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Sanctuary Rocky
Intertidal Open
Ocean & Endangered
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Año Nuevo Island
In the early hours of a calm, clear morning, the view of Año Nuevo Island from the mainland reserve is one of apparent tranquility. The slow rumble of breaking surf may mask the cacophony of sounds, the outline of a single lumbering sea lion may distract from the carpet of pinnipeds beneath. The island is in fact teeming with creatures trying to take advantage of prime real estate. Over the past thirty years, while the island itself has noticeably decreased in size, its attraction as a hotspot for seabirds and pinnipeds has continued to grow. As long as there have been systematic monitoring efforts, the island has been used for breeding by four species of sea and shore birds. Western Gulls are by far the most populous of the feathered contingent, their nests dominating the majority of the island's terrace. Approximately 800 pair build nests on vegetated areas, dirt patches, boardwalks, and structures left behind by previous human visitors. In recent years, Westerns have even spilled over onto the island's beaches, though nests are vulnerable to trampling by pinnipeds and high tide flooding. About twenty to thirty Pigeon Guillemots make their reproductive living in the small cracks of the island's protected cliffs. A few find their way into nest boxes recently erected for other seabird species. This preference for crevices means that guillemots do not compete for space with gulls, but also that the island's population is limited by habitat availability. Counts during the 1970s revealed sixty to eighty nesting birds; the currently lower numbers may reflect the considerable erosion that the island has suffered in the past twenty years.
Pelagic Cormorants also utilize a unique nesting habitat, generally
preferring narrow cliff edges. About ten pair have found a suitable
substitute along the eaves of the old lighthouse keeper's residence,
a once-grand two-story house abandoned in 1948. Erosion may take
its toll on these subtidal foragers as well: last winter saw the
northeast foundation of Black Oystercatchers are the fourth long-time resident breeders of Año Nuevo Island. They prefer to lay their cryptic eggs in driftwood clumps high on the island's beaches. Their abundance is limited because they establish large territories during much of the year. Less than ten pair nest on the island, and they face the growing pressures of predation by gulls and disturbance by pinnipeds. While those seabirds in the minority work to maintain their foothold, the past two decades have brought four new arrivals to the Año Nuevo Island breeding scene. In the mid-1980s, Rhinoceros Auklets began establishing a presence on the island, each pair digging a burrow in which to lay their single egg. These birds were once very abundant along the West Coast, but by the 1860s had disappeared in California. In the 1960s, rhinos returned to the nearby Farallones, and have since made their way to Año Nuevo. To encourage their recovery, researchers have installed more than fifty nest boxes around the island. This additional habitat appears to be a successful conservation tool -- about fifty to ninety pair have nested on the island in recent years. The Brandt's Cormorant has also joined the ranks of recent arrivals.
Beginning in 1994, breeders established a colony that has since
grown to approximately 400 pairs. Their success can be attributed
to mobs of aggressive males that arrive early in spring, displacing
gulls and stealing nest material. Brandt's nest only a neck-length
apart, excluding other species that wish to compete for habitat.
Since the 1970s, Brandt's Cormorant colonies have declined on
the Farallones, their main breeding grounds. Año Nuevo
may represent an area of abundant resources where adventuresome
pairs can establish themselves and thrive. Finally, a lone pair of courageous Heerman's Gulls have braved
the challenge of reproducing amongst the larger Western Gulls.
Since the mid-1990s, what is believed to be the same pair has
returned repeatedly in an attempt to raise their young. To date,
they have successfully fledged chicks only in 1996, but the occasion
represented the first record of Heerman's breeding in northern
California. The disappearance and return of the northern elephant seal, however, is an entirely certain story. Due to unrelenting sealing pressure during the first half of the 1800s, these huge lumbering creatures were presumed extinct by 1869, even though breeding rookeries had ranged from Point Reyes to Baja California. A remnant population hidden on Guadalupe Island has since made a remarkable comeback, bringing the total population to more than 140,000. The first two pups born were born at Año in 1961, and today about 500 females give birth on the island. While elephant seals blanket the beaches during winter, summer is the season for Steller sea lion reproduction. Researchers estimate 160 to 180 pups born this past year; unfortunately, Año is a fragile outpost for this threatened species, as their numbers have been declining on the island in recent years. Finally, a small but stable group of about fifteen harbor seals also share the island for birthing grounds.
Though they do not use the island for reproductive reasons, two other species deserve mention because their presence can be so overwhelming during late summer. Both California sea lions and California Brown Pelicans journey up the coast as their breeding seasons wane in southern and Baja California. The signature barks of more than 10,000 sea lions drown out much of the island's activity, and individuals can even be seen hauled out on top of male elephant seals, for lack of beachfront property. They have taken over the lighthouse keeper's residence, their agility allowing them to master the staircase to the second floor. Between 1,000 and 3,000 pelicans arrive during this same period, roosting on any available space that they can find amongst the last of the breeding seabirds. While one cannot miss the arrival of sea lions and pelicans, one last creature is often cruising the island's waters unnoticed. The white shark population peaks between October and February, when elephant seals are most abundant. Local researchers have tagged more than fifty sharks in recent years, and have learned that most of them are adult females over fifteen feet long! Though individual sharks only stay in the area for a few weeks each season, several sharks have returned for winter meals year after year. Though each species has its own story, Año Nuevo Island
may be most fascinating for the multitude and complexity of interactions
that govern its residents' lives. The bustle of thousands of huge
pinnipeds produces constant pressures on seabirds trying to maintain
breeding habitat. The seabirds themselves must fight for space
and nesting material, both within and among species. Meanwhile,
all of the island's inhabitants are subject to the powers of wind
and waves, which are continually stealing pieces of the tiny haven
treasured by so many.
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For comments or question please refer to the Webmaster Last modified on: Jan 15, 2000 |
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