View source for Budgerigar

{{Short description|Small, long-tailed, seed-eating parakeet}}{{Use Australian English|date=July 2013}}
{{Use dmy dates|date=February 2022}}
{{Speciesbox
| fossil_range = {{fossil range|Pliocene|Holocene|ps=<ref name=boles>{{cite journal |last1=Boles |first1=Walter E. |title=A budgerigar ''Melopsittacus undulatus'' from the Pliocene of Riversleigh, North-western Queensland |journal=Emu|date=1998 |volume=98 |issue=1 |pages=32–35 |doi=10.1071/MU98004|bibcode=1998EmuAO..98...32B }}</ref>}}
| image = Budgerigar-male-strzelecki-qld.jpg
| image_caption = Blue [[Beak#Cere|cere]] indicates male
| image2 = Budgerigar-strzelecki-qld.jpg
| image2_caption = Flaking brown [[Beak#Cere|cere]] indicates female in breeding condition
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name=IUCN>{{cite iucn|author=BirdLife International | author-link=BirdLife International |year=2018 |title=''Melopsittacus undulatus'' |page=e.T22685223A132056957 |doi=10.2305/IUCN.UK.2018-2.RLTS.T22685223A132056957.en}}</ref>
| display_parents = 3
| genus = Melopsittacus
| parent_authority = [[John Gould|Gould]], 1840
| species = undulatus
| authority = ([[George Shaw (biologist)|Shaw]], 1805)
| range_map = Budgerigar_range_map.png
| range_map_caption = The range of the Budgerigar <br/> Native range: green <br/> Introduced range: light green
}}

The '''budgerigar''' ({{IPAc-en|ˈ|b|ʌ|dʒ|ər|ɪ|ɡ|ɑːr|,_|-|ə|r|iː|-}} {{respell|BUJ|ər|ih|gar|,_|-|ə|ree|-}};<ref name=":0">{{cite Dictionary.com |budgerigar |access-date=10 September 2021}} {{Cite web |url=https://www.dictionary.com/browse/budgerigar |title=Budgerigar Definition & Meaning &#124; Dictionary.com |access-date=7 August 2021 |archive-date=7 August 2021 |archive-url=https://web.archive.org/web/20210807131931/https://www.dictionary.com/browse/budgerigar |url-status=live }}</ref> '''''Melopsittacus undulatus'''''), also known as the '''common [[parakeet]]''', '''shell parakeet''' or '''budgie''' ({{IPAc-en|ˈ|b|ʌ|dʒ|i}} {{Respell|BUJ|ee}}),<ref name=":0" /><ref>{{Cite encyclopedia|title=budgie|encyclopedia=Dictionary.com Unabridged|url=https://www.dictionary.com/browse/budgie|access-date=10 September 2021|archive-date=9 September 2021|archive-url=https://web.archive.org/web/20210909230743/https://www.dictionary.com/browse/budgie|url-status=live}}</ref> is a small, long-tailed, seed-eating [[parrot]] native to [[Australia]].  Naturally the species is green and yellow with black, scalloped markings on the nape, back, and wings.<ref name=":2">{{Cite web|title=Budgerigar|url=https://www.birdlife.org.au/bird-profile/budgerigar|url-status=live|access-date=9 September 2021|website=Birdlife Australia|language=en|archive-url=https://web.archive.org/web/20200603111437/http://birdlife.org.au/bird-profile/budgerigar |archive-date=3 June 2020 }}</ref> Budgies are bred in captivity with colouring of blues, whites, yellows, greys, and even with small [[Crest (feathers)|crests]].<ref name=":2" /><ref name=":3">{{Cite web|last=|first=|date=10 December 2020|title=Budgerigar|url=http://australian.museum/learn/animals/birds/budgerigar/|url-status=live|access-date=9 September 2021|website=The Australian Museum|language=en|archive-url=https://web.archive.org/web/20200724173305/https://australian.museum/learn/animals/birds/budgerigar/ |archive-date=24 July 2020 }}</ref> Juveniles and chicks are [[Sexual dimorphism|monomorphic]] (the sexes are visually indistinguishable), while adults are told apart by their [[Beak#Cere|cere]] colouring and their behaviour.

The species is [[Monotypic taxon|monotypic]], meaning it is the only member of the genus '''''Melopsittacus''''', which is the only genus in the ''' Melopsittacini''' tribe.  
The budgerigar is closely related to [[lories and lorikeets|lories]] and the [[fig parrot]]s.<ref name=wright>{{cite journal|last=Wright|first=TF |author2=Schirtzinger EE |author3=Matsumoto T |author4=Eberhard JR |author5=Graves GR |author6=Sanchez JJ |author7=Capelli S |author8=Mueller H |author9=Scharpegge J |author10=Chambers GK |author11=Fleischer RC|year=2008|title=A Multilocus Molecular Phylogeny of the Parrots (Psittaciformes): Support for a Gondwanan Origin during the Cretaceous|journal=Molecular Biology and Evolution|volume=25|pages=2141–2156|doi= 10.1093/molbev/msn160|pmid=18653733|issue=10|pmc=2727385}}</ref><ref name=tokita>{{cite journal|doi=10.1111/j.1525-142X.2007.00199.x|last=Tokita |first=M |author2=Kiyoshi T |author3=Armstrong KN |year=2007|title=Evolution of craniofacial novelty in parrots through developmental modularity and heterochrony|journal=Evolution & Development|volume=9|issue=6|pages=590–601|url=http://www3.interscience.wiley.com/journal/118546207/abstract|archive-url=https://archive.today/20121005175548/http://www3.interscience.wiley.com/journal/118546207/abstract|url-status=dead|archive-date=5 October 2012|pmid=17976055|s2cid=46659963 }}</ref><ref name=deKloet>{{cite journal|last=de Kloet|first=RS|author2=de Kloet SR|year=2005|title=The evolution of the spindlin gene in birds: Sequence analysis of an intron of the spindlin W and Z gene reveals four major divisions of the Psittaciformes|journal=Molecular Phylogenetics and Evolution|volume=36|pages=706–721|doi=10.1016/j.ympev.2005.03.013|pmid=16099384|issue=3|bibcode=2005MolPE..36..706D }}</ref><ref name="Schweizer">{{cite journal|title=The evolutionary diversification of parrots supports a taxon pulse model with multiple trans-oceanic dispersal events and local radiations|journal=Molecular Phylogenetics and Evolution|year=2009|first=M. |last=Schweizer|pmid=19699808 |author2=Seehausen O |author3=Güntert M |author4=Hertwig ST|volume=54|doi= 10.1016/j.ympev.2009.08.021|issue=3|pages=984–94 |s2cid=1831016 }}</ref>

