Turdus merulacommon blackbird(Also: Eurasian blackbird)

Geographic Range

The European blackbird (Turdus merula) is located primarily throughout the eastern hemisphere in the Palearctic region. It is found throughout Europe but is also located as far west as the east coast of China and as far north as the northern coast of Sweden, depending on the season. It is also found along the northern tip of Africa and along the entire coastline of Iceland. The bird was also introduced to the Australian region along the southeastern tip of Australia and New Zealand. During the breeding season, this bird is found primarily as far east as Poland, as far north as Sweden, and as far west as Yekaterinburg, Russia. It is also found in the southeastern tip of China and southern India during the breeding season. During the non-breeding season, it is primarily found in Europe but can also be found as far east as the western portion of China. With increasing urbanization, migration has become less common. Many will remain in those areas throughout the spring and summer season to reproduce. There is a heavier concentration of European blackbirds found in southern and central Europe, compared to the northern and eastern populations in Europe. (Butchart, et al., 2014; Vliet, et al., 2009)

Habitat

The European blackbird is most often found in urban areas including gardens, parks, and town shrubberies. It can also be found in farmlands with hedges and woodland areas. The concentration of the birds increases in urban areas, compared to rural areas. The increased population density is due to the greater abundance of food produced by humans. Hatchell et al. (2008) found that the blackbird was more commonly found in dense vegetation locations to build their nests. The nests of the blackbird are made out of grass, leaves, and mud. Nests are typically found in the trees at the widest part of the base, approximately 132.4 centimeters from the ground (Taberner et al. 2000). The bird is known to inhabit elevations between 900-2,300 meters. (Hatchwell, et al., 2008; Hume, 2004; Taberner, et al., 2000)

  • Other Habitat Features
  • urban
  • Range elevation
    900 to 2300 m
    2952.76 to 7545.93 ft

Physical Description

Male European blackbirds are fully black in color while the females are typically brown. The males have bright yellow or orange beaks while the female beak is brown to dark brown. The eye in the males is outlined with a bright yellow eye ring. The European blackbird weighs, on average, 102.06 grams. The blackbird is approximately 25 centimeters in length with a wingspan range between 34-38 centimeters. The hatchlings are born without feathers. (Bright and Waas, 2002; Faivre, et al., 2001)

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • Range mass
    80 to 125 g
    2.82 to 4.41 oz
  • Average mass
    102.06 g
    3.60 oz
  • Average length
    25 cm
    9.84 in
  • Range wingspan
    34 to 38 cm
    13.39 to 14.96 in

Reproduction

The European blackbird is socially monogamous throughout its lifetime. However, some male blackbirds may attempt to pursue a female that already has a mate. The blackbird typically begins mating at the age of one year.

Once a male blackbird has claimed a territory, he will defend it from competitors by running, headfirst, directly at any birds that attempts to enter. Females may also get defensive and competitive in similar ways when searching for locations to nest.

Males use a complex display when attracting females to mate. They have their beak open followed by a series of sprints and head-bows, along with a stifled song. If the female accepts this display, she will lift both her head and tail simultaneously, signaling to the male that she is ready to mate.

The coloration of beak on the male blackbird is a quality used to attract a mate. Females are typically more attracted to orange beaks because it suggests the male has favorable foraging abilities, which would be beneficial in providing for hatchlings. The coloration comes from the type and amount of carotenoids the male receives from its diet.

The nests can be found approximately 6 meters above the ground in either trees or bushes. (Bright and Waas, 2002; Preault, et al., 2005)

The weather can have an influence on when the bird chooses to start breeding, but the blackbird typically breeds between March and June. On average, the European blackbird creates 2 to 6 nests per year. Each nest contains an average of 3 eggs, and total number of eggs can be 24 per year.

Hatching occurs after approximately 13 days of incubation. The European blackbirds weigh approximately 6 grams at hatching. Typically, in about 8 days the hatchlings will begin to develop feathers in the primary and secondary areas of the wing. If a hatchling is underweight, possibly due to lack of available food, it could take an extra day or two to develop feathers.

