Northern Fulmar Fulmarus glacialis
The Northern Fulmar is primarily a winter visitor to the ocean off San Diego County. Its distribution varies greatly from year to year, the birds dispersing far offshore when the ocean is warmer, concentrating nearer the coast when the ocean is cold (Briggs et al. 1987). Under the latter conditions the fulmar can sometimes be seen from shore when the wind is from the west. On at least two occasions, perhaps because of a scarcity of prey, large numbers of fulmars have washed up dead on the county’s beaches.
Winter: As for other pelagic birds, La Jolla (P7) is the spot in San Diego County where the Northern Fulmar is best seen from shore. Counts there range up to 260 in 2 hours on 21 October 2003 (S. Walens). Counts on the ocean near shore range up to 205 on the San Diego Christmas bird count 21 December 1963. During die-offs, dead fulmars are found scattered on beaches the length of San Diego County. The most severe die-offs, affecting hundreds if not thousands of birds, were in March 1976 and the winter of 2003–04.
Migration: Briggs et al. (1987) reported the fulmar arriving in southern California in October, departing largely in March and April. Data specific to San Diego County reflect the same schedule. After incursions stragglers remain later, rarely clear through the summer, with individuals off San Diego 12 September 1982 (B. Barrett, AB 37:223, 1983) and 5 September 1987 (J. L. Dunn, AB 42:134, 1988).
Taxonomy: Fulmars of the North Pacific Ocean are F. g. rodgersii Cassin, 1862.
Cook's Petrel Pterodroma cookii
Petrels of the genus Pterodroma typically remain over deep water, off the continental shelf, at least near California. Only one has been reported closer to the coast of San Diego County than San Clemente Island.
Migration: One Cook’s Petrel was 16 miles west of La Jolla 13 June 1997 (M. Force, FN 51:1052, 1997). Other sightings of this species near the latitude of San Diego are at least 100 miles offshore.
Pink‑footed Shearwater Puffinus creatopus
The Pink-footed Shearwater nests on Chilean islands in the southeast Pacific and winters (in the northern summer) in the northeast Pacific. Though its numbers have declined, it is still fairly common off San Diego County. The Pink-footed has been affected less dramatically than the Sooty Shearwater by the decline in ocean productivity off California of the 1980s and 1990s.
Migration: Briggs et al. (1987) found the number of Pink-footed Shearwaters off southern California to increase sharply from March to May, then decrease sharply from September to November. In some years there are two peaks, in May and August or September. Though usually uncommon within 5 miles of shore, the Pink-footed Shearwater can be seen regularly from La Jolla (P7) in August and September if the wind is favorable (S. Walens).
Winter: From December to February the Pink-footed Shearwater is uncommon to rare. A count of three off San Diego 21 January 1984 was high for this season (G. McCaskie, AB 38:357, 1984). Probably because of winter storms driving the birds inshore, sightings from land are more frequent in winter than in summer. An example is one from Torrey Pines State Reserve (N7) 4 February 1999 (D. K. Adams).
Conservation: In the 1960s and 1970s the Pink-footed Shearwater was common to abundant off San Diego, with up to 6000 on 9 September 1972 (G. McCaskie). By the beginning of the 21st century the species could be rated only as fairly common. In its breeding range, consisting of only three islands, however, the Pink-footed also faces threats: introduced predators, degradation of habitat, and collecting of chicks for human food.
Flesh-footed Shearwater Puffinus carneipes
The Flesh-footed Shearwater ranges mainly through the Indian and western Pacific oceans and is rare off California, especially so toward the south. There are only 12 records for the waters off San Diego County.
Migration: As a migrant from the southern hemisphere, the Flesh-footed occurs off California mainly in the northern spring, summer, and fall. Dates for San Diego County extend from 9 April (1996, La Jolla, P7, S. Walens, NASFN 50:332, 1996) to 9 September (1972, two or three off San Diego, AB 27:119, 1973), except for one seen from La Jolla 13 February 2001 (B. L. Sullivan, NAB 55:227, 2001). The two sightings at La Jolla are the only ones from shore and the only ones for the county since 1981. Of note were two seen just south of the border near Los Coronados Islands 31 March 1996 (K. and C. Radamaker, NASFN 50:332, 1996).
Buller’s or New Zealand Shearwater Puffinus bulleri
Buller’s Shearwater nests on islands around New Zealand and migrates to the North Pacific, where it is sometimes abundant in fall along the coast of northern California. On the ocean off San Diego County, however, it is rare, with only about 16 records closer than San Clemente Island.