The origin of the budgerigar's name is unclear. First recorded in 1805, budgerigars are popular pets around the world due to their small size, low cost, and ability to mimic human speech. They are likely the third most popular pet in the world, after the domesticated [[dog]] and [[cat]].<ref name=":4">{{Cite encyclopedia|year=2003|title=Parrots, Lories, and Cockatoos|encyclopedia=The New Encyclopedia of Birds|publisher=Oxford University Press|url=https://www.oxfordreference.com/view/10.1093/acref/9780198525066.001.0001/acref-9780198525066-e-114?rskey=XgWhG8&result=112|access-date=10 September 2021|editor-last=Perrins|editor-first=Christopher|isbn=9780198525066|archive-date=9 September 2021|archive-url=https://web.archive.org/web/20210909230744/https://www.oxfordreference.com/view/10.1093/acref/9780198525066.001.0001/acref-9780198525066-e-114?rskey=XgWhG8&result=112|url-status=live}}</ref> Budgies are nomadic flock [[parakeet]]s that have been bred in captivity since the 19th century. In both captivity and the wild, budgerigars breed [[Opportunistic breeder|opportunistically]] and [[Breeding pair|in pairs]].

They are found wild throughout the drier parts of [[Australia]], where they have survived harsh inland conditions for over five million years. Their success can be attributed to a nomadic lifestyle and their ability to breed while on the move.<ref>{{cite web
  | title =Dr. Marshall's Philosophy on Breeding Exhibition Budgerigars
  | publisher =Bird Health
  | year =2004
  | url =http://www.birdhealth.com.au/bird/budgie/article.html
 |url-status=dead |archive-url=https://web.archive.org/web/20040811184656/http://www.birdhealth.com.au/bird/budgie/article.html
 |archive-date=11 August 2004 |access-date=4 November 2013}}</ref> 

== Etymology ==
Several possible origins for the name ''budgerigar'' have been proposed.
One origin could be that ''budgerigar'' may be a mispronunciation or alteration of the [[Gamilaraay language|Gamilaraay]] word ''gidjirrigaa'' ({{IPA-aus|ɡ̊iɟiriɡaː}})<ref>{{cite web |title=gidjirrigaa |website=Gamilaraay Dictionary |url=http://coombs.anu.edu.au/WWWVLPages/AborigPages/LANG/GAMDICT/GAM_G.HTM |url-status=dead |archive-url=https://web.archive.org/web/19970104042209/http://coombs.anu.edu.au/WWWVLPages/AborigPages/LANG/GAMDICT/GAM_G.HTM#G |archive-date=4 January 1997}}</ref><ref>{{cite encyclopedia |title=budgerigar |dictionary=Macquarie Dictionary |publisher=Macquarie Dictionary Publishers |url=https://www.macquariedictionary.com/features/word/search/?search_word_type=Dictionary&word=budgerigar |access-date=10 September 2021 }}{{Dead link|date=October 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> or ''gijirragaa'' from the Yuwaalaraay.<ref>{{cite encyclopedia |title=budgerigar |dictionary=Merriam-Webster.com |publisher=Merriam-Webster |url=https://www.merriam-webster.com/dictionary/budgerigar |access-date=10 September 2021|archive-date=9 September 2021 |archive-url=https://web.archive.org/web/20210909230744/https://www.merriam-webster.com/dictionary/budgerigar|url-status=live}}</ref>
Another possible origin is that ''budgerigar'' might be a modified form of ''budgery'' or ''boojery'' ([[Australian English]] slang for "good") and ''gar'' ("[[cockatoo]]").<ref>{{cite encyclopedia |title=budgerigar (''n''.) |dictionary=Online Etymology Dictionary |publisher=Douglas Harper |url=https://www.etymonline.com/word/budgerigar |url-status=live |access-date=10 September 2021 |archive-date=24 February 2017 |archive-url=https://web.archive.org/web/20170224132843/http://www.etymonline.com/index.php?term=budgerigar}}</ref>
While many references mention "good" as part of the meaning, and a few specify "good bird", it is quite possible that reports by those local to the region are more accurate in specifying the direct translation as "good food".<ref>{{cite web |editor=Hansen, Dave |title=History |publisher=Hamilton & District Budgerigar & Cage Bird Society |via=www3.sympatico.ca |url=http://www3.sympatico.ca/davehansen/hist.html |url-status=live |access-date=9 September 2021 |archive-date=27 August 2021 |archive-url=https://web.archive.org/web/20210827232919/http://www3.sympatico.ca/davehansen/hist.html}}</ref>

