snappy wing beat, very short glide shearwater. Black-vented Shearwater arrived back here early this summer, giving some to speculate than most did not breed this year. Numbers of Black-vented Shearwater have remained strong here and just south of here off Ensenada, Mexico, so one would assume they are still finding food here. On a recent fishing trip near Black-vented Shearwater’s nesting islands there were still birds present there, and finding food, so some may still be breeding or at least hanging on there.

Black-vented Shearwater is an inshore species so once we left the Six Mile Bank we saw few until we returned to the north end of The Nine Mile Bank later in the day. About 1500 seen today. Certainly a good number for August.

Red-necked Phalarope, Common Tern, Cassin’s Auklet, and a very few Black Storm-Petrels were also scattered over the 270 Spot and just inside the Six Mile Bank, so we did a large circle over the area. Sharp-eyed Gary Nunn picked up on a distance Sabine’s Gull behind the boat, then a second, and a third, and by the time we got turned around the group numbered five, both adults and juveniles. One Sabine’s Gull came in right over the chummed gull flock. We doubled this count for Sabine’s Gull over the remainder of the trip.
A single Black Tern was seen in this area, which seemed to elude our attempt to chase it, though we did sight it again, or was that a second Black Tern? Regardless, we did have another Black Tern in the later afternoon inside the Nine Mile Bank.

Black Tern is actually seen somewhat regularly offshore as a summer migrant in small numbers. They start through here about mid July, peak in mid August, and trail off in September. Nice to get them, as they are uncommon here at best.

We had several jaegers here, not a surprise with small terns and gulls about. Several Pomarine Jaegers – some with large tail spoons, a few juveniles less well marked but barrel chested and with bi-colored bills – were hard to mistake. It was here that one of the many intrepid photographers took a photo of an apparently close in juvenile Parasitic Jaeger that no one else saw. So how did we leaders miss that one? As it turned out, that was the only Parasitic Jaeger on the day, with more than a dozen Pomarine Jaegers seen.

I had really hoped this area would produce murrelets, but none were seen. Clearly food items, such as plankton, small fish, and krill are there, as more than one Cassin’s Auklet was too full to fly. I was kind of surprised we didn’t score there, but sensing the natives getting restless, we pushed off to the west, searching for the elusive storm-petrel raft.

The San Diego Trough can be a rather quiet area and was so today. The “Trough” is a featureless deep-water area between the inshore bank, and the steep escarpment of the Thirty Mile Bank. This deep-water area can turn up some good stuff, but usually near one side or the other. That was the case today. As we approached the Thirty Mile Bank the number of storm-petrels increased dramatically. Unfortunately few came close enough to the boat for easy identification. Clearly the majority of the stormies were not Blacks. As we started to look at photos, many showed little smudges of white on the sides of the rump. A few birds even had a bold white rump patch. We were looking at Leach’s Storm-Petrels of the chapmani subspecies. This subspecies can have an all-dark rump or with varying degrees of white, from a slight edge to a nearly all white rump. Leach’s Storm-Petrel’s flight style is a little more manic than a Black’s, with few glides, frequent direction changes, and a bent wing look. They are also smaller overall than a Black Storm-Petrel. We had a lot of Leach’s Storm-Petrels today. They far out numbered any other storm-petrel species out in this area. We estimated close to 100 Leach’s Storm-Petrels in this zone, including a short tour into Los Angeles Co. (see the trip track).

Then just to add to the interest and confusion we saw and photographed two “Townsend’s” Leach’s Storm-Petrels. This diminutive race of Leach’s Storm-Petrel, known as subspecies socorroensis, is called Townsend’s to credit the man who first described this bird. “Townsend’s” Storm-Petrels breed only on rocks around Guadalupe Is. off Baja California. Recent thinking is that “Townsend’s maybe a separable species. Certainly they appear different from the nominate and Chapman’s subspecies in having a shorter rounded wing, short tailed look, and more of a hovering, gliding flight – almost Wilson’s Storm-Petrel like. Both of these “Townsend’s ” had a bold white rump patches, which seems to be the case for the majority of them. The white patch does not wrap under the tail. A few “Townsends” may show a dark rump, and fewer still the intermediate amount of white (per Steve Howell, 2012). We counted one “Townsend’s” for Los Angeles County and one for San Diego.

