Los Angeles Audubon Society

WesterNTANAGER

Volume 71 Number 5 May/June 2005

Pelagic Birding in the Southern California Bight: Part I

by Todd McGrath and Jon Feenstra

By taking a spotting scope to acoastal bluff during the properseason we can glimpse the

remarkable world of pelagic birds. AJanuary morning might reveal hundredsor even thousands of Black-ventedShearwaters movingalong the coast,while in April, itmight be SootyShearwaters, or afew jaegers movingnorth. A variety ofnearshore pelagicscan be seen duringthese “seawatches”,and many activebirders regularlyspend parts oftheir birding dayslooking offshore. Asfascinating as theseseawatches can be,to truly experience therichness of southernCalifornia’s pelagic life, it is necessaryto venture offshore by boat, which is thesubject of this article. In Part I we willdescribe how the ocean topography in theSouthern California Bight combines withwind, current, and water temperatures toproduce the conditions required forpelagic birds to flourish. We will alsodescribe the pelagic birding opportunitiesavailable in our region. In Part II, we

will provide a list of the pelagic birdspecies recorded off southern Californiaas well as notes on their status and distri-bution in our region.

For purposes of this article, we aredefining a pelagic bird as any species

that spends the vastmajority of its time insouthern Californiaout at sea or on off-shore islands, and themajority of its non-breeding time at sea.

Southern Califor-nia is well representedin this regard as thefollowing groups havebeen recorded in ourwaters (the parenthet-icals indicate thenumber of speciesrecorded from eachgroup): albatrosses (3),fulmars (1), petrels (6),shearwaters (9), storm-

petrels (7), boobies (3), tropicbirds (3),phalaropes (1), jaegers (3), skuas (1),kittiwakes (1), gulls (1), terns (1), andalcids (12). That totals to a remarkable 52species, and while a number of those areaccidental vagrants, it is still a remark-able total. Note that only the pelagicmembers of each group are countedhere. Sea ducks, loons, Brandt’sComorant, Brown Pelican, Red-necked

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Phalarope, gulls, and terns are also oftenseen on pelagic trips but are not dis-cussed in detail here, due to the fact thatthese species may also be commonlyseen onshore. Our discussion is furtherlimited to the area south of Pt. Concep-tion and north of Baja, Mexico, as it isthe area most frequently visited byorganized pelagic trips.

Anyone who has been on a pelagictrip knows that birds are not evenly dis-tributed over the ocean. Some areas holdlarge numbers of birds, while other areasare almost completely barren. As wouldbe expected, this is most often due to thepresence or absence of food. On land,birders regularly predict the species theywill encounter in a particular location bylooking at the habitat. Areas that canprovide food, cover, and water are likelyto hold good numbers of birds. Theocean has habitats as well, but as landdwellers, we are ill-equipped to differen-tiate between the various ocean environ-ments using only our senses. Instead wemust use charts and satellite imagery to

look for the features that may indicatethe presence of pelagic birds. We say“may” deliberately. In spite of what wehave learned, it is still difficult to predictor understand why areas will have largenumbers of birds one day, and be rela-tively barren the next.

The oceanic neighborhood off LosAngeles is part of a greater geographicarea known as the Southern CaliforniaBight (the Bight). It is bordered by landto the north and east, by the CaliforniaCurrent to the west, and it extends southroughly to Cabo Colnett between Ense-nada and San Quintin, Baja California. Itcan be thought of as a pocket of slack-water on the edge of a stream. In thiscase the stream is the California Currentwhich flows south along the coastline ofnorthern and central California and con-sists of cold, nutrient-rich water. It contin-ues flowing south as the coastline curveseast at Point Conception. At the southend of the Bight, the current forks andsome (the Southern California Counter-current) returns north up the coast creating

a counterclockwise eddy (see Figure 1).The relative influences of the current andcountercurrent vary according to season.In the late winter and spring, with thehelp of northwest winds, the Bight isdominated by the cooling effects of theCalifornia Current. In the late summerand back into winter the region succumbsto the warmer, less biologically produc-tive current from the south. In addition,water properties are strongly affected bywind and such climate conditions as theunusually warm waters associated withthe El Niño Southern Oscillation(ENSO), and the related cooler waters ofLa Niña. ENSO events occur every 2-7years, and vary greatly in intensity andduration. Most last 6 to 18 months andaffect the tropics strongest, with smaller,less predictable effects in the NorthPacific. The strongest ENSO events canhave a devastating impact on breedingseabirds in the tropics and the NorthPacific causing some species to dispersefrom their normal ranges in search ofcooler nutrient-rich waters. During the

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Figure 1: Yearly averaged ocean currents of the Southern California Bight. (Hickey, B.M. 1997.)

rather strong 1997-1998 ENSO, vagrantspecies like Great-winged Petrel, Bulwer’sPetrel, and Wedge-tailed Shearwaterwere all recorded in Monterey Bay toour north, but it is unclear whether thoseoccurrences were directly related to theENSO event. Perhaps more interesting isthe discovery of a longer term trend ofwarming and cooling waters in the NorthPacific (with some impacts in the tropics)called the Pacific Decadal Oscillation(PDO). This phenomenon is similar to anENSO event, but the trends last 20-30years. Some scientists believe the strong1997-1998 ENSO event was the end ofa warm cycle PDO that started in 1977(Bond and Harrison, 2000). If thatassertion proves true, a cooling of theCalifornia Current should result in excel-lent conditions for observing pelagicbirds off southern California in thecoming years.

