Editing Common starling (section)

== Behaviour and ecology ==
[[File:European starling (Sturnus vulgaris) in flight Lerma composite of 5 images.jpg|thumb|Composite of five images showing a starling dropping an insect then diving to try to recapture it]]
The common starling is a highly gregarious species, especially in autumn and winter. Although [[Group size measures|flock size]] is highly variable, huge, noisy flocks (murmurations) may form near roosts. These dense concentrations of birds are thought to be a defence against attacks by [[birds of prey]] such as [[peregrine falcon]]s or [[Eurasian sparrowhawk]]s.<ref name= Taylor>Taylor & Holden (2009) p. 27.</ref><ref>{{Cite journal| doi = 10.1016/j.anbehav.2008.08.034 | issn = 0003-3472| volume = 77| issue = 1 | pages = 101–107| last1 = Carere| first1 = Claudio| last2=Montanino |first2=Simona |last3=Moreschini |first3=Flavia |last4=Zoratto |first4=Francesca |last5=Chiarotti |first5=Flavia |last6=Santucci |first6=Daniela |last7=Alleva |first7=Enrico | title = Aerial flocking patterns of wintering starlings, ''Sturnus vulgaris'', under different predation risk | journal = Animal Behaviour| year = 2009| s2cid = 53257103}}</ref> Flocks form a tight [[sphere]]-like formation in flight, frequently expanding and contracting and changing shape, seemingly without any sort of leader. Each common starling changes its course and speed as a result of the movement of its closest neighbours.<ref>{{Cite journal | doi = 10.1093/beheco/arq149 | issn =1465-7279 | volume = 21 | issue = 6 | pages = 1349–1359 | last1 = Hildenbrandt | first1 = H | last2 =Carere |first2 =C |last3=Hemelrijk |first3=C K | title = Self-organized aerial displays of thousands of starlings: a model | journal = Behavioral Ecology | year = 2010| doi-access = free | arxiv = 0908.2677 }}</ref>

Very large roosts, up to 1.5&nbsp;million birds, form in city centres, woodlands and reedbeds, causing problems with their droppings. These may accumulate up to {{convert|30|cm|in|abbr=on}} deep, killing trees by their concentration of chemicals. In smaller amounts, the droppings act as a [[fertiliser]], and therefore woodland managers may try to move roosts from one area of a wood to another to benefit from the soil enhancement and avoid large toxic deposits.<ref name=currie>Currie ''et al'' (1977) leaflet 69.</ref>[[File:Sturnus vulgaris -Rotterdam, South Holland, Netherlands -flock-8.ogv|thumb|300px|thumbtime=43|alt=A large flock|A large flock in [[Rotterdam]], Netherlands|left]]

Flocks of more than a million common starlings may be observed just before sunset in spring in southwestern [[Jutland]], Denmark, over the seaward [[marshland]]s of [[Tønder]] and [[Esbjerg]] municipalities between Tønder and [[Ribe]]. They gather in March until northern Scandinavian birds leave for their breeding ranges by mid-April. Their [[swarm behaviour]] creates complex shapes silhouetted against the sky, a phenomenon known locally as ''[[Sort sol (bird flock)|sort sol]]'' ("black sun").<ref>{{cite web |url= http://epod.usra.edu/blog/2006/06/black-sun-in-denmark.html| author =Winkler, Bjarne |title= Black Sun in Denmark |work= Earth Science Picture of the Day |publisher = NASA Earth Science Division, EOS Project Science Office and the Universities Space Research Association|date= 2006-06-19 |access-date= 2013-01-10}}</ref>
Flocks of anything from five to fifty thousand common starlings form in areas of the UK just before sundown during mid-winter. These flocks are commonly called murmurations.<ref name=West>{{cite journal |last1=West |first1=Meredith J |last2=King |first2=Andrew P |year=1990 |title=Mozart's Starling |journal=American Scientist |volume=78 |issue=2 |pages=106–114 |url=http://www.indiana.edu/~aviary/Research/Mozart%27s%20Starling.pdf |bibcode=1990AmSci..78..106W |access-date=2013-01-17 |archive-date=2014-06-30 |archive-url=https://web.archive.org/web/20140630230614/http://www.indiana.edu/~aviary/Research/Mozart%27s%20Starling.pdf |url-status=dead }}</ref>

=== Feeding ===
[[File:A field at Aghagallon - geograph.org.uk - 488583.jpg|right|thumb|A flock foraging at a farm in Northern Ireland]]