Partecke et al. (2005) found that urban populations’ reproductive cycles are anthropogenically-influenced. The amount of unnatural light to which they are exposed is higher in these urban areas. The artificial light simulates longer days, which influences when the blackbird begins to reproduce. It can also influence when the bird begins to develop sexually. (Magrath, 2008; Snow, 1958)

  • Breeding interval
    The European blackbirs breeds 2 to 6 times yearly
  • Breeding season
    Between March and June
  • Range eggs per season
    24 (high)
  • Average time to hatching
    14 days
  • Average fledging age
    8 days
  • Range time to independence
    13 to 14 days

Most birds, including the blackbird, are altricial and require parental care for survival after hatching. Nests are usually built by the female. Both the male and female blackbird contribute to providing food, such as earthworms, for the hatchlings, however, the female is the only sex that incubates the eggs. It has been thought that males with orange beaks visit the nests more frequently than males with yellow beaks. However, Preault et al. (2005) studied an urban population in France, and found no correlation between the beak colors of the male and how frequently it visited the nest.

After approximately 13 to 14 days, the hatchlings weigh about 70 grams and are mature enough to leave the nest. Any hatchlings that die in the nest are typically removed by the mother. (Preault, et al., 2005; Snow, 1958)

Lifespan/Longevity

The longest known lifespan of the European blackbird in the wild is 21.8 years but the average lifespan is 2.4 years. It is not raised in captivity. Saether (1989) reported a positive correlation between body weight and survival rates. (; Fransson, et al., 2010; Saether, 1989)

  • Range lifespan
    Status: wild
    21.8 (high) years
  • Average lifespan
    Status: wild
    2.4 years

Behavior

The European blackbird is diurnal. It will migrate seasonally in the fall or winter season at distances of 800-2000km. The fall season includes October through November while the winter season includes December through February. Females are more likely to migrate in the fall season compared to males.

With an increase in human density and disturbance, the blackbird will frequently move to new locations in search of areas that have a smaller traffic-flow of people (Fernandez-Juricic and Telleria, 2000). Disturbances could include pedestrians, dogs (Canis lupus familiaris), and magpies, (Pica pica). The effect of disturbances includes a decrease in the amount of time spent scavenging for food.

The European blackbird is socially monogamous throughout their lifetime. The blackbird typically breeds between March and June. Nests are usually built by the female but both the male and female blackbird contribute to providing food, such as earthworms, for the hatchlings. (Fudickar and Partecke, 2012; Fudickar, et al., 2013; Karakaya and Arikan, 2015)

Home Range

The blackbird has a home range of approximately 12,700 square meters per nest. The distance from one nest to the next was, on average, at least 30 meters apart. (Karakaya and Arikan, 2015)

Communication and Perception

The European blackbird has a complex call and has the ability to change the pitch and volume depending on the environment. The blackbird has been known to adjust its pitch according to proximity to urban areas. The closer it is to noisy urbanized areas, the higher the pitch. The change in pitch is thought to be a limiting factor when finding mates for reproduction. Song frequencies between urban and rural areas differ, on average, 198 Hz (Nemeth and Brumm, 2010).

The European blackbird also changes the patterns and pitches of its songs when it is communicating the intention to fight. It is currently unknown whether it uses any chemical signals such as, pheromones. It is also unknown what kind of visual perception the blackbird possesses. (Nemeth and Brumm, 2010; Ripmeester, et al., 2007)

Food Habits

The blackbird is a frugivore and granivore. It commonly eats larger, high-energy fruits, such as the common hawthorn (Crataegus monogyna). It is known to consume species of fruits with seeds that are easily digestible with a low concentration of seeds. This bird also consumes sloe (Prunus spinose), ivy (Hedera helix), elder fruits (Sambucus nigra), bramble (Rubus fructicosa), and dogrose (Rosa canina).

