Eurasian blue tit

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Eurasian blue tit
Blue Tit (Cyanistes caeruleus) portrait.jpg
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Paridae
Genus: Cyanistes
Species: C. caeruleus
Binomial name
Cyanistes caeruleus
(Linnaeus, 1758)
CyanistesCaeruleusDistribution.png
Eurasian blue tit range dark green, African blue tit range light green
Synonyms

Parus caeruleus Linnaeus, 1758

The Eurasian blue tit (Cyanistes caeruleus[2] or Parus caeruleus[3]) is a small passerine bird in the tit family Paridae. The bird is easily recognisable by its blue and yellow plumage, but various authorities dispute their scientific classification.

Eurasian blue tits, usually resident and non-migratory birds, are widespread and a common resident breeder throughout temperate and subarctic Europe and western Asia in deciduous or mixed woodlands with a high proportion of oak. They usually nest in tree holes, although they easily adapt to nest boxes where necessary. Their main rival for nests and in the search for food is the larger great tit.

The Eurasian blue tit prefers insects and spiders for its diet. Outside the breeding season, they also eat seeds and other vegetable-based foods. The birds are famed for their skill, as they can cling to the outermost branches and hang upside down when looking for food.

Taxonomy[edit]

This species was first described by Linnaeus in his Systema naturae in 1758 as Parus caeruleus.[4]

Most authorities retain Cyanistes as a subgenus of Parus, but the British Ornithologists' Union treats Cyanistes as a distinct genus. This is supported by mtDNA cytochrome b sequence analysis which suggests that Cyanistes is not only distinct, but not close to other tits.[5] The African blue tit was formerly considered conspecific.

Subspecies[edit]

There are currently at least nine recognised subspecies:[6]

  • C. c. caeruleus (Linnaeus, 1758), the nominate subspecies, occurring in Continental Europe to northern Spain, Sicily, northern Turkey and northern Urals
  • C. c. obscurus (Pražák, 1894), Ireland, Britain and Channel Islands[7]
  • C. c. ogilastrae (Hartert, 1905), Portugal, southern Spain, Corsica and Sardinia
  • C. c. balearicus (von Jordans, 1913), Majorca Island (Balearic Islands)
  • C. c. calamensis (Parrot, 1908), southern Greece, Pelopónnisos, Cyclades, Crete and Rhodes
  • C. c. orientalis (Zarudny & Loudon, 1905), southern European Russia (Volga River to central and southern Urals)
  • C. c. satunini (Zarudny, 1908), Crimean Peninsula, Caucasus, Transcaucasia and northwestern Iran to eastern Turkey
  • C. c. raddei (Zarudny, 1908), northern Iran
  • C. c. persicus (Blanford, 1873), Zagros Mountains


Hybrids[edit]

Pleske's tit (Cyanistes pleskei) is a common hybrid between this species and the azure tit in western Russia. The cap is usually darker than the azure tit, and the tail is paler than the Eurasian blue tit.[8]

Description[edit]

The Eurasian blue tit is usually 12 centimetres (4.7 in) long with a wingspan of 18 centimetres (7.1 in) for all genders, and weighs about 11 grams (0.39 oz).[9]

Eurasian Blue Tit in close up

A typical Eurasian blue tit has an azure blue crown and dark blue line passing through the eye, and encircling the white cheeks to the chin, giving the bird a very distinctive appearance. The forehead and a bar on the wing are white. The nape, wings and tail are blue and the back is yellowish green. The underparts is mostly sulphur-yellow with a dark line down the abdomen - the yellowness is indicative of the number of yellowy-green caterpillars eaten, due to high levels of carotene pigments in the diet.[10] The bill is black, the legs bluish grey, and the irides dark brown. The sexes are similar, but under ultraviolet light, males have a brighter blue crown.[11] Young blue tits are noticeably more yellow.

Distribution and habitat[edit]

There are currently around 20–44 million pairs in Europe.[12]

The Eurasian blue tit and the related hybrids are considered native species in areas of the European continent with a mainly temperate or Mediterranean climate, and in parts of the Middle East. These areas include the United Kingdom and most of the European Union and EFTA (except Malta, where they are considered vagrant, and Iceland, where they are absent), plus: Albania, Algeria, Andorra, Armenia, Azerbaijan, Belarus, Bosnia and Herzegovina, Georgia, Iran, Iraq, Jordan, Kazakhstan, Lebanon, Libya, the Republic of Macedonia, Moldova, Montenegro, Morocco, Russia, San Marino, Serbia, Syria, Tunisia, Turkey, Vatican City and Ukraine.[13]

Behaviour and ecology[edit]

Juvenile in Pimlico, London

Eurasian blue and great tits form mixed winter flocks, and the former are perhaps the better gymnasts in the slender twigs. A Eurasian blue tit will often ascend a trunk in short jerky hops, imitating a treecreeper. As a rule the bird roosts in ivy or evergreens, but in harsh winters will nest wherever there is a suitable small hole, be it in a tree or nesting box. They are very agile and can hang from almost anywhere.