Alternative spellings include ''budgerygah'' and ''betcherrygah'',<ref name=Lendon73>{{cite book |last=Lendon |first=Alan H. |year=1973 |title=Australian Parrots in Field and Aviary |edition=2nd |publisher=Angus and Robertson |location=Sydney, NSW, AU |isbn=0-207-12424-8|pages=302–07}}</ref> the latter used by Indigenous people of the [[Liverpool Plains]] in [[New South Wales]].<ref>{{cite web |last=Gould |first=John |author-link=John Gould |year=2009 |title=Indigenous Bird Names of the Hunter Region of New South Wales |website=Australian Museum |location=Sydney, New South Wales |url=http://gould.australianmuseum.net.au/naturalist/indigenous2.htm |url-status=dead |archive-url=https://web.archive.org/web/20091017200317/http://gould.australianmuseum.net.au/naturalist/indigenous2.htm |archive-date=17 October 2009 |access-date=22 February 2010}}</ref>

Alternative names for the budgerigar include the ''shell parrot'' or ''shell parakeet'', the ''warbling grass parakeet'', the ''canary parrot'', the ''zebra parrot'', the ''flight bird'', and the ''scallop parrot''. Although more often used as a common name for small parrots in the genus ''[[Agapornis]]'', the name "lovebird" has been used for budgerigars, because of their habit of close perching, mutual preening, and their long term pair-bonds.<ref name=Lendon73/>

== Taxonomy ==
{{cladogram
 |title=Evolutionary history
 |align=left
 |caption=Phylogenetic chart<ref name=wright /><ref name=tokita/><ref name=deKloet/><ref name="Schweizer" />
|{{clade
  |label1=&nbsp; [[parrots]] &nbsp;
  |1=
   {{clade
    |{{clade
      |label1=&nbsp;
      |1={{clade
        |label1=&nbsp;
        |1={{nobr|&nbsp; [[Lories and lorikeets]] &nbsp;}}
        |label2= &nbsp;
        |2=&nbsp; Budgerigar
        }}
      |label2=&nbsp; [[Fig parrot]]s &nbsp;
      |2={{center|&nbsp; genera ''[[Cyclopsitta]]'' & ''[[Psittaculirostris]]'' &nbsp;}}
      }}
    |label2=&nbsp;
    |2=&nbsp;... other parrots
    }}
  }}
}}

The budgerigar was first described by [[George Shaw (biologist)|George Shaw]] in 1805, and given its current binomial name by [[John Gould]] in 1840. The genus name ''Melopsittacus'', from [[Ancient Greek language|Ancient Greek]], means "melodious parrot".<ref name=Liddell1980>{{cite book | author = Liddell, H.G. | author-link = Henry George Liddell | author2 = Robert Scott | author2-link = Robert Scott (philologist) | name-list-style=amp| year = 1980 | title = A Greek-English Lexicon | publisher = [[Oxford University Press]] | location = United Kingdom | isbn = 0-19-910207-4 | url-access = registration | url = https://archive.org/details/lexicon00lidd | edition = Abridged }}</ref> The species name ''undulatus'' is [[Latin language|Latin]] for "undulated" or "wave-patterned".<ref>{{cite book | last = Simpson | first = D.P. | title = Cassell's Latin Dictionary | publisher = Cassell Ltd. | year = 1979 | edition = 5th | location = London | isbn = 0-304-52257-0}}</ref>

The budgerigar was once proposed to be a link between the genera ''[[Neophema]]'' and ''[[Pezoporus]]'', based on the barred plumage.<ref name="forshaw" /> However, recent [[phylogenetic]] studies using DNA sequences place the budgerigar very close to the [[lories and lorikeets|lories]] ([[tribe (biology)|tribe]] [[Loriini]]) and the [[fig parrot]]s (tribe [[Cyclopsittini]]).<ref name=wright /><ref name=tokita /><ref name=deKloet /><ref name="Schweizer" />

== Description ==
[[File:Budgerigar diagram-labeled.svg|thumb|Anatomy of a male budgerigar]]

Wild budgerigars average {{convert|18|cm|in|0|abbr=on}} long,<ref name=":3" /> weigh {{convert|30|-|40|g|oz}}, {{convert|30|cm|in|0|abbr=on}} in wingspan, and display a light green body colour (abdomen and rumps), while their mantles (back and wing coverts) display pitch-black mantle markings (blackish in fledglings and immatures) edged in clear yellow undulations. The forehead and face is yellow in adults. 

Prior to their adult [[plumage]], young individuals have blackish stripes down to the cere (nose) in young individuals until around 3–4 months of age. They display small, iridescent blue-violet cheek patches and a series of three black spots across each side of their throats (called throat patches). The two outermost throat spots are situated at the base of each cheek patch. The tail is cobalt (dark-blue); and outside tail [[feathers]] display central yellow flashes. Their wings have greenish-black flight feathers and black coverts with yellow fringes along with central yellow flashes, which only become visible in flight or when the wings are outstretched. Bills are olive grey and legs blueish-grey, with [[Dactyly#Zygodactyly|zygodactyl]] toes.<ref name="forshaw">{{cite book|last1=Forshaw|first1=Joseph Michael|title=Parrots of the World|last2=Cooper|first2=William T.|publisher=Princeton University Press|others=Illustrated by Frank Knight|year=1981|isbn=0-87666-959-3|edition=2nd|pages=175–176|orig-year=and 1st edition in 1973}}</ref>