The last note on storm-petrels for the San Diego Trough is that initially we called a number of Ashy Storm-Petrels, but it appears most of those were wrong. We do have a couple photos of Ashy Storm-Petrels, so clearly a very few were present, but many fewer than originally reported – perhaps no more than 5 or 6.

The disappointment out in this zone was that we did not find the storm-petrel rafts we were hoping for. It seems to me that a few birds were gathering, but never more than a half dozen at a time. A longer search in this area may have turned up a raft, but time conspired against us, so we turned southeast toward the Nine Mile Bank.

All the further offshore areas had a pretty good numbers of Pink-footed Shearwaters. These guys always please the photographers. They make multiple passes and approach to within cell phone camera range. Large and dark above (many now a dark gray, with hint of a darker W pattern), with white bellies, a slower wing beat, and longer glides than the similarly marked Black-vented Shearwaters.
Sooty Shearwaters were scarce today, with only two seen – one near the Six Mile Bank, the other over the Nine Mile Bank. Lack of Sooties is not unusual for summer. We will see more of them again in the fall
The approach to the 178 area, near the north end of the Nine Mile Bank, gave us more action. The first was a nice pod of a hundred Common Dolphins. These guys put on a nice show. Next was a slightly spooky Fin Whale that gave us OK looks. We also watched a nearby sportfisher that had five or more Brown Boobies circling it.
The best sighting here was a young Black-footed Albatross sitting on the water, spotted by Justyn Stahl. The bird sat nicely as we circled. Black-footed Albatross is regular well offshore (100+ n.m.) this time of year, but rarely seen inshore in late summer and fall locally, so this was a nice addition to our day’s list.

We also had two White-winged Doves circle the boat here. The late summer and fall migration can be fun for land birds offshore as well. We got a little taste of that today. Besides the White-winged Dove, we also had two Mourning Doves near the Thirty Mile Bank, two Brown-headed Cowbirds, a Barn Swallow, and a hummingbird sp., all seen near the Six Mile Bank area. Throw in a small flock of Western Sandpipers that flew by in that same area. Migration is underway! The Nine Mile Bank had a nice mix of the birds seen earlier in the day. Coming in down wind and with the lighting behind us, gave nice looks at many more Black-vented Shearwaters, a few Black Storm-Petrels, a couple of Brown Boobies, Red-necked Phalaropes, another Pomarine Jaeger or two, Common Terns, and a few Elegant Terns. Just a note on Elegant Terns today: This is a species we normally see in such good numbers in the fall off San Diego that we may be guilty of under counting, or even ignoring, them to some extent. We counted something less than 30 for the day. I really noticed the lack of that species out here today. Why? Are they feeding in a different area? Have they started moving south? Have they dispersed off to the northwest? Perhaps other pelagic trips up the coast can give us an answer there.

My personal observation on a recent fishing trip from the west coast of the central Baja peninsula to all the way to Catalina Is. off Los Angeles was that the “concentration” was north of us. So perhaps Elegant Terns are dispersing to the north. How far north? Are other species that we associate with warm sea temperatures also there? Interesting questions. I think the coming fall pelagic trips will tell us more.

Scored as missing today off San Diego, Least Storm-Petrel, Red-billed Tropicbird, and Craveri’s Murrelet. The warm water is here, where are they?

My thanks to all involved today. Certainly was a pleasant day on the ocean with lots to see and something for everyone to learn.

Dave Povey

Pacific Loons 2
Black-footed Albatross 1
Pink-footed Shearwater 40
Sooty Shearwater 2
Black-vented Shearwater 1500
Leach’s Storm-Petrel 60
“Townsends” Leach’s Storm-Petrel 2
Ashy Storm-Petrel 6
Black Storm-Petrel 50
Brown Booby 25
Wandering Tattler 1
Red necked Phalarope 300
Pomarine Jaeger 15
Cassin’s Auklet 19
Sabine’s Gull 10
Black Tern 2 or 3 seen singly
Common Tern 20
Elegant Tern 25

Land birds made a good show today.
White -winged Dove 2
Mourning Dove 2
Hummingbird sp. 1
Barn Swallow 1
Brown-headed Cowbird 2

In the category of also seen;
Fin Whale 1
Common Dolphin 100+
California Sea Lion – many
Mako Shark 1
Smooth Hammerhead Shark 4
Striped Marlin 1

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