Glaucidium passerinum

Geographic Range

Eurasian pygmy owls ( Glaucidium passerinum ) are native to the central area of Palearctic region, but are also vagrants in Belgium and Denmark. Eurasian pygmy owls are found as far west as Norway and as far east as China, with a longitudinal range of 5º-145ºE. The north and south range can be found by the latitude of 50º-60ºN, respectively. These owls are also found in disjunct areas including Austria, Bulgaria, Czech Republic, Germany, Romania, Slovakia, Slovenia, Switzerland, and Ukraine.

• Biogeographic Regions
• palearctic palearctic
  • native native

Habitat

Eurasian pygmy owls are found in mature coniferous and montane forests. They are most commonly found in trees with broad leaves for nesting. Pygmy owls nest in natural holes or cavities that were formed by woodpeckers and clean of all debris. They usually reside in temperate areas with an elevation between 250 and 300 m, and in cool, moist areas to over 1,000 m in the Alps. They can be found in elevations as low as 180 m and as high as 2,000 m in the Rila Mountains. Eurasian pygmy owls are usually year-round residents of their selected habitats and regions, but sometimes travel due to inclement weather or too few prey. Their main habitat is fir-dominant at population level. Within their home range, the habitat is mature fir-dominant forest with grassland borders.

• Habitat Regions
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• mountains mountains

Physical Description

Eurasian pygmy owls are the smallest owl of Europe and their closest relative is the least pygmy owl ( Glaucidium minutissimum ). Eurasian pygmy owls have round, flat-topped heads. They have a white, narrow supercilia (a stripe from the beak's base to above the eye) and a prominent face that makes it appear as if they have masks around their yellow eyes. Their bills are pale yellow and do not have ear tufts. The nape disperses light. The dorsal sides of the owls are grey-brown with small white spots. The ventral portions of the owls are white with brown streaks along their stomach and brown breast. These owls are born with whitish colored down feathers. As juveniles, their feathers are darker than those of adults with some light markings. Adult lengths range from 15 to 19 cm, and their wingspans are between 32 and 39 cm. Males weigh between 47 and 72 g, whereas females weigh between 67 and 83 g.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger

Reproduction

Eurasian pygmy owls are usually monogamous and breed with the same partner each breeding season. They usually pair again in late autumn and the offspring are born in early spring. Males start singing then females join in, after which the pairs search for nests. Holes from woodpeckers are usually used for nests, but natural holes and nest boxes are also used. The nests are found 1-13m above ground.

• Mating System
• monogamous monogamous

Eurasian pygmy owls lay four to eight eggs. The abundance of voles regulates the brood size, which shows that climate affects the breeding performance of these predators. The breeding season for this species is April- July. They usually do not start incubating until the clutch is complete to ensure that the eggs hatch around the same time. Incubation usually lasts four weeks. The young have whitish down feathers that are later replaced by juvenile feathers, which are darker than those of adults. Birth mass has not been reported, but Eurasian pygmy owls reach 60% of adult weight in about two weeks. The young fledge at about a month, but still receive parental care, usually from the male, for a month or more. The young are independent between six and seven weeks old. These owls can begin breeding around the age of one year.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

Eurasian pygmy owl females incubate the eggs alone for a week or two while the males bring food to the nest. When the males arrive, the females come down to the ground from their nests to retrieve the food. The young are altricial, even though they are born with down feathers. The females keep the nest clean from debris and pellets. After about two weeks, males start to care for the young, and females leave to molt. At about six to seven weeks old, the young are independent and fledge from their nest. Both parents have a part in caring for the young until they become independent, although the males have a larger role in caring for the young.

• Parental Investment
• altricial altricial
• male parental care male parental care
• female parental care female parental care
• pre-fertilization
  • provisioning
• pre-hatching/birth
  • provisioning
    • male
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • male
  • protecting
    • male
• pre-independence
  • provisioning
    • male
  • protecting
    • male

Lifespan/Longevity

Eurasian pygmy owls are expected to live a maximum of 6 years in the wild. This species is not known to be kept in captivity.

Behavior

Eurasian pygmy owls are solitary nocturnal birds, except during breeding season. They fly and nest in tree cavities, making them arboreal. This owl species is sedentary because they don't travel unless there are limited resources (such as prey). When at rest, they bob their heads, cock their tails, and fluff the feathers on their heads. They tend to point their tails upward and wave them side-to-side. Eurasian pygmy owls usually conceal themselves with their ear tufts lifted to avoid being captured by predators and noticed by prey.

These owls usually do not migrate, but sometimes leave their current area due to inclement weather or too few prey. They mostly hunt just before sunrise and right after sunset. Their wings are not silent when flying, and this can often alert their prey when they approach. These owls cache their food in small holes.

