Black Storm-Petrel

Oceanodroma melania


Demography and Populations

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Figure 3. Distribution of Black Storm-Petrel nesting colonies.

Locations of confirmed Black Storm-Petrel nesting colonies.(1—Santa Barbara Island and Sutil Island; 2—Islas Coronado; 3—Islas San Benito; 4—Islas Cardinosa and Cardinosita (= Partida); 5—Islas San Luis; 6—Roca Consag; 7—Isla San Esteban; 8—La Lobera and Isla Partida at Isla Espíritu Santo.

Measures of Breeding Activity

Age at First Breeding; Intervals Between Breeding

Not known. Likely 4–6 years of age (earliest 3 years), as in Leach's Storm-Petrel (Oceanodroma leucorhoa; 3) and Ashy Storm-Petrel (O. homochroa; 88). Probably breeds annually, but could skip years, particularly when ocean conditions are anomalous (El Niño).


One egg/clutch; 1 clutch/yr (73, 1). In an unknown proportion of cases among other storm-petrels, replacement egg laid if first egg lost (e.g., 2, 3).

Annual and Lifetime Reproductive Success

In a 2-year study at Islas Coronado, Everett (1) observed the following rates (occupied nests, n = 38 in 1989, 26 in 1990): eggs laid, 97, 68% of nests; eggs hatched, 55, 50%; chicks fledged of eggs hatched, 81, 100%; chicks fledged of eggs laid, 45, 50%. In a 3-year study of occupied nests at Islas San Benito (2012–2014, n = 39–56 nests): eggs hatched, 72–82%; chicks fledged of eggs hatched, 71–87%; chicks fledged of eggs laid, 63–67% (Y. Bedolla-Guzmán, J. F. Masello, A. Aguirre-Muñoz, B. E. Lavaniegos, and P. Quillfeldt, unpublished data; see also 89 and Table 1). Rates for hatching success and chicks fledged significantly lower than for Ashy Storm-Petrel on Farallon Islands (off San Francisco; 2).

No data on lifetime reproductive success.

Number of Broods Normally Reared per Season


Proportion of Total Females That Rear at Last One Brood to Nest-Leaving or Independence

No information.

Life Span and Survivorship

Not known.

Disease and Body Parasites

On Islas Coronado in Baja California, Everett (1) reported one 4-wk-old chick (out of several dozen handled during a 2-year study) that had 12–15 fleas (Actenopsylla suavis). The same flea species was reported from Cassin's Auklets (Ptychoramphus aleuticus) at this locality. Feather lice and mites are common on old chicks (YBG). No information on disease. Hepatozoon peircei sp. nov. was recently found to be infecting erythrocytes, rather than leucocytes, in Black Storm-Petrels (90).

Causes of Mortality

Predation by Peregrine Falcon (Falco peregrinus), Common Raven (Corvus corax), and gulls, including Western Gull (Larus occidentalis) and Yellow-footed Gull (L. livens); 43, 1, 45, 64, 91, YBG); by feral cats (Felis catus) and rats (Rattus spp.; 48, 44, 49, 64); by foxes (Urocyon littoralis) and skunks (Spilogale gracilis amphiala) (64); as well as by owls (Tyto alba; 70). Impalement occurs on the spines of cactus and other plants (48, 30, 92). Other causes not known. See Behavior: Predation.


Initial Dispersal From Natal Site

Not known.

Fidelity to Breeding Site and Overwintering Home Range

No data. Probably highly philopatric to breeding site but, given large variation in numbers overwintering farthest north or south in range, may not show fidelity to overwintering range (see Distribution: Marine Range).

Dispersal From Breeding Site or Colony

Degree of dispersal in winter a function of oceanographic conditions. Disperses more widely during El Niño, judging from more northerly movements of the population along the West coast of the United States during those conditions (57; Distribution: Marine Range).

Home Range

Adults probably forage fairly closely to the colony (i.e., within a few hundred kilometers); in a study at Islas San Benito, stable-isotope analysis and a marine isoscape indicated that Black Storm-Petrel forages in coastal areas, at least 200 km away (Y. Bedolla-Guzmán, J. F. Masello, A. Aguirre-Muñoz, B. E. Lavaniegos, and P. Quillfeldt, unpublished data). Density at sea during summer is inversely related to distance from colony (7). This is judged from similarity in time of arrival in the evening to Ashy Storm-Petrel, a close-to-colony forager (79). On the other hand, Black Storm-Petrel is a much stronger flier than Ashy Storm-Petrel and thus could travel longer distances in the same amount of time.

Population Status


Estimates available for only a few locations among those where breeding is known (see Table 1). Occurs on all three of the Islas San Benito (Pacific Coast, Baja California); population there may exceed one million pairs (probably an overestimate owing to difficulty in distinguishing breeders from nonbreeders). See Figure 3 for colony locations. On the basis of at-sea surveys (1980–1995), with 1,098 and 845 individuals sighted during 23 cruises in the eastern Pacific (not including Gulf of California), 441,400 individuals (95% CI = 350,000–570,000) in boreal spring, and 561,700 (95% CI: 480,000–690,000) in autumn were estimated (93).


Since 1980, the number of Black Storm-Petrels seen in vicinity of Islas Coronado have decreased (49). An increase in observations in waters of southern and central California (United States) during recent years may be a response to shifting marine climate, rather than a change in the breeding population; during the last 1,500 years, may have bred on Santa Barbara Island only within last 100 years (70); see Distribution, Migration, and Habitat: Distribution in the Americas: Marine Range).

Population Regulation

The population was formerly limited at Islas Coronado by availability of suitable nesting habitat free of introduced feral cats (Felis catus) and other native and non-native predators (1). Cats have been removed from both Isla Coronado Norte and Isla Coronado Sur (83), which should improve nesting opportunities. Limitation by introduced predators likely true from the larger perspective of the entire population considering all used and potentially used nesting localities. Owing to introduction of predatory mammals to breeding islands, world population now likely much smaller than before Europeans arrived. The endemic island gray fox (Urocyon littoralis) and island spotted skunk (Spilogale gracillis amphiala), found only on Santa Cruz and Santa Rosa Islands, in California Channel Islands, could have limited presence among Channel Islands except Anacapa Island, Santa Barbara Island and Sutil Rock during prehistoric times; however, on all the islands, some habitat exists on sheer cliff faces and in sea caves that would have been inaccessible to these predators (44, 64).

Recommended Citation

Everett, W. T., Y. R. Bedolla-Guzmán, and D. G. Ainley (2019). Black Storm-Petrel (Oceanodroma melania), version 2.0. In The Birds of North America (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.