The common starling is largely [[insectivorous]] and feeds on both pest and other [[arthropod]]s. The food range includes [[spider]]s, [[Tipuloidea|crane flies]], [[moth]]s, [[Mayfly|mayflies]], [[Dragonfly|dragonflies]], [[damselfly|damsel flies]], [[grasshopper]]s, [[earwig]]s, [[lacewing]]s, [[Caddisfly|caddisflies]], [[Fly|flies]], [[beetle]]s, [[Sawfly|sawflies]], [[bee]]s, [[wasp]]s and [[ant]]s. Prey are consumed in both adult and larvae stages of development, and common starlings will also feed on [[earthworm]]s, [[snail]]s, small [[amphibian]]s and [[lizard]]s.<ref name="Adeney"/><ref>{{cite journal |last1=Shimbov |first1=Mario I. |last2=Allain |first2=Steven J. R. |date=2022 |title=Smooth newt ''Lissotriton vulgaris'' preyed upon by European starling ''Sturnus vulgaris'' |journal= Herpetological Bulletin |issue=161 |pages=46 |doi=10.33256/hb161.46 |s2cid=252034217 |url=https://www.thebhs.org/publications/the-herpetological-bulletin/issue-number-161-autumn-2022/3536-14-smooth-newt-i-lissotriton-vulgaris-i-preyed-upon-by-european-starling-i-sturnus-vulgaris-i|doi-access=free }}</ref> While the consumption of [[invertebrates]] is necessary for successful breeding, common starlings are [[omnivorous]] and can also eat [[Cereal|grains]], [[seeds]], [[fruits]], [[nectar]] and [[food waste]] if the opportunity arises.<ref name=H1907/><ref name =emu>{{cite journal | last=Thomas | first= H F | year=1957 | title= The Starling in the Sunraysia District, Victoria. Part I| journal= Emu | volume= 57 | issue = 1 | pages= 31–48 | doi=10.1071/MU957031 }}</ref><ref name=pestnote>{{cite web |author1=Kirkpatrick, Win |author2=Woolnough, Andrew P |year=2007 |title=Common starling |work=Pestnote |publisher=Department of Agriculture and Food Australia |url=http://www.agric.wa.gov.au/objtwr/imported_assets/content/pw/vp/bird/common_starling.pdf |access-date=2013-01-19 |archive-url=https://web.archive.org/web/20160323005918/https://www.agric.wa.gov.au/objtwr/imported_assets/content/pw/vp/bird/common_starling.pdf |archive-date=2016-03-23 |url-status=dead }}</ref> The Sturnidae differ from most birds in that they cannot easily metabolise foods containing high levels of [[sucrose]], although they can cope with other fruits such as grapes and cherries.<ref name= bvaawf/> The isolated Azores subspecies of the common starling eats the eggs of the endangered [[roseate tern]]. Measures are being introduced to reduce common starling populations by culling before the terns return to their breeding colonies in spring.<ref name=neves>{{cite journal | last1= Neves | first1= Verónica C | last2= Griffiths | first2= Kate | last3= Savory | first3= Fiona R | last4= Furness | first4= Robert W | last5= Mable | first5= Barbara K | year= 2009 | title= Are European starlings breeding in the Azores archipelago genetically distinct from birds breeding in mainland Europe? | journal= European Journal of Wildlife Research | volume= 56 | issue= 1 | pages= 95–100 | doi= 10.1007/s10344-009-0316-x | s2cid= 6618717 | url= https://hal.archives-ouvertes.fr/hal-00535248/file/10344_2009_316_ReferencePDF.pdf }}</ref>

[[File:Feeding the young starlings.ogv|thumbtime=40|thumb|left|An adult foraging and finding food for young chicks]]

There are several methods by which common starlings obtain their food, but, for the most part, they forage close to the ground, taking insects from the surface or just underneath. Generally, common starlings prefer foraging amongst short-cropped grasses and eat with grazing animals or perch on their backs,<ref name=pestnote/> where they will also feed on the mammal's external parasites.<ref name=feare183/> Large flocks may engage in a practice known as "roller-feeding", where the birds at the back of the flock continually fly to the front where the feeding opportunities are best.<ref name=H1907/> The larger the flock, the nearer individuals are to one another while foraging. Flocks often feed in one place for some time, and return to previous successfully foraged sites.<ref name=H1907/>