This is a common and popular European garden bird, due to its perky acrobatic performances when feeding on nuts or suet. It swings beneath the holder, calling "tee, tee, tee" or a scolding "churr".

Breeding[edit]

Feeding the young at a nest box in England
Eggs of Cyanistes caeruleus ultramarinus MHNT
Young inside a nestbox in Nittedal, Norway

The Eurasian blue tit will nest in any suitable hole in a tree, wall, or stump, or an artificial nest box, often competing with house sparrows or great tits for the site. Few birds more readily accept the shelter of a nesting box; the same hole is returned to year after year, and when one pair dies another takes possession. It is estimated by the RSPB that there are 3,535,000 breeding pairs in the UK.[12]

The bird is a close sitter, hissing and biting at an intruding finger. In the South West of England such behaviour has earned the Eurasian blue tit the colloquial nickname "Little Billy Biter".[by whom?] When protecting its eggs it raises its crest, but this is a sign of excitement rather than anger, for it is also elevated during nuptial display. The nesting material is usually moss, wool, hair and feathers, and the eggs are laid in April or May. The number in the clutch is often very large, but seven or eight are normal, and bigger clutches are usually laid by two or even more hens. It is not unusual for a single bird to feed the chicks in the nest at a rate of one feed every ninety (90) seconds during the height of the breeding season. In winter they form flocks with other tit species.

Diet[edit]

Eating peanuts from a garden bird feeder in England

The Eurasian blue tit is a valuable destroyer of pests, though it has not an entirely clean sheet as a beneficial species. It is fond of young buds of various trees, and may pull them to bits in the hope of finding insects. No species, however, destroys more coccids and aphids, the worst foes of many plants. It takes leaf miner grubs and green tortrix moths (Tortricidae). Seeds are eaten, as with all this family.

Voice[edit]

Eurasian blue tits use songs and calls throughout the year.[14] Songs are mostly used in late winter and spring to defend the territory or to attract mates. Calls are used for multiple reasons.[15] Communication with other Eurasian blue tits is the most important motivation for the use of calls. They inform one another on their location in trees by means of contact-calls. They use alarm-calls to warn others (including birds of other species such as the great tit, the European robin or the treecreeper) about the presence of predators in the neighbourhood. Scolding for example is used when a ground predator (e.g. fox, cat or dog), a low flying predator or a perched owl are noticed.[16] Sometimes this is followed by mobbing behaviour in which birds gather together in flocks to counter a predator. The alarm-whistle warns other birds about the proximity of a Eurasian sparrowhawk, a northern goshawk, a common buzzard or other flying predators that form a potential danger in the air. A series of high-pitched 'zeedling' notes are given by both partners before and during copulation.[17] The begging-call is used by juveniles to beg for food from parents.

Learning[edit]

Eurasian blue tits are able to culturally transmit learning to other tit species. An example of this, dating from the 1920s, is the ability to open milk bottles with foil tops, to get at the cream underneath.[18] Such behaviour has been suppressed recently by the gradual change of human dietary habits (low-fat or skimmed milk instead of full-fat), and the way of getting them (from a supermarket, instead of the milkman).[19]

Predators and natural threats[edit]

The small size of the Eurasian blue tit makes it vulnerable to prey by larger birds such as jays who catch the vulnerable fledglings when leaving the nest. The most important predator is probably the sparrowhawk, closely followed by the domestic cat. Nests may be robbed by mammals such as weasels and red squirrels and grey squirrels in the UK.

The successful breeding of chicks is dependent on sufficient supply of green caterpillars as well as satisfactory weather. Breeding seasons may be affected badly if the weather is cold and wet between May and July,[20] particularly if this coincides with the emergence of the caterpillars on which the nestlings are fed.

Parasites and lifespan[edit]

Eurasian blue tits are known to be host to feather mites, and rarely lice and flat flies. In Europe the only feather mite species known to live on the blue tit host is Proctophyllodes stylifer. P. stylifer however seems to be of no concern to the bird as, until now, it is only known to feed on dead feather tissue. P. stylifer lives all its developmental stages, i.e. egg, larva, protonymph, tritonymph and adult, within the plumage of the same host. The usual sites where P. stylifer is encountered are the remiges and the rectrices of the bird where they can be found tandemly positioned between the barbs of the rachis.[21]

The Eurasian blue tit has an average life expectancy of one-and-a-half to three years.[9][22] The longest recorded lifespans by country for the species are: 11 years 7 months in the Czech Republic,[23] and 9 years 9 months 2 days in the United Kingdom.[24]

Status and conservation[edit]

The Eurasian blue tit is classified as a Least Concern species on the IUCN Red List (version 3.1),[1] and as a Green Status species, since 1996, by the Royal Society for the Protection of Birds in the United Kingdom.[9][12]

