Dunnock
| Dunnock | |
|---|---|
 |
|
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Passeriformes |
| Family: | Prunellidae |
| Genus: | Prunella |
| Species: | P. modularis |
| Binomial name | |
| Prunella modularis (Linnaeus, 1758) |
|
The Dunnock (Prunella modularis) is a small passerine bird found throughout temperate Europe and into Asia. It is by far the most widespread member of the accentor family, which otherwise consists of mountain species. It is sometimes called the Hedge Accentor, Hedge Sparrow or Hedge Warbler. The name "dunnock" comes from the Ancient British *dunnākos, meaning "little brown one".
It is a resident in the milder west and south of its range, but as an insectivore, must migrate south from the colder parts of its range. It is a bird of woodland, shrub and gardens. It builds a neat nest low in a bush or conifer, laying 3-5 unspotted blue eggs.
It is a host of the Common Cuckoo. It is likely that this association is recent, since other Cuckoo hosts have learned to discriminate between eggs, and the Cuckoo has consequently evolved eggs that match those of its host. In the case of the Dunnock, there is no resemblance, yet the Cuckoo eggs are accepted.
This is a Robin-sized bird, 13.5–14 cm in length, fairly drab in appearance, and somewhat resembling a small House Sparrow with its streaked back and general shape. It is also brownish underneath, and has a fine pointed bill. Adults have a grey head. The sexes are similarly coloured. They were introduced to New Zealand between 1867 and 1882 and now breed throughout the country including on the Chatham, Antipodes, Auckland and Campbell islands.[2]
This species makes up for its drab appearance with its breeding behaviour. Females are often polyandrous, breeding with two males at once, and thus giving rise to sperm competition. Males compete for mating access to the female, but DNA fingerprinting has shown that chicks within broods often have different fathers, depending on their success at monopolising access to the fertile female. Males try to ensure their paternity during courtship by pecking at the cloaca of the female to stimulate her to eject the sperm of other males with whom the female has recently mated.[3] Dunnocks take just one-tenth of a second to copulate, and have sex more than 100 times a day.[4] Males provide parental care in proportion to their mating success, so it is not uncommon to see two males and a female provisioning nestlings at one nest. Polyandry is rare in birds, with only about 2% of species showing such a mating system; the majority are monogamous, where one male and one female breed together.[citation needed]
The main call is a shrill, persistent "tseep" and a high trilling note,[5] which often betray the bird's otherwise inconspicuous presence. The song is rapid, thin and tinkling, a sweet warble which can be confused with the Wren but is shorter and weaker.[5] The Wren's song incorporates repeated trill sounds but the Dunnock's does not.[citation needed] While the Dunnock's bubbling song is very pleasant, it has been described as being similar to a squeaky trolley wheel.[citation needed]
Contents |
Mating Systems [edit]
Multiple mating combinations exist within dunnock populations, including monogamy (strict pairs), polyandry (two or three males with one female), polygyny (one male with two females), and polygynandry (two or three males with two to four females). Male dunnocks have the largest amount of reproductive success with polygyny and the least in a cooperative polyandrous relationship. Contrarily, the opposite holds true for female dunnocks, who have more success with cooperative polyandry than with polygyny. As a result, these opposite spectrums of reproductive success leads to observed conflicts in the behaviors of female versus male dunnocks as each aim to pursue their interests in a competing range of mating systems. The resulting variable mating system is therefore reflective of the different possible outcomes stemming from sexual conflict between males and females. In cooperative polyandry, females have a gain at the expense of males, while monogamy and polygynandry are mating systems where neither sex is able to have an advantage at the expense of the other. [6]
In terms of territories, female ranges are always exclusive. If two or three males shared one or more females, the males’ ranges overlapped and they would cooperate in order to defend the territory. Among the males is a dominance hierarchy: older birds tend to be the alpha male and first year birds are usually the beta males. Studies have not found cases of close male relatives being involved in any mating combinations. It is possible that the different mating combinations form a continuum as a result of a male’s ability to monopolize his access to females, which can vary from unpaired, to shared access to a female, to sole access to one female, to shared access to multiple females, and lastly, to sole access to multiple females. The male’s ability to control his access to females generally depends on female range size, which is affected by the distribution of food. When there are dense patches of resources, female ranges tend to be small, so the males more easily monopolized them. This led to mating combinations with high male mating success, such as polygyny and polygynandry. If food patches are scarcer, female rangers were larger and more difficult for a single male to monopolize, leading to mating combinations that have lower male mating success (polyandry). In a study, extra food was provided to certain territories, causing female ranges to become smaller. In turn, the mating system shifted towards greater male mating success, such as from polyandry to monogamy and polygynandry. [7]
In regard to parental care and mating behavior, a study found that males tend to not discriminate between their own young and those of another male in polyandrous or polygynandrous systems. However, they increase their own reproductive success through feeding the offspring in relation to their own access to the female throughout the mating period, which is generally a good predictor of paternity. [8]
Gallery [edit]
-
-
Adult in winter
-
-
Female, March, Isle of Wight
-
Male, March, Isle of Wight
References [edit]
- ^ BirdLife International (2012). "Prunella modularis". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 16 July 2012.
- ^ Heather, Barrie; Rogertson, Hugh (2005). The Field Guide to the Birds of New Zealand (Revised ed.). Viking Press.
- ^ Davies, N. B. (March 1983). "Polyandry, cloaca-pecking and sperm competition in dunnocks". Nature (Nature Publishing Group) 302 (5906): 334–336. doi:10.1038/302334a0.
- ^ Birkhead, Tim (2012). Bird Sense.
- ^ a b Peterson, Roger; Mountfort, Guy; Hollom, P.A.D. (1954). A Field Guide to the Birds of Britain and Europe. London: Collins.
- ^ Davies, N. B., Houston, A. I. (1986). Reproductive success of dunnocks, Prunella modularis, in a variable mating system. Journal of Animal Ecology.
- ^ Davies, N. B., Lundberg, A. (1984). Food distribution and a variable mating system in the dunnock, Prunella modularis. Journal of Animal Ecology.
- ^ Burke, T., Davies, N. B., Bruford, M. W., Hatchwell, B. J. (1989). Parental care and mating behavior of polyandrous dunnocks Prunella modularis related to paternity by DNA fingerprinting. Letters to Ecology.
- Blasco-Zumeta, Javier. "Dunnock". Laboratorio Virtual Ibercaja (IberCaja Obra Social) (324): 1–4.
- Davies, N.B. (1954). Dunnock Behaviour and Social Evolution. Oxford: Oxford University Press.