Eurasian pygmy owls' most common calls are lengthy and occur most in early spring. Eurasian pygmy owls are usually monogamous and breed with the same partner each breeding season. They usually pair again in late autumn and the offspring are born in early spring. Males start singing then females join in, after which the pairs search for nests. The males bring food to the nests for the females and young. After about two weeks, females leave to molt and the male starts to care for young. The young fledge at one month old but still receive care from the male. The young are independent at six to seven weeks old.

• Key Behaviors
• arboreal arboreal
• flies
• nocturnal nocturnal
• motile motile
• sedentary sedentary

Home Range

Eurasian pygmy owls have a home range size that ranges between 0.4 and 6 km^2 (median=2.3 km^2). Breeding adult males have an average home range size of 0.67 km^2 (range of 0.46 to 0.98 km). In Bulgaria, there were 150-200 breeding pairs and Slovakia had 1500-2000. In Rila Mountains in Bulgaria, nine territories were recorded with an average density of 0.39 territories/km^2. In Slovakia, 75-82 territories were recorded with an average density of 0.95-1.04 territories/km^2 (Pačenovský and Šotnár, 2010). In Rhodopes, there were 150-170 occupied territories, with an average density of 0.218 territories/km^2 (Shurulinkov et al., 2007).

Communication and Perception

Eurasian pygmy owls' most common calls are lengthy and purposeful, and called most in early spring. Their common songs consist of 5 to 10 shrill whistles that increase in volume. Their song subsides and continues with 6 to 7 whistles per 10 seconds. Their calls can be heard up to 1 km away. The begging calls of the young are the same, but shorter. Acoustic signals are utilized in prey capture as well. When potential prey emits an anti-predator alarm, the owls tend to not attack the prey because the prey is aware that they are at risk. Eurasian pygmy owls use UV light to detect their prey's markings.

• Communication Channels
• visual visual
• acoustic acoustic

• Perception Channels
• visual visual
• ultraviolet
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Eurasian pygmy owls typically eat small mammals and birds, especially voles. Since they have proportionately large feet and legs, they are able to catch prey up to their own size. They mostly hunt just before sunrise and right after sunset. Although their wings are not silent when flying, their prey can often hear when they approach. Some bird prey species use a mobbing behavior to avoid being captured. They prefer to cache food in holes smaller than 55 mm and use larger ones for eating areas. Their prey ranges from 4 to 40 g with an average size of 19.2 g. The majority of birds captured are 5 to 20 g. A smaller percentage of birds are caught during winter. Some reptiles are prey of Eurasian pygmy owls, and most are common lizards ( Lacerta vivipara ). There have been 73 birds and 26 mammals recorded as prey of Eurasian pygmy owls. Snow can affect what the owls can prey upon. Whether the snow is present does not affect the hoarding of birds, but decreases the hoarding of voles. Eurasian pygmy owls begin their hoarding before the first snow falls and ends their utilization in spring.

• Primary Diet
• carnivore carnivore
  • eats terrestrial vertebrates

• Animal Foods
• birds
• mammals
• reptiles

• Foraging Behavior
• stores or caches food stores or caches food

Predation

To avoid being captured as prey, Eurasian pygmy owls conceal themselves in trees. When they become disturbed, they will wave their tails vigorously and bob their heads. Larger owls are predators of the Eurasian pygmy owl. One specifically listed is the boreal owl ( Aegolius funereus ).

Ecosystem Roles

Kramerella glaucidii and Dermonoton eventratus are mites that are commonly found on owl species including the Eurasian pygmy owls. Some other parasites of Eurasian pygmy owls include protozoans ( Trypanosoma avium and Plasmodium fallax ).

Economic Importance for Humans: Positive

There is no positive economic importance of Eurasian pygmy owls for humans.

Economic Importance for Humans: Negative

There is no negative economic importance of Eurasian pygmy owls for humans.

Conservation Status

The IUCN Red List states that Eurasian pygmy owls are a species of "Least Concern." On CITES, Eurasian pygmy owls are listed in Appendix II. Appendix II states that if trade is not controlled then they may become threatened. No permit to import is needed. There is no special status listed for Eurasian pygmy owls on US Migratory Bird Act, US Federal List, or the State of Michigan List.

The most serious threats to Eurasian pygmy owls are deforestation and habitat loss which can limit their lifespans. Logging caused the original population of Eurasian pygmy owls in the Black Forest in Germany to be wiped out. After captive breeding efforts, Eurasian pygmy owls were reintroduced to the area and there are now 150 breeding territories. There have been long-term banding efforts in Europe. There is also indirect protection for the Eurasian pygmy owls to help preserve habitats.

Additional Links

Encyclopedia of Life

Contributors

Sabrena Hodnett (author), Radford University, Alex Atwood (editor), Radford University, Lindsey Lee (editor), Radford University, Karen Powers (editor), Radford University, Joshua Turner (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

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