Relationship with humans[edit]

The Eurasian blue tit has appeared in many stamps and ornaments. For example, the 2010 Birds of Britain series is the most recent appearance of the bird on a British stamp.[25]

Citations[edit]

  1. ^ a b BirdLife International (2012). "Parus caeruleus". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 1 May 2014. 
  2. ^ Wright, Gill, Frank and Minturn (2006). Birds of the World: Recommended English Names (1 ed.). Princeton University Press. pp. ix + 259. ISBN 0-691-12827-8. 
  3. ^ Howard, Richard; Moore, Alick (2003). Edward Dickinson, ed. The Howard and Moore Complete Checklist of the Birds of the World (3rd ed.). Christopher Helm. ISBN 0-7136-6536-X. 
  4. ^ Linnaeus, C (1758). Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. (in Latin). Holmiae. (Laurentii Salvii). p. 190. "P. remigibus caerulescentibus : primoribus margine exteriore albis, fronte alba, vertice caeruleo." 
  5. ^ Gill, Frank B.; Beth Slikas and Frederick H. Sheldon (2005). "Phylogeny of titmice (Paridae): II. Species relationships based on sequences of the mitochondrial cytochrome-b gene". Auk 122 (1): 121–143. doi:10.1642/0004-8038(2005)122[0121:POTPIS]2.0.CO;2. 
  6. ^ Clements, James (2011). The Clements Checklist of Birds of the World (6th ed.). Cornell University Press. ISBN 0-7136-8695-2. 
  7. ^ Mlíkovský, Jiří (26 August 2011). "Nomenclatural and taxonomic status of bird taxa (Aves) described by an ornithological swindler, Josef Prokop Pražák (1870–1904)". Zootaxa (3005): 45–68. 
  8. ^ Harrap, Simon; Quinn, David (Illus.) (2010). Tits, Nuthatches and Treecreepers. A&C Black. p. 94. ISBN 978-1-4081-3458-0. 
  9. ^ a b c "Blue Tit (Cyanistes caeruleus)". British Trust for Ornithology. 8 December 2010. Retrieved 23 August 2011. 
  10. ^ "Blue tit, Nature Wildlife". BBC. 23 August 2011. Retrieved 23 August 2011. 
  11. ^ "Blue tits are ultraviolet tits". Royal Society. 22 March 1998. Retrieved 17 March 2012. 
  12. ^ a b c "Blue Tit". RSPB. 23 August 2011. Retrieved 23 August 2011. 
  13. ^ "Parus caeruleus (Blue Tit) - Map". IUCN Red List of Threatened Species. International Union for Conservation of Nature. Retrieved 1 May 2014. 
  14. ^ Cramp S, Perrins CMP et al(1993). Handbook of the Birds of Europe the Middle East and North Africa - The Birds of the Western Palearctic Volume VII. Oxford University Press, Oxford, New York 1993
  15. ^ Bijnens L and Dhondt AA (1984). Vocalizations in a Belgian Blue Tit Parus c. caeruleus population. Gerfault 74, 243-69
  16. ^ Klump GM and Curio E (1983). Reactions of Eurasian Blue Tits Parus caeruleus to Hawk Models of Different Sizes. Bird Behavior 4, 78-81
  17. ^ Hinde, RA (1952). The behaviour of the Great Tit (Parus Major) and some other related species. Behaviour (Suppl.) II: 1-201.
  18. ^ Sasvári, Lajos (August 1979). "Observational learning in great, blue and marsh tits". Animal Behaviour 27 (3): 767–771. doi:10.1016/0003-3472(79)90012-5. 
  19. ^ McCarthy, Michael (31 December 2003). "Blue tits lose their bottle as milk thieves". The Independent. Retrieved 22 August 2011. 
  20. ^ Derbyshire, David (5 November 2007). "Disappearing blue tits pay the price of soggy summer". The Daily Mail (Associated Newspapers). Retrieved 23 August 2011. 
  21. ^ Braasch, Norman, L (1966). The feather mite genus 'Proctophyllodes (Sarcoptiformes: Proctophyllodidae) (1 ed.). University of Nebraska. pp. 1–351. 
  22. ^ "Life Expectancy". British Garden Birds. David Gains. Retrieved 24 January 2007. 
  23. ^ "European Longevity Records". European Union for Bird Ringing (EURING). 26 November 2010. Retrieved 23 August 2011. 
  24. ^ "Longevity records for Britain & Ireland in 2009". British Trust for Ornithology. 9 December 2010. Retrieved 23 August 2011. 
  25. ^ Stephens, Kate (2010), Birds of Britain I - A Presentation Pack, Royal Mail 

Further reading[edit]

  • Javier Blasco-Zumeta; Gerd-Michael Heinze (9 May 2011). "393 - Blue Tit". Laboratorio Virtual Ibercaja. Retrieved 31 March 2013. 

External links[edit]