As discussed above, while watertemperatures vary from year to year, thecombination of cool nutrient-rich waterfrom the north and warm water from the

south in part explains the diversity ofpelagic species recorded in southernCalifornia, as warm water species such asBlack and Least storm-petrels reach thenorthern end of their normal range a fewhundred miles up the coast, and Red-billed Tropicbirds are rarely recorded tothe north of our region. The southernlimit of breeding for Cassin’s Auklets (acold water species) occurs a few hundredmiles south of our region on GuadalupeIsland, off Baja (Jehl and Everett 1953),providing an example of how both coldand warm water species can thrive in themixed waters off southern California.The Channel Islands also play a role inthe diversity of pelagic bird life, as theyare important nesting areas for pelagicbirds, most notably for Ashy Storm-petrel (except for a few pairs that maybreed on Los Coronados, an endemicCalifornia breeder) and Xantus’s Mur-relet. More information on the breedingpelagic birds of the Channel Islands willbe included in the species accounts inPart II of this article.

The most significant biologicalproductivity and often the highest birdnumbers occur in locations where coldnutrient-rich water is pushed to the surface.Surface-bound nutrients support phyto-plankton, which makes up the base of theentire marine food chain. The planktonfeed the anchovies, squid, and krill thateventually end up in the bellies ofseabirds and marine mammals. Hence, tofind the birds, we have to find their food.The complicated undersea landscape(see Figure 2) of the Southern CaliforniaBight makes points of nutrient upwellingwidespread. The Channel Islands andthe assorted ridges, basins, mounts,banks, and canyons that pepper the areaact as ramps for the submarine currents.Much in the same way that newspapersand grocery bags are blown skyward bywind banking off buildings in downtownLos Angeles, nutrients are brought upby the deflection of currents from theseobstacles. Upwelling can also occur at theinterface between different types of water.Sharp changes in surface temperature,

May/June 2005 3

Figure 2: Submarine topography of the Southern California Bight. (adapted from Briggs, K.T., et al. 1981)

salinity, or current direction will cause achurning effect as the water massesequilibrate. Nutrients are often trapped inthe region between. Sharp changes inwater surface temperature can be locatedusing satellite imagery. This approach isparticularly applicable in the deepwaterareas along the continental shelf whereupwelling due to ocean floor topographyplays a smaller role. However, these sharptemperature breaks are only present whenthe wind and currents create them, andthey can disappear quickly, adding frequentfrustration to birding by this method.

Points of greatest nutrient upwellingcaused by permanent aquatic features arethe destinations for most pelagic birdingtrips. For instance, flip to the PelagicTrips page in the back of the Tanagerand read the descriptions for a few of thetrips. Now, take a look at Figures 1 and 2and locate the places mentioned. Featuresshowing steep slopes and a large changein elevation are natural places to find anupwelling of nutrients. Notice how thecurrent flows west directly across thedeep-water (1000+ fathoms) of the SantaCruz Basin and hits the Santa Rosa-Cortez Ridge just south of Santa RosaIsland (the Santa Rosa Flats). Theseareas are prime targets on fall pelagictrips when the flux of the CaliforniaCountercurrent is at its height. Furtherout, the Condor Express trips leavingSanta Barbara often focus on thefeatures west of San Miguel Island (e.g.Rodriguez Dome and Arguello Canyon).These areas are the sites where upwellingof the cold California Current occurs –

just on the edge of theSouthern California Bight,and along the deepwater ofthe continental shelf.

Still further out, themulti-day trips from SanDiego on the Searcher lookat the edge of the continentalshelf and well beyond. Oneof the advantages of thesetrips is that one can spenddays in the deep waterswhere Pterodroma petrelsand albatrosses are mostlikely to be found. Thedensity of these species insouthern California can be

quite low, so spending days rather thanhours in the proper habitat greatlyincreases your odds of seeing these birds.

Whether you venture just a fewmiles offshore, or go out hundreds ofmiles off the southern California coast,you will see some of the remarkablebirds that call the Pacific Oceanhome. Organized pelagic bird-ing trips regularly encounterother interesting marine lifesuch as seals, dolphins andwhales. Often many forms ofmarine life including pelagicbirds will all be exploiting thesame food supply. The sight ofa large herd of dolphins withhundreds or thousands of pelagicbirds circling is simply awesome.Below is a list of pelagic touroperators in southern California.We hope to see you on one ofthese trips soon.