Migration: All but two of San Diego County’s records of Buller’s Shearwater range from 23 July (1981, eight 60 miles off San Diego, D. W. Povey) to 26 November (1994, one from shore at La Jolla, P7, S. Walens, G. L. Rogers, NASFN 49:100, 1995). The count of eight on 23 July 1981 is the maximum yet reported. Other than the one seen at La Jolla, the only fall record from shore is of one found dead along the Silver Strand (T9) 2 October 2002 (S. M. Wolf, SDNHM 50666).
Winter: Two winter records of Buller’s Shearwater for San Diego County lie outside the species’ usual seasonal pattern along the Pacific coast of North America. One was found dead on Black’s Beach (O7) 19 February 1976 (SDNHM 39756), and another was seen from shore at La Jolla 21 January 1995 (A. DeBolt, P. A. Ginsburg, NASFN 49:195, 1995).
Sooty Shearwater Puffinus griseus
Few changes in bird distribution have been as sudden and dramatic as the Sooty Shearwater’s desertion of the ocean off southern California. Before the 1980s, this visitor from the southern hemisphere was the most abundant seabird on the ocean off San Diego in summer. After El Niño hit in 1982–83 and the ocean remained at an elevated temperature for the next 20 years, the shearwater’s numbers dropped by 90% (Veit et al. 1996). A comparison confined to the ocean near San Diego County’s coast would likely show a decline even steeper.
Migration: The Sooty Shearwater begins arriving in April, peaks in May (Briggs et al. 1987), remains (or remained) common through September, and then decreases in number through December. In the 1960s and 1970s, on day-long boat trips out of San Diego, counts in the hundreds were routine. Estimates ran as high as 5000 on 9 September 1972 and 14 May 1977 (G. McCaskie) and 10,000 on 22 June 1970 (AFN 24:715, 1970). By the 1990s, typical daily counts were under 10. A feeding flock of about 200 off Point Loma (S7) 3 August 1998 was exceptional (P. A. Ginsburg). Sightings from shore, especially at La Jolla (P7), were more regular when the species was common. Guy McCaskie noted one following a fishing boat into San Diego Bay 5 May 1963. Sick or starving birds are picked up regularly on the county’s beaches.
Winter: From December to March the Sooty Shearwater is rare—currently much scarcer than the Short-tailed Shearwater. Before 1982, winter counts ranged up to 20 off San Diego 18 January 1969 (AFN 23:519, 1969). Since 1987, the highest winter count has been of three between San Diego and Los Coronados Islands 6 January 1995 (G. McCaskie).
Conservation: The decline of the Sooty Shearwater followed quickly on the heels of the decline in ocean productivity off southern California that began in the late 1970s: a decrease in zooplankton of 80% from 1951 to 1993 (Roemich and McGowan 1995, McGowan et al. 1998). The shearwater’s declines were especially steep in years of El Niño, and from 1990 on there was no recovery even when the oceanographic pendulum swung the opposite direction (Oedekoven et al. 2001). Evidently much of the population has shifted farther north, into the north-central Pacific (Spear and Ainley 1999), but the species’ total numbers may be declining as well (Oedekoven et al. 2001). The Sooty Shearwater offers the most striking example of how suddenly and profoundly a bird’s distribution can be affected by climate change. It stands as a warning of how quickly anthropogenic global warming could render many places unsuitable for even their most abundant wildlife.
Short‑tailed Shearwater Puffinus tenuirostris
Unlike other seabirds that breed in the southern hemisphere and migrate to the North Pacific, the Short-tailed Shearwater occurs off California mainly in the northern winter. Off San Diego County it is generally uncommon to rare, though influxes of larger numbers are known in at least two winters. Like the Black-vented Shearwater, the Short-tailed prefers waters rather close to shore; it is seen typically within 5 miles of the coast.
Winter: A winter day’s trip by boat into the Short-tailed Shearwater’s preferred zone often yields one or two individuals. Seven off Oceanside (H5) 24 December 1988 (D. W. Povey, AB 43:365, 1989) and 10 off La Jolla (P7) 1 January 1999 (G. McCaskie, NAB 53:208, 1999) were high numbers for most years. Irruptions took place, however, in 1941–42 and 1983–84. In the former winter, Kenyon (1942, 1943) saw at least 120 one quarter mile off La Jolla 16 December 1941 and collected 18 specimens, both at sea and as beached casualties. In the latter, McCaskie saw 75 off San Diego 21 January 1984 (AB 38:357, 1984) and one was picked up dead on shore at Imperial Beach (V10) 1 December 1983 (SDNHM 43349). Because of the species’ typically inshore distribution, it has been seen from shore on numerous occasions, with up to six at La Jolla 9 December 2001 (S. Walens).