There are three types of foraging behaviours observed in the common starling. "Probing" involves the bird plunging its beak into the ground randomly and repetitively until an insect has been found, and is often accompanied by bill gaping where the bird opens its beak in the soil to enlarge a hole. This behaviour, first described by [[Konrad Lorenz]] and given the German term ''zirkeln'',<ref>{{cite journal|title=Foraging decisions in starlings (''Sturnus vulgaris'' L.)|last=Tinbergen|first=J. M.|year=1981|journal=Ardea|volume=69|pages=1–67|doi=10.5253/arde.v69.p1|s2cid=88425778|url=https://pure.rug.nl/ws/files/135597596/a69_001_067.pdf}}</ref> is also used to create and widen holes in plastic garbage bags. It takes time for young common starlings to perfect this technique, and because of this the diet of young birds will often contain fewer insects.<ref name=hbw/> "[[Hawking (birds)|Hawking]]" is the capture of flying insects directly from the air, and "lunging" is the less common technique of striking forward to catch a moving [[invertebrate]] on the ground. Earthworms are caught by pulling from soil.<ref name=H1907/> Common starlings that have periods without access to food, or have a reduction in the hours of light available for feeding, compensate by increasing their body mass by the deposition of fat.<ref name= witter>{{cite journal | last1= Witter | first1= M S| last2= Swaddle | first2= J P | last3= Cuthill | first3= I C | year=1995 | title= Periodic food availability and strategic regulation of body mass in the European starling, ''Sturnus vulgaris'' | journal= Functional Ecology | volume= 9 | issue = 4 | pages= 568–574 | jstor= 2390146 | doi= 10.2307/2390146 | bibcode= 1995FuEco...9..568W}}</ref>

=== Nesting ===
[[File:Juvenile European starling (10739).jpg|thumb|right|A parent feeding a chick]]
Unpaired males find a suitable cavity and begin to build nests in order to attract single females, often decorating the nest with ornaments such as flowers and fresh green material, which the female later disassembles upon accepting him as a mate.<ref name=H1923/><ref name=Brouwer>{{cite journal | last1= Brouwer | first1= Lyanne | last2= Komdeur | first2= Jan | year= 2004 | title= Green nesting material has a function in mate attraction in the European starling | journal= Animal Behaviour | volume= 67 | issue= 3 | pages= 539–548 | doi= 10.1016/j.anbehav.2003.07.005 | hdl= 11370/18688a82-a350-4483-9e8c-977573cc5c85 | s2cid= 53166185 | url= http://www.myscience.eu/lyanne/pdfs/brouweretal04.pdf | access-date= 2013-03-03 | archive-url= https://web.archive.org/web/20160304001027/http://www.myscience.eu/lyanne/pdfs/Brouweretal04.pdf | archive-date= 2016-03-04 | url-status= dead }}</ref> The amount of green material is not important, as long as some is present, but the presence of [[herbs]] in the decorative material appears to be significant in attracting a mate. The scent of plants such as [[Achillea millefolium|yarrow]] acts as an [[olfaction|olfactory]] attractant to females.<ref name=Brouwer/><ref name=Gwinner>{{cite journal | last1= Gwinner| first1=Helga | last2= Berger | first2= Silke| year= 2008| title=Starling males select green nest material by olfaction using experience-independent and experience-dependent cues | journal= Animal Behaviour | volume= 75 | issue = 3 | pages= 971–976 | doi =10.1016/j.anbehav.2007.08.008 | s2cid=53150932 }}</ref>

The males sing throughout much of the construction and even more so when a female approaches his nest. Following [[Copulation (zoology)|copulation]], the male and female continue to build the nest. Nests may be in any type of hole, common locations include inside hollowed trees, buildings, tree stumps and man-made nest-boxes.<ref name=H1923/> ''S. v. zetlandicus'' typically breeds in crevices and holes in cliffs, a habitat only rarely used by the nominate form.<ref name= michael>{{cite journal | last= Michael | first= Edwin D | year=1971 | title= Starlings nesting in rocky cliffs | journal= Bird-Banding | volume= 42 | issue = 2 | page= 123 |jstor =4511747 | doi= 10.2307/4511747 }}</ref> Nests are typically made out of straw, dry grass and twigs with an inner lining made up of feathers, wool and soft leaves. Construction usually takes four or five days and may continue through incubation.<ref name=H1923/>

Common starlings are both [[Monogamy in animals|monogamous]] and [[Animal sexual behaviour#Polygamy|polygamous]]; although broods are generally brought up by one male and one female, occasionally the pair may have an extra helper. Pairs may be part of a colony, in which case several other nests may occupy the same or nearby trees.<ref name=H1923/> Males may mate with a second female while the first is still on the nest. The reproductive success of the bird is poorer in the second nest than it is in the primary nest and is better when the male remains monogamous.<ref name= sandell>{{cite journal | last1= Sandell | first1= Maria I | last2= Smith | first2= Henrik G | last3= Bruun | first3= Måns | year=1996 | title= Paternal care in the European Starling, ''Sturnus vulgaris'': nestling provisioning | journal= Behavioral Ecology and Sociobiology | volume= 39 | issue = 5 | pages= 301–309 | doi =10.1007/s002650050293| bibcode= 1996BEcoS..39..301S | s2cid= 19891369 }}</ref>

