A Productive Pelagic

 

Whenever there is an El Nino, there is a lot of anticipation of rare pelagic species owing to the changes in water temperatures and potential displacement of species far from their normal abodes. In practice, there are a number of species – Least and Black Storm-petrels, Craveri’s Murrelets and Elegant Terns, for example – that do predictably move further north, but we are still waiting for Wedge-tailed Shearwaters to show up more commonly even though they are quite regular in numbers around the southern tip of Baja California.

One group of birds that has become much commoner over the last decade is boobies. I was hopeful that the “Super El Nino” would bring in an influx of Masked, Nazca and Red-footed Boobies into Southern California mirroring the effect of the “Blob” a few years ago.

Although sea surface temperatures were much warmer than normal in the spring, after that they failed to advance much through the early part of the summer and it was only in August that they started to again rise above normal. This triggered an influx of Masked and Nazca Boobies. I had to miss a couple of pelagics in August as my daughter’s wedding understandably took higher priority. Needless to say, no less than four species I have yet to see in Santa Barbara County were seen on those trips!

We had two pelagics planned in mid-September, the first to the Santa Barbara Island (SBI) booby colony and the second a 12-hour trip that aimed to get to the waters towards the southwest of the county. However, as the dates approached, the weather forecast was horrible. Although it improved a little at the last moment, it was too risky for me to go on the 12-hour trip as I often get badly seasick on them.

Least Storm-Petrel

The SBI booby trip tends to go on a less inherently windy route and it was with considerable anticipation that I boarded the Island Explorer on Saturday morning. Our route initially crosses the Santa Barbara Channel to Scorpion Anchorage where we drop off day trippers to Santa Cruz Island. After that the official pelagic begins. Usually, I don’t do much birding on the channel crossing as it is rather dead for birds. That day, however, was different with some Common Terns, large numbers of Red-necked and lesser numbers of Red Phalaropes in the channel, along with numerous Least and Black Storm-petrels showing well. Least Storm-petrel occurs most years off Southern California but are more numerous in warm water years. They are almost unknown in the channel.

Ashy Storm-Petrel

Once we headed south through the Anacapa passage and out along the edge of the deepwater Santa Cruz Basin, we continued to encounter a steady stream of storm-petrels as well Black-vented and Pink-footed Shearwaters and a few Craveri’s Murrelets and Cassin’s Auklets. Eventually we added Ashy Storm-petrel and I then saw small storm-petrel with conspicuous white rump, suggesting a Wilson’s or perhaps a Townsend’s. We were able to follow it in the boat and get good looks, quickly determining it was a Wilson’s by its flight style, wrap-around white rump, the lack of a fork in its tail, the wing shape and the feet projecting beyond the tail in flight. My exultation at a new Santa Barbara County bird was cut short as we realized we were actually in Ventura County waters. Fortunately, we were extremely close to the “county line” and the bird was heading west towards it. It obligingly kept going until we reached Santa Barbara waters.

Wilson's Storm-petrel

As we headed out into even deeper waters, we started to encounter Leach’s Storm Petrels, including some of the dark-rumped Chapman’s form. At one point, I had a “Leach’s type” that looked a bit smaller with more white on the rump, but the views were far from sufficient to claim a Townsend’s.

Other than the storm-petrels, the outbound route was fairly quiet with a couple of poorly seen jaegers, an Arctic Tern and a juvenile Sabine’s gull. As we got close to SBI, we began to see a few Cocos (formerly Brown) Boobies and upon arrival at the colony, we immediately noticed a subadult Nazca Booby sitting on a rock among some cormorants. This bird has an extensively pinkish-toned bill, making identification straightforward.

Nazca Booby

A systematic scan of the cliff face soon located a Blue-footed Booby among all the Cocos – a lifer for many of the participants. We were unable to find any other rare boobies in the colony and after checking a couple of nearby rafts of Black-vented Shearwaters, we began to head back.

Our route back was a to the east of our outbound route as we wanted to check the Pilgrim Bank, which sometimes has concentrations of seabirds, and Anacapa Island, where there had been recent reports of roosting boobies. An added bonus was that it was slightly more offset from the NW swell.

Red-footed Booby

After seeing more of the same on the return journey, we arrived at the east end of Anacapa and were immediately greeted by not one, but two Red-footed Boobies that flew close by the boat and sat on the water for excellent views. I have now seen three in Ventura but none in Santa Barbara! Motoring closer to the cliffs, we found 9 Cocos Boobies and another sub-adult Nazca. The latter had more yellow on the bill than the one on SBI but after positioning for some better lighting, it was apparent there was a fair amount of pinkish in the bill. As we made the crossing back towards Santa Cruz Island, we found yet another Masked or Nazca Booby. This individual was a younger bird, probably molting out of juvenile plumage. We may be able to determine the identification after a study of the best photos taken.

Immature Masked or Nazca Booby

A four-booby day is pretty impressive, although it’s becoming somewhat routine in warm waters years on these trips.

Thanks to Sophie Cameron for the photos in this post.