Pelagic Birding Opportunities inSouthern California:

As a disclaimer, Jon Feenstra is afrequent leader on Los Angeles AudubonPelagic trips, and Todd McGrath has ledtrips for all the operators listed here.

Los Angeles Audubon Societywww.laaudubon.orgLos Angeles Audubon offers a

schedule of about six pelagic trips a year.For exact dates visit the website listedabove or check the Pelagic Trips sectionof the Western Tanager. The annualTropicbird trip at the beginning of Sep-tember is quite popular and books uprather quickly. Many of the other trips visitthe ledges and canyons surrounding thenorthern Channel Islands. The spring tripto Santa Cruz Island to see the IslandScrub Jay also usually encounters numbersof pelagic species including Xantus’sMurrelet. All trips are staffed with expe-rienced volunteer leaders that know thebirds and marine life.

Searcher Natural History Tripswww.bajawhale.com/birdingtrips.htmlThe Searcher offers four day trips

from San Diego that venture out to areaspast the continental shelf. There are gen-erally at least two trips a year, one inApril and another in early September.These trips generally proceed up to thenorthern Channel Islands and then southalong the edge of the continental shelf.These trips are the best chance to seePeterodroma petrels such as Murphy’s,as many were seen on both spring trips in2003. See the species accounts in Part II

South Polar Skua

Black-vented Shearwater

Cassin’s Auklet

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for a discussion of other Pterodromaspecies. Laysan and Black-footed alab-trosses are also regular on the spring trips.The fall trip has produced such raritiesas Bulwer’s Petrel and Red-tailedTropicbird. A fine variety of marinemammals has also been recorded onthese trips. The captain and crew of theSearcher provide an outstanding level of

service, and the trip price includes allmeals and beverages. With advance noticethe Searcher crew can accommodate anyspecial dietary requirements.

Condor Expresswww.condorcruises.comBased in Santa Barbara, the Condor

Express is one of the premiere boats insouthern California. This fast, stableCatamaran can get out to the deepwaterquickly, maximizing the birding time inthe productive offshore areas. The largeenclosed cabin and full galley withexcellent food are also plusses. Theexcellent, friendly crew is always joinedby a group of experienced pelagic leaders.The LA Audubon Society has used thisboat for the past two years to conduct itsvery popular “tropicbird trip.” Murphy’s,Cook’s, and Dark-Rumped(Hawaiian/Galapagos) petrels have allbeen recorded on deepwater trips aboardthis boat.

Flesh-footed Shearwater

May/June 2005 5

Bird Tape(323) 874-1318

Jon Fisher records the Bird Tape.Please report interesting bird sightingsto him at:

Jon Fisher(818) 544-5009 (work)JonF60@hotmail.com

References:Bond, N.A. and D.E. Harrison, D.E.

2000. The Pacific Decadal Oscillation,air-sea interaction and central northPacific winter atmospheric regimes.Geophys. Res. Lett., 27(5), 731-734.

Briggs, K.T., Lewis, D.B., Tyler,W.B., and Hunt Jr., G.L. 1981. BrownPelicans in southern California: habitatuse and environmental fluctuations. TheCondor 83: 1.

Hickey, B.M. 1992. Circulationover the Santa Monica-San Pedro Basinand Shelf. Prog. Oceanog. 30: 37.

Jehl, J.R. and Everett W.T. 1985.History and status of the avifauna of IslaGuadalupe, Mexico. Transactions of theSan Diego Society for Natural History20: 313-336.

Jones, J.H. 1971. General Circula-tion and Water Characteristics in theSouthern California Bight. SouthernCalifornia Coastal Water Research Pro-ject TR101.

Lehman, P.E. 1994. The Birds ofSanta Barbara County. UCSB VertebrateMuseum. Santa Barbara.

Russell, R.W. and Lehman P.E.1994. Spring migration of Pacific Loonsthrough southern California: nearshoreflights, seasonal timing and distributionat sea. The Condor 96: 300.

Sibley, D.A. 2001. The SibleyGuide to Bird Life and Behavior. AlfredA. Knopf. New York.

Part II of this article appearing inthe next issue of the Western Tanagerwill contain accounts of the status anddistribution of pelagic species in south-ern California, including breedingpelagic birds of the Channel Islands.

The Authors:Jon Feenstra is a native of AppalachianNew Jersey and a lifelong outdoorsenthusiast. He moved to Pasadena in2000 where he is currently a graduatestudent in physical chemistry at theCalifornia Institute of Technology. Inaddition to working on his PhD andoccasionally birding, Jon also leadsfield trips for the Pasadena and LosAngeles Audubon Societies and writesthe Birds of the Season article for theWestern Tanager.

Todd McGrath has more than 250 daysat sea studying pelagic avifauna. Hehas over 100 days at sea on each coastof the United States. Todd has visitedAustralia, South Africa, and Antarcticato view seabirds. He also serves on theBoard of Directors of Audubon Califor-nia, and is a frequent leader of LAASpelagic trips. A resident of Californiasince 1997, he lives in Marina del Reywith his wife Pamela and their twodaughters Katelyn and Sarah.