Glaucidium californicum

Life-forms

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Infraclassis: Archosauromorpha
Cladus: Crurotarsi
Divisio: Archosauria
Cladus: Avemetatarsalia
Cladus: Ornithodira
Subtaxon: Dinosauromorpha
Cladus: Dinosauriformes
Cladus: Dracohors
Cladus: Dinosauria
Ordo: Saurischia
Cladus: Eusaurischia
Subordo: Theropoda
Cladus: Neotheropoda
Cladus: Averostra
Cladus: Tetanurae
Cladus: Avetheropoda
Cladus: Coelurosauria
Cladus: Tyrannoraptora
Cladus: Maniraptoromorpha
Cladus: Maniraptoriformes
Cladus: Maniraptora
Cladus: Pennaraptora
Cladus: Paraves
Cladus: Eumaniraptora
Cladus: Avialae
Infraclassis: Aves
Cladus: Euavialae
Cladus: Avebrevicauda
Cladus: Pygostylia
Cladus: Ornithothoraces
Cladus: Ornithuromorpha
Cladus: Carinatae
Parvclassis: Neornithes
Cohors: Neognathae
Cladus: Neoaves
Ordo: Strigiformes

Familia: Strigidae
Subfamilia: Surniinae
Genus: Glaucidium
Species: Glaucidium californicum
Subspecies: G. c. californicum – G. c. grinnelli – G. c. pinicola – G. c. swarthi
Name

Glaucidium californicum P.L. Sclater, 1857
Synonyms

Glaucidium gnoma californicum P.L. Sclater, 1857
Phalaenopsis californica (P.L. Sclater, 1857)

References

Sclater, P.L. 1857. Notes on the Birds in the Museum of the Academy of Natural Sciences of Philadelphia, and other Collections in the United States of America. Proceedings of the Zoological Society of London Pt.25 no.327: 1–8. BHLReference page. p. 4 BHL

Vernacular names
čeština: Kulíšek západní
English: Northern Pygmy-Owl
español: Mochuelo californiano
polski: sóweczka kalifornijska

The northern pygmy owl (Glaucidium californicum) is a small owl native to western North America.
Taxonomy

Some taxonomic authorities, including the International Ornithologists' Union, separate this species from the mountain pygmy owl, the Baja pygmy owl, and the Guatemalan pygmy owl, while others, such as the American Ornithological Society, do not recognize the split and consider this bird conspecific with the group, with the northern pygmy owl taking the English name for them all. Furthermore, if the group is considered conspecific, G. gnoma becomes the scientific name because it is older. Clear differences in the territorial calls by males are the basis for the proposed split, with birds in the high elevations of Arizona and Mexico giving a two-note call while their more northerly congeners give a repeated single-note call. Results from DNA sequence comparisons of cytochrome-b have been weak and inconclusive despite being referenced repeatedly as a justification for taxonomic splitting.[3]
Subspecies

There are four recognized subspecies:

G. c. californicum (PL Sclater, 1857) – Pacific pygmy owl – central British Columbia to southwestern United States and northwestern Mexico
G. c. grinnelli (Ridgway, 1914) – Coastal pygmy owl – coniferous forests of southeastern Alaska to northern California
G. c. pinicola (Nelson, 1910) – Rocky Mountain pygmy owl – Rocky Mountains in west central United States
G. c. swarthi (Grinnell, 1913) – Vancouver Island pygmy owl – Vancouver Island in British Columbia

Description
Pacific pygmy owl with eyespots behind head

Adults are 15–17 cm (5.9–6.7 in) in overall length and are gray, brownish-gray or rufous in colour. This owl has a round white-spotted head, weakly defined facial disc, and dark upper breast, wings and tail, the latter quite long compared to other owls. The eyes are yellow and the bill is yellowish-green. The bird has two black nape spots outlined in white on the back of its head, which look like eyes. The mid to lower breast is white with darker vertical streaking. Legs are feathered down to the four well-armed toes on each foot.
Distribution and habitat

The northern pygmy owl is native to Canada, the United States, and Mexico.[1] Their habitat includes temperate, subtropical and tropical moist forest, savanna, and wetlands.[1]

In Oregon and Washington they are known to nest and forage in the center of dense, continuous forests, near streams.[4] An example of their habitat is Forest Park in Portland, Oregon, USA. Their breeding habitat includes open to semi-open woodlands of foothills and mountains in western North America.[4]
Behavior

Males will regularly perch at the top of the tallest available conifer trees to issue their territorial call, making them somewhat ventriloquistic in sloped landscapes, and causing distress and confusion among observers on the ground hoping to get a glimpse. They are incredibly hard to spot because of their size and color.
Breeding

They usually nest in a tree cavity and will often use old woodpecker holes. The female lays 2–7 eggs, typically 4–6. Nest tree species may include Douglas fir, western redcedar, western hemlock and red alder. Early in the breeding cycle males establish and defend a territory of perhaps 250 hectares (about 1 sq. mi.).[5]

During the breeding cycle the female incubates the eggs, broods the young and guards the nest. The male hunts, making food deliveries approximately every 2 hours. The male must feed his mate, the young (typically 5) and himself. The male hunts from dawn to dusk as the young near fledging, and during the first weeks after they leave the nest.

The young leave the nest (fledge) by making an initial flight that may be a short hop to a nearby branch, or an explosive burst into an adjacent tree where they land by grasping whatever branch is first contacted, sometimes clinging upside-down. Owls at this stage are sometimes called "branchers" for their clinging, dangling and climbing behaviors. The second day after fledging, the young gradually climb and fly upward into the forest canopy, where they spend their first few weeks, at times perched "shoulder-to-shoulder" with their siblings, begging for food.

Despite many statements in popular literature, no reliable information exists on the seasonal movements of this species. It is not known whether these pygmy-owls maintain the same territory or same mate year to year, though these questions are being investigated. Dispersal of young and influences on their mortality are also poorly known, though barred owls and spotted owls are known to prey on pygmy owls.
Feeding

Pygmy owls are purportedly "sit-and-wait" predators, though they in fact hunt somewhat actively, moving from perch to perch with short flights, and pursuing prey at all levels of forest structure. They swoop down on prey; they may also catch insects in flight. They eat small mammals, birds and large insects, and may take a variety of other vertebrates and invertebrates. Mountain pygmy owls occasionally take prey species the same size or larger than themselves (e.g. California quail); however, small to medium-sized birds and small mammals are the norm. They've been observed eating Wilson's warblers.[4] These owls are diurnal, and also active at dawn and dusk.
References

BirdLife International (2016). "Glaucidium californicum". IUCN Red List of Threatened Species. 2016: e.T61791401A95181072. doi:10.2305/IUCN.UK.2016-3.RLTS.T61791401A95181072.en. Retrieved 19 November 2021.
"Appendices | CITES". cites.org. Retrieved 2022-01-14.
Koenig, Weick and Becking. Owls: A Guide to the Owls of the World. 1999.
"Pygmy Owls". Oregon Field Guide. 2010. Retrieved 2010-02-21.

Giese, A (2003). "Breeding Season Habitat Use and Ecology of Male Mountain Pygmy Owls". Journal of Raptor Research.

Field Guide to the Birds of North America. National Geographic. ISBN 0-7922-6877-6.
Josep del Hoyo, ed. Handbook of the Birds of the World Vol 5. ISBN 84-87334-25-3.
David Allen Sibley. The Sibley Guide to Birds. National Audubon Society. ISBN 0-679-45122-6.