In their natural [[Australia]]n habitat, budgerigars are noticeably smaller than those in [[captivity (animal)|captivity]].<ref name="budgerigar.com">{{Cite web|url=http://www.budgerigar.com|url-status=dead|archive-url=https://web.archive.org/web/20180920111939/http://budgerigar.com/|title=Budgerigar.com|archive-date=20 September 2018}}</ref> This particular parrot species has been bred in many other colours and shades in captivity (e.g. blue, grey, grey-green, pieds, violet, white, yellow-blue). Pet store individuals will commonly be blue, green, or yellow. Like most parrot species, budgerigar plumage fluoresces under ultraviolet light – a phenomenon possibly related to [[courtship display|courtship]] and mate selection.<ref name=":1" /><ref name=UV>{{cite journal |author1=S M Pearn |author2=A T Bennett |author3=I C Cuthill  |name-list-style=amp| year=2001 | pmc=1088876 | title=Ultraviolet vision, fluorescence and mate choice in a parrot, the budgerigar Melopsittacus undulatus | volume=268 | issue=1482 | pmid=11674876 | pages=2273–9 | doi=10.1098/rspb.2001.1813 | journal=Proceedings: Biological Sciences }}</ref>

The colour of the [[cere]] (the area containing the nostrils) differs between the [[sex]]es, being a lavender/baby blue in males, pale brownish/white (non breeding) to brown ([[Reproduction|breeding]]) in females, and pink in immature birds of both sexes (usually of a more even purplish-pink colour in young males).<ref name=":2" /> Some female budgerigars develop brown cere only during breeding time, which later returns to the normal colour.<ref name=":2" /> Young females can often be identified by a subtle, chalky whiteness that starts around the nostrils. Males that are either [[Ino budgerigar mutation|albino, lutino]], [[Clearflight Pied budgerigar mutation|dark-eyed clear]] or [[Recessive Pied budgerigar mutation|recessive pied]] (Danish pied or harlequin) retain the immature purplish-pink cere colour for their entire lives.<ref name=forshaw /><ref name=sex>{{cite web | url=http://www.birds-online.de/allgemein/geschlecht_en.htm | title=Birds Online&nbsp;— How to tell the sex of a budgie | access-date=25 April 2006 | archive-date=4 February 2019 | archive-url=https://web.archive.org/web/20190204120418/http://www.birds-online.de/allgemein/geschlecht_en.htm | url-status=live }}</ref>
[[File:Budgerigar- Mount Hope.jpg|thumb|Wild budgerigars in flight at Mount Hope, New South Wales, Australia]]

Mature males usually have a cere of light to dark blue, but in some particular colour mutations it can be periwinkle, lavender, purplish or pink – including dark-eyed clears, Danish pieds (recessive pieds) and inos, which usually display much rounder heads. Female budgerigars display more [[Dominance hierarchy|dominant behaviour]] compared to males of the species and may act aggressively towards them.<ref>{{cite journal |last1=Hile |first1=Arla |last2=Burley |first2=Nancy |last3=Coopersmith |first3=Carol |last4=Foster |first4=Valerie |title=Effects of Male Vocal Learning on Female Behavior in the Budgerigar, Melopsittacus undulatus |journal=Ethology |date=2005 |volume=111 |issue=10 |pages=901–923 |doi=10.1111/j.1439-0310.2005.01105.x |bibcode=2005Ethol.111..901H |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1439-0310.2005.01105.x |access-date=2 June 2024}}</ref>

Budgerigars have [[tetrachromatic]] [[colour vision]], although all four classes of [[cone cell]]s will not operate simultaneously unless under [[sunlight]] or a [[UV lamp]].<ref>Color Vision of the Budgerigar (Melopsittacus undulatus): Hue Matches, Tetrachromacy, and Intensity Discrimination. <br />Timothy H. Goldsmith and Byron K. Butler in Journal of Comparative Physiology A, Vol. 191, No. 10, pages 933–951; October 2005.</ref> The [[ultraviolet]] spectrum brightens their feathers to attract mates. The throat spots in budgerigars reflect UV and can be used to distinguish individual birds.<ref name=UV /> While ultraviolet light is essential to the good health of caged and pet birds, inadequate darkness or rest results in overstimulation.<ref>{{cite book|title=Budgerigars: Everything about Purchase, Care, Nutrition, Behavior, and Training|url=https://archive.org/details/budgerigarsevery00niem|url-access=registration|author=Hildegard Niemann|publisher=Barron's Educational Series, 2008|isbn=9780764138973|page=[https://archive.org/details/budgerigarsevery00niem/page/59 59]|year=2007}}</ref>

=== Colour mutations ===
{{Main|Budgerigar colour genetics}}
All captive budgerigars are divided into two basic series of colours; namely, white-based (blue, grey and white) and yellow-based (green, grey-green and yellow).<ref name=":2" /> Presently, at least 32 primary [[mutation]]s (including violet) occur, enabling hundreds of possible secondary mutations (stable combined primary mutations) and colour varieties (unstable combined mutations).<ref name=":2" />