The European blackbird also eats insects including beetles, caterpillars, grasshoppers, plus snails, spiders, and earthworms. Due to its close proximity to urbanized areas, it can be assumed that the bird also consumes manmade food. (Hume, 2004; Sobral, et al., 2010)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods
  • mollusks
  • terrestrial worms
  • Plant Foods
  • seeds, grains, and nuts
  • fruit

Predation

A common predator of the blackbird are Eurasian sparrowhawks (Accipiter nisus) because the European blackbird commonly searches for food located on the ground in open and unprotected areas. In the breeding season, female blackbirds tend to spend more time in search of food compared to males, which lends to the increasing amount of female deaths from predation. Other known predators include domestic cats (Felis catus), weasels and foxes. Nest predators of the blackbird include the Eurasian magpie (Pica pica), Eurasian jay (Garrulus glandarius), and the garden dormouse (Eliomys quercinus). (Post and Gotmark, 2006)

Ecosystem Roles

The European blackbird provides seed dispersal of wild cherry trees (Prunus avium) by regurgitating the seeds after consuming the fruit. It is common to find the parasite known as bird blowfly (Trypocalliphora braueri) in the nests of the European blackbird. The parasite larvae have been found to affect the growth and survival rates of the nestlings. It has also been linked to anemia (Lucenicova et al. 2014). Other parasites that the blackbird encounters are ticks from the genus Ixodes. The presence of the ticks were found most often in rural areas. The European blackbird is a host for an apicomplexan intestinal parasites that fall under the genus Isospora. A blackbird that has higher levels of carotenoid slows the replication rate of Isospora but does not prevent parasite from appearing.

The common cuckoo (Cuculus canorus) is a brood parasite that does not typically affect the blackbird and studies have been done to see why the blackbird is not subjected to the cuckoo parasitism. In the experiment, the blackbirds were very aggressive and were quick to remove the parasite's egg. This aggressiveness is likely the reason for low brood parasitism by the common cuckoo. (Breitbach, et al., 2012; Gregoire, et al., 2002; Grim and Honza, 2001; Lucenicova, et al., 2014)

  • Ecosystem Impact
  • disperses seeds
Commensal/Parasitic Species

Economic Importance for Humans: Positive

The European blackbird visits birdfeeders at urban parks and adds species variation for birdwatchers at theses feeders. This species also was used as a model organism in one study evaluating the effects of human disturbance on feeding patterns. (Fernandez-Juricic and Telleria, 2000)

  • Positive Impacts
  • ecotourism
  • research and education

Economic Importance for Humans: Negative

There are no negative economic impacts that the European blackbird has on humans.

Conservation Status

The European blackbird is listed as a species of “Least Concern” on IUCN Red List. It is listed as a species with “No special status” on the U.S. Migratory Bird Act, U.S. Federal List, and CITES.

The population is believed to be stable overall, but may be declining in some rural areas. The reason for this decline is agricultural changes made by farmers. Conservation efforts for the blackbird is limited due to its presumed stability and commonality. Limiting human disturbance in urban parks would aid in managing the population size in those areas. (Fernandez-Juricic and Telleria, 2000; )

Contributors

Monika Mattson (author), Radford University, Cari Mcgregor (editor), Radford University, Zeb Pike (editor), Radford University, Karen Powers (editor), Radford University, April Tingle (editor), Radford University, Jacob Vaught (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

frugivore

an animal that mainly eats fruit

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

insectivore

An animal that eats mainly insects or spiders.

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

male parental care

parental care is carried out by males

migratory

makes seasonal movements between breeding and wintering grounds

molluscivore

eats mollusks, members of Phylum Mollusca

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

urban

living in cities and large towns, landscapes dominated by human structures and activity.

visual

uses sight to communicate

References

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Breitbach, N., K. Bohning-Gaese, I. Laube, M. Schleuning. 2012. Short seed-dispersal distances and low seedling recruitment in farmland populations of bird-dispersed cherry trees. Journal of Ecology, 100/6: 1349-1358.

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