Fr: Guillemot de Craveri
Ang: Craveri’s Murrelet
All: Craverialk
Esp: Mérgulo Californiano Alioscuro
Ita: Urietta di Craveri
Nd: Craveri's Alk
Sd: Sotvingad californiaalka
Text and illustration by Nicole Bouglouan
Sources :
HANDBOOK OF THE BIRDS OF THE WORLD Vol 3 by Josep del Hoyo-Andrew Elliott-Jordi Sargatal - Lynx Edicions - ISBN: 8487334202
OISEAUX DE MER – Guide d’identification de Peter Harrison – Editions Broquet (Canada) – ISBN-10 : 2890004090 – ISBN-13 : 978-2890004092
FIELD GUIDE TO THE BIRDS OF NORTH AMERICA - National Geographic Society - ISBN: 0792274512
A GUIDE TO THE BIRDS OF MEXICO AND NORTHERN CENTRAL AMERICA by Steve N. G. Howell, Sophie Webb - Oxford University Press - ISBN: 0198540124
Wikipedia, the free encyclopaedia
What Bird-The ultimate Bird Guide (Mitchell Waite)
Neotropical Birds – Cornell Lab of Ornithology
SORA Searchable Ornithological Research Archive (Blair O. Wolf)
THE TYPE LOCALITY OF CRAVERI’S MURRELET
Biodiversity, Ecosystems, and Conservation in Northern Mexico Publié par Jean-Luc E. Cartron,Gerardo Ceballos,Richard Stephen Felger
Craveri’s Murrelet
Synthliboramphus craveri
Charadriiformes Order – Alcidae Family
INTRODUCTION:
The Craveri’s Murrelet is very similar to Scripps’s Murrelet and Guadalupe Murrelet in habits and appearance. It breeds on small islands off Baja California and forms loose colonies. Its breeding range may overlap on San Benito Islands with that of Guadalupe Murrelet, but there is no evidence of hybridization.
Like other Alcidae nesting on islands, it is threatened by introduced mammalian predators and other usual threats such as oil pollution and disturbance at colonies, involving significant declines of the population.
The Craveri’s Murrelet is currently classified as Vulnerable and is probably one of the more endangered species within the family Alcidae.
The name of this species pays tribute to Federico Craveri, an Italian chemist living in Mexico City in 1855. He was commissioned by the Mexican Government to assess the resources of the guano islands in NW Mexico. Several avian specimens were collected in addition to analysing the guano, including four species of murrelets. One of which was described as Craveri’s Murrelet by Tommaso Salvadori in 1865, an Italian ornithologist.
DESCRIPTION OF THE BIRD:
Biometrics:
Length: 21-22 cm
Wingspan: 38 cm
Weight: 128-150 g
The Craveri’s Murrelet is a small, black and white seabird. The upperparts are black slightly tinged brownish on head, rear neck, back, rump, wings and tail.
The underparts are white with blackish partial collar ending on breast sides. Flanks are blackish too. The underwing is dusky with whitish median patch.
On the head, the black crown extends from under the base of the bill, through and below the eye to nape and rear neck. Chin, throat and lower sides of face are white.
The black bill is slightly slimmer and longer, but less robust than in Guadalupe Murrelet. The eyes are dark brown with two white crescents, one above and the other below, like a broken eyering. Legs and webbed feet are bluish-grey with black claws.
Male and female are similar and there is no seasonal variation.
The juvenile resembles adult but it has shorter bill and darker upperparts, whereas sides of breast and belly show narrow dark bars or spots.
RANGE:
The Craveri’s Murrelet breeds on several small rocky islands along the coast of Baja California, both in Gulf of California and Pacific coasts.
It winters at sea in Gulf of California and along the coasts N to S California (Monterey Bay) and S to W Mexico.
HABITAT:
The Craveri’s Murrelet breeds on rocky islands and islands with dense vegetal cover to protect the nest-sites. It nests on steep sea cliffs and slopes.
During winter, it can be seen offshore, but it remains close to its breeding range. It may occur far from shores in the pelagic waters of the Californian Current that are locally warmer due to the Davidson Current.
CALLS AND SONGS: SOUNDS BY XENO-CANTO
The Craveri’s Murrelet utters a cicada-like rattle rising to a reedy trilling when the bird is alarmed or excited.
BEHAVIOUR IN THE WILD:
The Craveri’s Murrelet feeds on small-sized aquatic prey including larval and adult fish (40/70 mm) such as herring, rockfish (Sebastidae) and lanternfish (Myctophidae).
It forages by diving and swimming underwater, propelled by wings and webbed feet. The prey is pursued with powerful wingbeats through the water. It often forages alone or in pairs, occasionally in loose small groups.
The mating system of the Craveri’s Murrelet is poorly known, but they are probably monogamous with long-term pair-bonds. Like numerous Alcidae, it is active at night at the colony.
It nests in cavities, rocky crevices or at base of shrub. It breeds in small colonies/groups, usually at low density.
The Craveri’s Murrelet begins to arrive in the Gulf of California in January, and the pairs are probably formed. After breeding, they disperse in June/July, but the main movements N occur between August and October off the Pacific coast of Baja California N to S California (Monterey) and some move S to W Mexico.
The Craveri’s Murrelet has low, direct flight over water, with rapid wingbeats.
REPRODUCTION OF THIS SPECIES:
The breeding sites are occupied in early February and the peak laying takes place in late February/early March. The nesting period extends to early April.
The Craveri’s Murrelet breeds in small, scattered groups and at low density, due to the reduced suitable nesting habitat. It is nocturnal at colonies.
It nests on rocky islands in rock crevices or abandoned burrows, just above the high-tide mark, often under dense shrubs and boulders.
The female lays 2 eggs directly on the ground. Both adults share the incubation during 30-33 days. At hatching, the chicks have dark down above and white below. They are precocial and mobile but flightless. As usual, they remain 1-2 days at nest and are not fed. Then, they are taken by their parents and the family group reaches the ocean. The chicks are fed with larval and small fish. They still depend on parents for some weeks or months, but time to independence is unknown.
PROTECTION / THREATS / STATUS:
The Craveri’s Murrelet is threatened by natural and introduced predators on their breeding islands. Mammalian predators such as rodents and cats take both eggs and chicks, whereas Peregrine Falcon, Common Barn Owl and gulls take both adults and young.
This species is also vulnerable to oil spills and fishing nets at sea, and disturbance at breeding colonies.
The population is estimated to number 9,000/15,000 individuals, equating to 6,000/10,000 mature individuals. This population is suspected to be declining throughout the range.
The Craveri’s Murrelet is currently classified as Vulnerable.