== Ecology ==
[[File:Verbreitungsgebiet Wellensittiche.svg|200px|thumb|right|Distribution map of budgerigar in Australia<br/>
'''Distribution area'''
{{Legend|white|Frequent occurrence|text=[[File:Black legend stripes.svg|32px|link=]]|outline=black;width:32px!important;height:21px!important}}
{{Legend|white|Occasional occurrence|text=[[File:Black legend stripes-dashed.svg|link=]]|outline=black;width:32px!important;height:21px!important}}
----
{| class="collapsible collapsed"
!Climate region key
|-
|{{Legend|#7c913a|[[Equatorial climate|Equatorial]]}}
{{Legend|#63ac45|[[Tropical climate|Tropical]]}}
{{Legend|#95c93d|[[Subtropical climate|Subtropical]]}}
{{Legend|#d2da95|[[Grassland climate|Grassland]]}}
{{Legend|#d2ba61|[[Desert climate|Desert]]}}
{{Legend|#1e4288|[[Temperate climate|Temperate]]}}
|}]]
Budgerigars are nomadic and [[Herd|flocks]] move on from sites as environmental conditions change.<ref name=":4" /><ref name="Pranty 2001">Pranty 2001</ref><ref name=":3" /> Budgerigars are found in open habitats, primarily in [[scrubland]]s, open [[woodland]]s, and [[grassland]]s of Australia.<ref name=":4" /> The birds are normally found in small flocks, but can form very large flocks under favourable conditions.<ref name=":4" /> The nomadic movement of the flocks is tied to the availability of [[food]] and [[water]].<ref name=forshaw /> Budgerigars have two distinct flight speeds which they are capable of switching between depending on the circumstance.<ref>Ingo Schiffner and Mandyam Srinivasan (2016) Budgerigar flight in a varying environment: flight at distinct speeds?, https://doi.org/10.1098/rsbl.2016.0221 {{Webarchive|url=https://web.archive.org/web/20220425223423/https://royalsocietypublishing.org/doi/10.1098/rsbl.2016.0221 |date=25 April 2022 }}</ref> Budgerigars sometimes [[Swarm behaviour|swarm]] together in groups containing thousands of individuals.<ref>{{cite news |last1=Haskin |first1=Emma |title=Budgies swarm in outback Australia as wildlife photographer stands ready to capture images |url=https://www.abc.net.au/news/2017-10-10/budgies-swarm-in-central-australia-stunning-display/9035030 |website=ABC News |date=10 October 2017 |access-date=2 June 2024}}</ref>

[[Drought]] can drive flocks into more wooded habitat or coastal areas. They feed on the [[seeds]] of [[Triodia (plant genus)|spinifex]] and [[grass]], and sometimes ripening [[wheat]].<ref name=forshaw /><ref name="wild budgie">{{cite web | url=http://freespace.virgin.net/cobber.budgies/wildphoto.html | title=The Wild Budgerigar | format=article | access-date=25 April 2006 | archive-url=https://web.archive.org/web/20090306224245/http://freespace.virgin.net/cobber.budgies/wildphoto.html | archive-date=6 March 2009 | url-status=dead }}</ref><ref name=":2" /><ref name=":3" /> Budgerigars feed primarily on grass seeds.<ref name="Pranty 2001"/><ref name=":2" /> The species also opportunistically depredates growing cereal crops and lawn grass seeds.<ref>Stevenson & Anderson 1994</ref> Due to the low water content of the seeds they rely on the availability of freshwater.<ref name=":2" />

Outside of Australia, the only long-term establishment of naturalised [[feral]] budgerigars is a large population near [[St. Petersburg, Florida|St. Petersburg]], [[Florida]].<ref name="forshaw" /> Increased competition for nesting sites from [[European starling]]s and [[house sparrow]]s is thought to be a primary cause of the Florida population declining from the 1980s.<ref name="Pranty 2001"/> The more consistent, year-round conditions in Florida significantly reduced their nomadic behaviour.<ref>Shapiro 1979<!--in Pranty '01--></ref> The species has been introduced to various locations in Puerto Rico and the United States.<ref name=IUCN/>

== Behaviour ==
=== Breeding ===
Breeding in the wild generally takes place between June and September in northern Australia and between August and January in the south, although budgerigars are [[opportunistic breeders]] and respond to rains when grass seeds become most abundant.<ref name=":3" /><ref name=":2" /><ref name=forshaw />  Budgerigars are monogamous and breed in large colonies throughout their range.<ref>{{Cite web |last=Sims |first=Kelly |title=''Melopsittacus undulatus'' (budgerigar) |url=https://animaldiversity.org/accounts/Melopsittacus_undulatus/ |access-date=2023-10-27 |website=Animal Diversity Web |language=en}}</ref> They show signs of affection to their flockmates by preening or feeding one another. Budgerigars feed one another by eating the seeds themselves, and then regurgitating it into their flockmate's mouth. Populations in some areas have increased as a result of increased water availability at [[farm]]s. [[Bird nest|Nests]] are made in holes in trees, fence posts or logs lying on the ground; the four to six [[bird egg|eggs]] are incubated for 18–21 days, with the young [[fledge|fledging]] about 30 days after hatching.<ref name=forshaw /><ref name="wild budgie" /><ref name=":3" /><ref name=":4" /> In the wild, virtually all parrot species require a hollow tree or a hollow log as a nest site.<ref name=":2" /> Budgerigars will typically breed in [[captivity (animal)|captivity]] when provided with a [[nest box]].<ref>{{cite journal |last1=Brockway |first1=Barbara |title=Hormonal and Experiential Factors Influencing the Nestbox Oriented Behaviour of Budgerigars (''Melopsittacus undulatus'') |journal=Behaviour |date=1964 |volume=35 |issue=1 |page=2}}</ref>