=== Breeding ===
[[File:Starling eggs.jpeg|right|thumb|Five eggs in a nest]]Breeding takes place during the spring and summer. Following copulation, the female lays eggs on a daily basis over a period of several days. If an egg is lost during this time, she will lay another to replace it. There are normally four or five eggs that are [[ovoid]] in shape and pale blue or occasionally white, and they commonly have a glossy appearance.<ref name=H1923/> The colour of the eggs seems to have evolved through the relatively good visibility of blue at low light levels.<ref name= weg>{{cite journal| last= Węgrzyn | first= E |author2=Leniowski, K|author3=Rykowska, I|author4=Wasiak, W | year=2011 | title= Is UV and blue-green egg colouration a signal in cavity-nesting birds? | journal= Ethology Ecology and Evolution | volume=23 | pages= 121–131 | doi = 10.1080/03949370.2011.554882| issue= 2 | bibcode= 2011EtEcE..23..121W | s2cid= 85353700 }}</ref> The egg size is {{convert|26.5|–|34.5|mm|in|abbr=on}} in length and {{convert|20.0|–|22.5|mm|in|abbr=on}} in maximum diameter.<ref name=feare183/>[[File:Sturnus vulgaris MWNH 2328.JPG|thumb|Eggs, Collection [[Museum Wiesbaden]], Germany|left]][[Avian incubation|Incubation]] lasts thirteen days, although the last egg laid may take 24&nbsp;hours longer than the first to hatch. Both parents share the responsibility of brooding the eggs, but the female spends more time incubating them than does the male, and is the only parent to do so at night when the male returns to the communal roost. A pair can raise up to three broods per year, frequently reusing and relining the same nest,<ref name="H1923"/> although two broods is typical,<ref name =feare183/> or just one north of 48°N.<ref name=linz/>

The young are born blind and naked. They develop light fluffy down within seven days of hatching and can see within nine days.<ref name="H1923"/> As with other passerines, the nest is kept clean and the chicks' [[fecal sac|faecal sacs]] are removed by the adults.<ref name= wright>{{cite journal| last= Wright | first= Jonathan |author2=Cuthill, Innes | year= 1989| title= Manipulation of sex differences in parental care | journal= Behavioral Ecology and Sociobiology| volume= 25 | issue = 3 | pages= 171–181 | doi =10.1007/BF00302916| bibcode= 1989BEcoS..25..171W | s2cid= 10779154 }}</ref> Once the chicks are able to regulate their body temperature, about six days after hatching,<ref name=oulu>Marjoniemi (2001) p. 19.</ref> the adults largely cease removing droppings from the nest. Prior to that, the fouling would wet both the chicks' plumage and the nest material, thereby reducing their effectiveness as insulation and increasing the risk of chilling the hatchlings.<ref name= burton>Burton (1985) p. 187.</ref> [[Nestlings]] remain in the nest for three weeks, where they are fed continuously by both parents. [[Fledgling (birds)|Fledgling]]s continue to be fed by their parents for another one or two weeks. Within two months, most juveniles will have moulted and gained their first basic plumage. They acquire their adult plumage the following year.<ref name="H1923"/>[[File:Starling chicks Clarinbridge.jpg|thumb|alt=Chicks waiting to be fed|Chicks waiting to be fed at the entrance of their nest made in a gap in a wall in [[Galway]], Ireland]]

[[Intraspecific hybrid|Intraspecific]] [[brood parasites]] are common in common starling nests. Female "floaters" (unpaired females during the breeding season) present in colonies often lay eggs in another pair's nest.<ref name=Sandell>{{cite journal | last1= Sandell| first1= M I| last2=Diemer| first2= Michael | year=1999 | title=Intraspecific brood parasitism: a strategy for floating females in the European starling | journal= Animal Behaviour | volume= 57 | issue = 1 | pages= 197–202 | pmid = 10053087 | doi=10.1006/anbe.1998.0936 | s2cid= 25788559| doi-access= free }}</ref> Fledglings have also been reported to invade their own or neighbouring nests and evict a new brood.<ref name=H1923/> Common starling nests have a 48% to 79% rate of successful fledging, although only 20% of nestlings survive to breeding age; the adult survival rate is closer to 60%. The average life span is about 2–3 years,<ref name= linz/> with a longevity record of 22 years 11 months.<ref name = euring>{{cite web | title= European Longevity Records | url= http://www.euring.org/data_and_codes/longevity-voous.htm| publisher= Euring| access-date =2013-01-20 }}</ref>