Northern Saw-whet Owl

Northern Saw-whet Owl
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Strigiformes
Family: Strigidae
Genus: Aegolius
Species: A. acadicus
Binomial name
Aegolius acadicus
(Gmelin, 1788)
Subspecies

Aegolius acadicus acadicus
Aegolius acadicus brooksi

The Northern Saw-whet Owl (Aegolius acadicus) is a small owl native to North America.

Contents

Description

The scientific description of one of the sub-species of this owl is attributed to the Rev. John Henry Keen who was a missionary in Canada in 1896.[2] Adults are 17–22 cm (6.7–8.7 in) long with a 42–56.3 cm (17–22.2 in) wingspan.[3][4] They can weigh from 54 to 151 g (1.9 to 5.3 oz) with an average of around 80 g (2.8 oz),[5][6] making them one of the smallest owls in North America.[7] In relative size to other birds they are close to the size of an American Robin. The Northern Saw-whet Owl has a round, light, white face with brown and cream streaks; they also have a dark beak and yellow eyes. They resemble the Short-eared Owl, because they also lack ear tufts, but are much smaller. The underparts are pale with dark shaded areas; the upper parts are brown or reddish with white spots. They are quite common, but hard to spot.

Voice

The Northern Saw-Whet Owl makes a repeated tooting whistle sound. Some say they sound like a saw being sharpened on a whetstone.[8] They usually make these sounds to find a mate, so they can be heard more often April through June when they are looking for mates. Despite being more common in Spring, they do vocalize year round.

Habitat

Their habitat is coniferous forests, sometimes mixed or deciduous woods, across North America. They also love riparian areas, nears streams and rivers because of the abundance of prey in those areas. [9] They live in tree cavities and old nests made by other small raptors. Some are permanent residents, while others may migrate south in winter or move down from higher elevations.Their range covers most of North America including Southeastern Alaska, Southern Canada, most of the United States and the central mountains in Mexico. The map shows where they breed and the areas where they can live throughout the year.

Some have begun to move more southeast in Indiana and neighboring states. Buidin et. al. did a study of how far north the Northern Saw-whet owls breed and they found that they can breed northward to >50[degrees] N, farther than ever recorded before.[10] Their range is quite extensive and they can even breed in the far north where most birds migrate from to breed. They are an adaptive species that can do well in the cold.

Nesting

Northern Saw-Whet Owls lay about 5-6 white colored eggs in natural tree cavities or woodpecker holes. The father does the hunting while the mother watches and sits on her eggs. Females can have more than one clutch of eggs each breeding season with different males. Once the offspring in the first nest have developed their feathers the mother will leave the father to care for them and go find another male to reproduce with. [11] This type of mating is sequential polyandry.

Feeding

These birds wait on a high perch at night and swoop down on prey. They mainly eat small organisms such as small birds, mice, and the occasional chipmunk. On the Pacific coast they may also eat crustaceans and aquatic insects. Like many owls, these birds have excellent hearing and exceptional vision in low light. In a test done by Swengel and Swengel they found that the Northern Saw-Whet Owls most often eat deer mice, 67% and voles, 16% of the time in Wisconsin. [12] . In a similar test done by Holt and Leroux in Montana found that these owls ate more voles than other mammals. [13] This shows that these owls can change their main prey depending on what is available. Also researched by Holt and Leroux was the eating habits of Northern Saw-Whet owls and Northern Pygmy Owls and found that they prey on different animals for their main food source, showing that they can adapt not only depending on the prey but also with the other predators in the areas where they live.

In popular culture

Martin from the "Guardians of Ga'Hoole" novel series is a Northern Saw-whet Owl.

The song of the Saw-whet Owl is mentioned in the Grateful Dead song "Unbroken Chain" on their album Grateful Dead from the Mars Hotel.[14]

After an online "Critter Vote", the Saw-whet Owl became the new star of Telus' mobility campaign in the summer of 2011.

References

  1. ^ BirdLife International (2008). Aegolius acadicus. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 24 February 2009.
  2. ^ Beolens et al, Bo (2009). The Eponym Dictionary of Mammals p.220. JHU Press. pp. 574. http://books.google.com/books?id=I-kSmWLc6vYC&lpg=PA220&dq=rev%20john%20henry%20keen&pg=PA220#v=onepage&q=rev%20john%20henry%20keen&f=false. 
  3. ^ [1] (2011).
  4. ^ [2] (2011).
  5. ^ Sibley, David (2003). The SibleyField Guide To Birds of Eastern North America. New York: Alfred A. Knopf. p. 229. ISBN 0-679-45120-X. 
  6. ^ CRC Handbook of Avian Body Masses by John B. Dunning Jr. (Editor). CRC Press (1992), ISBN 978-0849342585.
  7. ^ Vanner, Michael (2003). The Encyclopedia of North American Birds. New York: Barnes&Noble. p. 192. ISBN 0-7607-3460-7. 
  8. ^ Bull, John; Farrand, Jr., John (1994). National Audubon Society Field Guide to North American Birds. New York: Alfred A. Knopf. p. 555. ISBN 0-679-42852-6. 
  9. ^ DeLella Benedict, Audrey (2008). The Naturalist's Guide to the Southern Rockies: Colorado, Southern Wyoming, and Northern New Mexico. Golden, Colorado: Fulcrum Publishing. pp. 568. ISBN 978-1-55591-535-3. 
  10. ^ Buidin, Christophe; Yann, Rochepault, Jean-Pierre L. Savard, Michel Savard (2006-09). "Breeding range extension of the Northern Saw-whet Owl in Quebec". The Wilson Journal of Ornithology 118 (3): 411. 
  11. ^ DeLella Benedict, Audrey (2008). The Naturalist's Guide to the Southern Rockies: Colorado, Southern Wyoming, and Northern New Mexico. Golden, Colorado: Fulcrum Publishing. pp. 568. ISBN 978-1-55591-535-3. 
  12. ^ Swengel, Ann B.; Scott R. Swengel (1992-08). "Diet of Northern Saw-whet Owls in southern Wisconsin". The Condor 94 (3): 707. 
  13. ^ Holt, Denver W.; Leslie A. Leroux (1996-03). "Diets of Northern Pygmy-Owls and Northern Saw-whet owls in West-Central Montana". Wilson Bulletin 108 (1): 123. 
  14. ^ Dodd, David. "The Annotated "Unbroken Chain"". "The Annotated Grateful Dead Lyrics". http://artsites.ucsc.edu/GDead/agdl/chain.html#owl. Retrieved 27 September 2010. 

External links