The eggs are typically one to two centimetres long and are pearl white without any colouration if fertile. Female budgerigars can lay eggs without a male partner, but these unfertilised eggs will not hatch. Females normally have a whitish tan cere; however, when the female is laying eggs, her cere turns a crusty brown colour. Certain female budgies may always keep a whitish tan cere or always keep a crusty brown cere regardless of breeding condition. A female budgerigar will lay her eggs on alternating days.<ref name="Talk Budgies&nbsp;— Breeding">{{cite web |url=http://talkbudgies.com/showthread.php?t=14758 |title=Talk Budgies&nbsp;— Breeding |access-date=4 November 2013 |archive-date=23 September 2018 |archive-url=https://web.archive.org/web/20180923235317/https://www.talkbudgies.com/showthread.php?t=14758 |url-status=live }}</ref> After the first one, there is usually a two-day gap until the next. She will usually lay between four and eight eggs, which she will incubate (usually starting after laying her second or third) for about 21 days each.<ref name="Talk Budgies&nbsp;— Breeding" /> Females only leave their nests for very quick defecations, stretches and quick meals once they have begun incubating and are by then almost exclusively fed by their mate (usually at the nest's entrance). Females will not allow a male to enter the nest, unless he forces his way inside.<ref name="Talk Budgies&nbsp;— Breeding" /> Clutch size ranges from 6 to 8 chicks.<ref name=":3" />

There is evidence of same-sex sexual behaviour amongst male budgerigars.<ref name=":1">{{Cite journal|last1=Abbassi|first1=Puya|last2=Burley|first2=Nancy Tyler|date=1 July 2012|title=Nice guys finish last: same-sex sexual behavior and pairing success in male budgerigars|journal=Behavioral Ecology|volume=23|issue=4|pages=775–782|doi=10.1093/beheco/ars030|issn=1045-2249|doi-access=free|hdl=10.1093/beheco/ars030|hdl-access=free}}</ref> It was originally hypothesised that they did this as a form of "courtship practice" so they were better breeding partners for females; however, an inverse relationship exists between participation in same-sex behaviour and pairing success.<ref name=":1" />

=== Chick health ===
[[File:Melopsittacus undulatus -chicks and eggs in a nest box-8a.jpg|thumb|The chicks and eggs of budgerigar in nest box]]
Breeding difficulties arise for various reasons. Some chicks may die from diseases and attacks from adults. Other budgerigars (virtually always females) may fight over the nest box, attacking each other or a brood. Another problem may be the birds' [[Crossed beak|beaks being under-lapped]], where the lower mandible is above the upper mandible.<ref>{{Cite web |last=Helton |first=Lindsay |date=2021-10-25 |title=Cross Beak |url=https://amerpoultryassn.com/2021/10/cross-beak/ |access-date=2024-04-26 |website=American Poultry Association |language=en-US}}</ref> 

Most health issues and physical abnormalities in budgerigars are genetic. Care should be taken that birds used for breeding are active, healthy and unrelated. Budgerigars that are related or have fatty tumours or other potential genetic health problems should not be allowed to breed. Parasites (lice, mites, worms) and pathogens (bacteria, fungi and viruses), are contagious and thus transmitted between individuals through either direct or indirect contact.{{Citation needed|date=September 2021}}

In some cases, chicks will experience [[Spraddle leg|splay leg]]. This medical condition may be [[congenital]] or acquired through malnutrition. Chicks can be treated with [[Splint (medicine)|splints]] although this method is not always successful in curing the affected bird. Preventative measures include using proper nesting box materials such as pine shavings<ref>{{cite web |title=Splayed Legs in Budgerigars |url=https://bcsa.com.au/breeding/splayed-legs/ |website=Budgerigar Council of Australia |access-date=2 June 2024}}</ref> and cleaning the nest box between uses.<ref>{{cite web |last1=Baron |first1=Hamish |title=Splayed Legs |url=http://www.world-budgerigar.org/Splayed%20Legs%20by%20Dr.%20Hamish%20Baron.pdf |website=World Budgerigar Organisation |access-date=2 June 2024}}</ref>

=== Development ===
[[File:Female budgerigar and her chick .jpg|thumb|right|A three-week-old chick beginning to develop feathers and adult coloration.]]
Eggs take about 18–20 days before they start hatching.{{Citation needed|date=September 2021}} The hatchlings are [[altricial]]&nbsp;– blind, naked, unable to lift their head and totally helpless,<ref name=":2" /><ref name=":3" /> and their mother feeds them and keeps them warm constantly. Around 10 days of age, the chicks' eyes will open, and they will start to develop [[down (feather)|feather down]]. The appearance of down occurs at the age for closed banding of the chicks.

They develop [[feather]]s around three weeks of age. (One can often easily note the colour mutation of the individual birds at this point.) At this stage of the chicks' development, the male usually has begun to enter the nest to help his female in caring and feeding the chicks. Some budgerigar females, however, totally forbid the male from entering the nest and thus take the full responsibility of rearing the chicks until they fledge.{{Citation needed|date=September 2021}}

Depending on the size of the clutch and most particularly in the case of single mothers, it may then be wise to transfer a portion of the hatchlings (or best of the fertile eggs) to another pair. The foster pair must already be in breeding mode and thus either at the laying or incubating stages, or already rearing hatchlings.{{Citation needed|date=September 2021}}

As the chicks develop and grow feathers, they are able to be left on their own for longer periods of time. By the fifth week, the chicks are strong enough that both parents will be comfortable in staying out of the nest more. The youngsters will stretch their wings to gain strength before they attempt to [[flight|fly]]. They will also help defend the box from enemies, mostly with their loud screeching. Young budgerigars typically fledge (leave the nest) around their fifth week of age and are usually completely weaned between six and eight weeks old. However, the age for fledging, as well as weaning, can vary slightly depending on the age and the number of surviving chicks. Generally speaking, the oldest chick is the first to be weaned. Although it is logically the last one to be weaned, the youngest chick is often weaned at a younger age than its older sibling(s). This can be a result of mimicking the actions of older siblings. Lone surviving chicks are often weaned at the youngest possible age as a result of having their parents' full attention and care.{{Citation needed|date=September 2021}}