Migration: Dates for the Short-tailed Shearwater in San Diego County extend from 19 October (1983, two off San Diego, D. W. Povey, AB 38:246, 1984) to 28 April and 2 May (1997, individuals found sick or dead on the beach at Coronado, T9, B. Foster, E. Copper, FN 51:927, 1997; specimens not saved).
Manx Shearwater Puffinus puffinus
The Manx Shearwater, a close relative of the Black-vented Shearwater, nests on islands in the North Atlantic and winters along the coast of southern South America. Apparently some birds have rounded Cape Horn and migrated to the North Pacific, accounting for over 75 well-supported sightings off California through 2002. These records are all since 1993, suggesting a shift in the species’ distribution—possibly a still-undiscovered colonization of the Pacific Ocean—as well as birders’ becoming aware of the species and its identification criteria.
Migration: The first Manx Shearwater conclusively identified near San Diego County was 16 miles off Oceanside 28 April 2004 (T. McGrath).
Black‑vented Shearwater Puffinus opisthomelas
The ocean along San Diego County’s coast is central to the nonbreeding range of the Black-vented Shearwater. At times, much of the population concentrates there, feeding on squid and fish. The Black-vented Shearwater nests in spring on islands around Baja California, principally Natividad, then migrates north, occurring off southern California primarily in fall and winter.
Winter: The Black-vented is less pelagic than most other shearwaters, concentrating within 15 miles of the coast. Briggs et al. (1987), however, recorded it out to the Santa Rosa–Cortés Ridge, 100 miles offshore. In the mid to late 1970s, they found the species most consistently in a strip from San Diego north about 75 km—essentially, the San Diego County coastline—and their highest densities, up to 80 birds per square kilometer, off Oceanside. When sardines or squid are concentrated, however, the numbers of Black-vented Shearwaters can be far higher, for example, 10,000 off San Diego 19 October 1983 (D. W. Povey, AB 38:246, 1984). Often the birds can be seen (with aid of a scope) in large numbers from shore. Our largest such count during the atlas period was of 3850 off Torrey Pines State Reserve (N7) 23 December 2001 (S. Walens). All these counts, however, were eclipsed on 23 and 24 January 2004. On the morning of the 24th, about 85,000 were off La Jolla (N7; S. Walens) while 30,000–50,000, possibly part of the same flock, were off Cardiff (L7; P. A. Ginsburg). The spectacle was broadcast on television news. These flocks must have constituted a substantial fraction of the world’s Black-vented Shearwaters, given that the population breeding in 1997 on Natividad Island was about 77,000 pairs, and that island supports 95% of the species’ entire population (Keitt et al. 2003). An abundance of juvenile sardines, observed by local bait seiners, probably attracted the shearwaters that day (S. E. Smith, National Marine Fisheries Service).
Migration: In general, the Black-vented Shearwater is most abundant off southern California from September through December (Briggs et al. 1987). Its movements vary, however, from year to year. Especially in years of El Niño, when the nesting of many seabirds around Baja California fails because of a shortage of food, Black-vented may arrive early, as in late July 1983, when hundreds were visible from La Jolla (G. McCaskie, AB 37:1026, 1983), and 7–9 July 1992, when 500 were in the same area (P. A. Ginsburg, AB 46:1177, 1992). Briggs et al. (1987) saw no Black-vented Shearwaters off southern California in April, but, on occasion, the species occurs in numbers in San Diego County even then, with up to 500 at La Jolla 7 April 2001 (S. Walens).
Conservation: Because the Black-vented Shearwater is so concentrated in both its nesting colony and pelagic range, it is especially vulnerable to disasters like oil spills that could kill most of the population quickly. Inclusion of Natividad Island in the Vizcaíno Biosphere Reserve and the recent eradication of cats, goats, and sheep from it were major steps toward safeguarding the species. But many threats remain, because of establishment of a human settlement on the island, the driving of vehicles through the colony, and the constant danger that other mammals could escape and establish themselves. Because the colony has been censused adequately only once, the population trend is still unknown (Keitt et al. 2003).
Veit et al. (1996) found the Black-vented Shearwater’s numbers off southern California increasing in response to ocean warming, so the recent high numbers suggest continuation of a trend.