Editing Java sparrow (section)

==Description==
The Java sparrow is about {{convert|15|to|17|cm|in|abbr=on}} in length from the beak to its tip of tail feathers.  Although only about the size of a [[house sparrow]], it may be the largest species in the estrildid family. The mean body mass is {{convert|24.5|g|oz|abbr=on}}, making it slightly heavier than its nearest known rival, the [[black-bellied seedeater]].<ref>{{cite book |title=CRC Handbook of Avian Body Masses |edition=2nd |editor-first=John B. Jr. |editor-last=Dunning |publisher=CRC Press |year=2008 |isbn=978-1-4200-6444-5}}</ref> The adult is unmistakable, with its grey upperparts and breast, pink belly, white-cheeked black head, red eye-ring, pink feet and thick red [[beak|bill]].

Both sexes are similar. Immature birds have brown upperparts and pale brown underparts, and a plain head. Very young birds have a black beak with a pink base.

The call is a ''chip'', and the song is a rapid series of call notes ''chipchipchipchipchipchip''.

Java sparrows produce distinct trill-calls in different behavioral contexts, according to a study by Furutani et al. (2018). These trill-calls, though acoustically similar, vary based on their repetition rate, which changes depending on the situation. In aggressive interactions, the sparrows emit faster trill-calls with higher sound pressure levels and entropy. In contrast, during affiliative behaviors, the trill-calls are slower and softer. This variation in trill-calls plays a crucial role in the birds' social communication, helping them convey different intentions based on the context.<ref>{{Cite journal |last1=Furutani |first1=A. |last2=Mori |first2=C. |last3=Okanoya |first3=K. |title=Trill-calls in Java sparrows: Repetition rate determines the category of acoustically similar calls in different behavioral contexts |journal=Behavioural Processes |date=December 2018 |volume=157 |pages=68–72 |doi=10.1016/j.beproc.2018.08.010 |pmid=30157464 |eissn=1872-8308 }}</ref>