Hand-reared budgies may take slightly longer to wean than parent-raised chicks. Hand feeding is not routinely done with budgerigars, due to their small size and because young parent raised birds can be readily tamed.{{Citation needed|date=September 2021}}

== Relationship with humans ==
=== Aviculture ===
[[File:Melopsittacus undulatus - English Budgie and American Parakeets.jpg|thumb|right|Exhibition style "budgie" (left), as compared to pet-type budgerigars]]
The budgerigar has been bred in captivity since the 1850s. Breeders have worked to produce a variety of colour, pattern and feather mutations, including [[albino]], [[Blue budgerigar mutation|blue]], cinnamon-ino (lacewing), clearwing, crested, [[dark budgerigar mutation|dark]], greywing, opaline, pieds, spangled, [[dilute budgerigar mutation|dilute (suffused)]] and [[violet budgerigar mutation|violet]].<ref name=":2" />

"English budgerigars", more correctly called "show" or "exhibition budgerigars", are about twice as large as their wild counterparts and have puffier head feathers, giving them a boldly exaggerated look. The eyes and beak can be almost totally obscured by these fluffy head feathers. English budgerigars are typically more expensive than wild-type birds, and have a shorter life span of about seven to nine years. Breeders of English budgerigars show their birds at [[show (animal)|animal shows]]. Most captive budgerigars in the pet trade are more similar in size and body conformation to wild budgerigars.<ref>{{Cite web |last=birdy |date=2022-06-02 |title=English budgie vs American budgie {{!}} Which one is Better? |url=https://birdsology.com/english-budgie-vs-american-budgie/ |access-date=2023-04-29 |website=birdsology |language=en-US}}</ref>

Budgerigars are social animals and require stimulation in the shape of toys and interaction with humans or with other budgerigars. Budgerigars, and especially females, will chew material such as [[wood]]. When a budgerigar feels threatened, it will try to perch as high as possible and to bring its feathers close against its body in order to appear thinner.{{Citation needed|date=September 2021}}

Tame budgerigars can be taught to [[talking bird|speak]], [[whistling|whistle]] and play with humans. Both males and females sing and can learn to mimic sounds and words and do simple tricks, but singing and mimicry are more pronounced and better perfected in males. Females rarely learn to mimic more than a dozen words. Males can easily acquire vocabularies ranging from a few dozen to a hundred words. Pet males, especially those kept alone, are generally the best speakers.<ref>{{Cite book|last=Moustaki|first=Nikki|title=Parakeets for dummies|date=2007|publisher=Wiley|isbn=9781118068281|location=Hoboken, N.J.|oclc=785572631}}</ref>

Budgerigars will chew on anything they can find to keep their beaks trimmed. Mineral blocks (ideally enriched with iodine), [[cuttlebone]] and soft wooden pieces are suitable for this activity. Cuttlebones also supply calcium, essential for the proper forming of eggs and bone solidity. In captivity, budgerigars live an average of five to eight years, but life spans of 15–20 years have been reported.<ref>{{cite web | url=http://www.birds-online.de/allgemein/alter_en.htm | title=Birds Online&nbsp;— Life span of a budgie | access-date=26 December 2005 | archive-date=4 February 2019 | archive-url=https://web.archive.org/web/20190204120421/http://www.birds-online.de/allgemein/alter_en.htm | url-status=live }}</ref> The life span depends on breed, lineage, and health, being highly influenced by [[exercise]] and [[diet (nutrition)|diet]]. Budgerigars have been known to cause "[[bird fancier's lung]]" in sensitive people, a type of [[hypersensitivity pneumonitis]].<ref>{{cite journal | pmid = 566603 | volume=2 | issue=6130 | title=Budgerigar-fancier's lung: the commonest variety of allergic alveolitis in Britain | pmc=1605890 |date=July 1978 | journal=Br Med J | pages=81–4 | doi=10.1136/bmj.2.6130.81| last1=Hendrick | first1=D. J. | last2=Faux | first2=J. A. | last3=Marshall | first3=R }}</ref> Apart from a handful of illnesses, diseases of the species are not transmittable to humans.<ref>{{cite book|title=Budgerigars: Everything about Purchase, Care, Nutrition, Behavior, and Training|url=https://archive.org/details/budgerigarsevery00niem|url-access=registration|author=Hildegard Niemann|publisher=Barron's Educational Series, 2008|isbn=9780764138973|page=[https://archive.org/details/budgerigarsevery00niem/page/62 62]|year=2007}}</ref>

