Guadalupe Murrelet

The Guadalupe murrelet, known scientifically as Synthliboramphus hypoleucus, is a diminutive seabird adorned in a contrasting plumage of black and white. It possesses a petite head and a slender, sharp bill, characteristic of its kind.

Identification Tips

When endeavoring to identify this small auk, one should note its black upperparts and white underparts, as well as its small stature and pointed bill. It bears a resemblance to its close relatives, the Scripps's and Craveri's murrelets.

Habitat

This bird selects the arid islands off the coasts of California and Mexico for its breeding grounds, favoring secluded crevices, caves, and dense shrubbery for nesting.

Distribution

The Guadalupe murrelet breeds on islands from Guadalupe Island southward to the San Benito Islands. Post-breeding, it disperses at sea, extending its range northward up to southern California.

Behaviour

The Guadalupe murrelet is a pelagic feeder, often seen in the company of large predatory fish such as tuna, from which it likely gains protection and foraging opportunities. It dives with vigorous wingbeats to pursue larval fish, including anchovies, sardines, and Sebastes rockfish. Notably, it is almost invariably observed in pairs, suggesting potential cooperative behavior. This bird is also adept at flight, capable of taking to the air without the need for a running start.

Breeding

The species is nocturnal when visiting its breeding colonies, where it lays two eggs. The incubation period lasts approximately one month. Remarkably, the chicks are highly precocial, vacating the nest within two days of hatching and energetically making their way to the sea, guided by the calls of their parents.

Conservation status

The Guadalupe murrelet is classified as Endangered. It faces significant threats from oil spills, particularly given its proximity to major shipping lanes. Additionally, introduced predators such as rats and feral cats have historically posed a risk, although conservation efforts to remove these predators have mitigated this threat to some extent.

Diet and Feeding

The diet of the Guadalupe murrelet consists primarily of larval fish, which it captures by diving underwater using its wings to propel itself.

Similar Species

This species was once considered conspecific with the Scripps's murrelet, but they have since been recognized as distinct due to differences in facial patterns, bill shape, vocalizations, and genetics. When identifying the Guadalupe murrelet, one should carefully distinguish it from the Scripps's and Craveri's murrelets, which share its southern range.

In the vastness of the Pacific Ocean, the Guadalupe murrelet persists, a testament to the resilience of nature amidst human encroachment and environmental challenges.