=== Mimicry ===
{{Main|Talking bird}}
Budgerigars, like many other species of parrot, are able to mimic human speech.<ref>{{cite journal |last1=Bradbury |first1=Jack |last2=Balsby |first2=Thorston |title=The functions of vocal learning in parrots |journal=Behavioral Ecology and Sociobiology |date=2016 |volume=70 |issue=3 |page=294|doi=10.1007/s00265-016-2068-4 |bibcode=2016BEcoS..70..293B }}</ref> Puck, a male budgerigar owned by American Camille Jordan, holds the world record for the largest vocabulary of any bird, at 1,728 words. Puck died in 1994, with the record first appearing in the 1995 edition of [[Guinness World Records]].<ref>{{cite book |editor= Claire Folkard |title=Guinness World Records 2004 |publisher=Guinness World Records Limited |isbn=0-85112-180-2 |page= 54|year=2003 }}</ref><ref>{{cite web |url=http://birdwithmostwords.com/ |title=The Bird with the Largest Vocabulary in the World |url-status=dead |archive-url=https://web.archive.org/web/20070928044747/http://birdwithmostwords.com/ |archive-date=28 September 2007 |access-date=4 November 2013}}</ref> The budgerigar "Disco" became Internet famous in 2013.<ref>{{cite web |url=https://www.npr.org/blogs/thetwo-way/2013/07/23/204898898/watch-disco-the-parakeet-takes-on-monty-python |title=WATCH: Disco, The Parakeet, Takes On 'Monty Python' |website=[[NPR]] |date=23 July 2013 |access-date=4 November 2013 |archive-date=22 October 2013 |archive-url=https://web.archive.org/web/20131022034339/http://www.npr.org/blogs/thetwo-way/2013/07/23/204898898/watch-disco-the-parakeet-takes-on-monty-python |url-status=live |last1=Peralta |first1=Eyder }}</ref> Some of Disco's most repeated phrases included, "[[I am not a crook]]" and "Nobody puts baby bird in a corner!".<ref>{{cite web|url=http://now.msn.com/disco-the-parakeet-banters-beatboxes-and-blows-minds |title=Disco the parakeet will blow your mind with his vintage banter |url-status=dead |access-date=4 November 2013 |archive-url=https://web.archive.org/web/20131022020159/http://now.msn.com/disco-the-parakeet-banters-beatboxes-and-blows-minds |archive-date=22 October 2013 }}</ref>

== In popular culture ==
[[Swim briefs|Small bathing suits]] for men, commonly referred to as togs or "Speedos", are informally called "budgie smugglers" in Australia. The phrase is humorously based on the appearance of the tight-fitting cloth around the male's genitals looking like a small budgie. The phrase was added to the Oxford English Dictionary in 2016.<ref>{{Cite news|url=http://www.abc.net.au/news/2016-07-08/budgie-smugglers-officially-added-to-oxford-english-dictionary/7580368|title='Budgie smugglers' officially added to Oxford English Dictionary|date=8 July 2016|work=ABC News|language=en-AU|access-date=6 April 2018|archive-date=11 April 2018|archive-url=https://web.archive.org/web/20180411084030/http://www.abc.net.au/news/2016-07-08/budgie-smugglers-officially-added-to-oxford-english-dictionary/7580368|url-status=live}}</ref>

==Gallery==

<gallery>
File:Açık mavi muhabbet kuşu.jpg|Pet budgerigar with a light blue colour
Muhabbet kuşu açık mavi.jpg|Patagonian budgerigar
Melopsittacus undulatus (24082227505).jpg|Budgerigars perched in a tree
Melopsittacus undulatus flock 4.jpg|Budgerigar flock up-close
Melopsittacus undulatus flock 3.jpg|Large flock of budgerigars
Budgerigar Flock Melopsittacus undulatus near Tibooburra NSW.jpg|Budgerigars in flocks in their natural habitat
Melopsittacus undulatus -Cologne Zoo -pair-8a.jpg|A budgerigar family
Budgerigar (Karayil).jpg|A white budgerigar
Budgerigar - kanagawa - 2023 3 12.webm|Budgerigars interacting in captivity in [[Japan]]
Handaufzucht Wellensittich Melopsittacus undulatus.jpg|A budgerigar chick being hand-reared after the death of the female
</gallery>

== See also ==

* [[Budgerigar colour genetics]]
* [[Sparkie Williams|Sparkie (budgerigar)]]
* [[Talking bird]]
* [[Whipper (budgerigar)]]

== References ==
{{Reflist}}

== Bibliography ==
* Pranty, B. 2001. The Budgerigar in Florida: Rise and fall of an exotic psittacid. North American Birds 55: 389–397.
* Forshaw, Joseph M. & Cooper, William T. (1978): ''Parrots of the World'' (2nd ed). Landsdowne Editions, Melbourne Australia {{ISBN|0-7018-0690-7}}
* Collar, N. J. (1997). Budgerigar (''Melopsittacus undulatus''). Pg. 384 in: del Hoyo, J., Elliott, A. & Sargatal, J. eds. (1997).<br /> ''Handbook of the Birds of the World.'' Vol. 4. Sandgrouse to Cuckoos. Lynx Edicions, Barcelona. {{ISBN|84-87334-22-9}}

== Further reading ==
{{Commons category}}
{{Wikispecies|Melopsittacus undulatus}}
* {{Wiktionary-inline|budgerigar}}
* [http://www.parrots.org/index.php/encyclopedia/profile/budgerigar/ World Parrot Trust] Parrot Encyclopedia&nbsp;— Species Profiles
* [https://archive.today/20121216083747/http://www.holisticbirds.com/pages/budgie0601.htm A True Ambassador: the Budgerigar] Referenced article on budgerigars
* [https://web.archive.org/web/20190715051041/http://pre.ensembl.org/Melopsittacus_undulatus/Info/Index Budgerigar genome] in [[Ensembl]]
* {{UCSC genomes|melUnd1}}

{{Budgerigar mutations}}
{{Psittacopasseres|Ps.|state=collapsed}}
{{Taxonbar|from=Q121221}}
{{Authority control}}

[[Category:Platycercini]]
[[Category:Endemic birds of Australia]]
[[Category:Talking birds]]
[[Category:Feral parrots]]
[[Category:Birds described in 1805]]
[[Category:Articles containing video clips]]
[[Category:Extant Pliocene first appearances]]
[[Category:Taxa named by George Shaw]]