What can 'nest', 'barb', 'spear', 'leaf', 'hair' and 'shoulder' have to do with one another? They all appear to be linked through 'manga / munga'.
The basic idea appears to be 'strand', 'thread'.
NEST
A nest is composed of many strands:
"munga" manga = "a nest" nest: [4] Grey 1840 [:120:45] [NYUNGAR]
"Mân-ga" manGa = "Bird, (nest of)" nest: Symmons, Charles [:7:55] [NYUNGAR]
BARB
Grey, below, links 'barb' and 'hair'. A barb is a single point, and a hair a single strand.
"mun-gar" munGa = "barb, a; hair" barb: [4] Grey 1840 [:210:11] [NYUNGAR]
"Man-gar" manGa = "Barb of a spear ..." barb: Moore 1842 [:68:21] [NYUNGAR]
SPEAR
Whether Hassell below was correct or not in stating 'munga' meant a type of 'spear' is not known. The reference could have been to 'barb', a feature of the spear concerned:
"mungar" munga = "hunting spears" spear: [11] Hassell AA 1894 [?] [:293:36] [NYUNGAR]
"mungay" manga = "fishing spears" spear: [11] Hassell AA 1894 [?] [::] [NYUNGAR]
Salvado defines 'reed spear': 'gidyi' is a common word for 'spear'; and 'reed' is yet another 'strand'.
"mangarghichi" manga gidyi = "spear, reed" barb spear: [8] Salvado 1851 [:388:45] [NYUNGAR]
LEAF
Symmons in describing fig leaves uses 'leaf' ('manga") with a plural marker: '-ra':
"Mân-ga-ra" manGara = "Hottentot fig (leaves of)" leaf: Symmons, Charles [:7:29] [NYUNGAR]
HAIR
The following examples indicate that 'manga' also stood for hair. 'gada' means 'head:
"munga" munga = "hair" hair: [23] Buller-Murphy [:279:43] [Dordenup [Wardandi]]
"mungar" munga = "hair of the head" hair: [10 (n)] Curr [:280:23] [Kaniyang]
"karta munga" gada manga = "hair (on head)" hair: [23] Buller-Murphy [:280:5] [Dordenup [Wardandi]]
"katta mangara" gada mangara = "hair of the head" hair: [6] Brady 1845 [:280:11] [NYUNGAR]
SHOULDER
This last example would suggest that the wordlist compilers might have erred. 'Hair' might have reached the 'shoulder', giving rise to misunderstanding. But who is to say now whether they were right or wrong?
"monga" manga = "shoulder" shoulder: [3] Lyon 1833 [:375:28] [NYUNGAR]
"mongo" manga = "shoulder" shoulder: [8 (E)] Salvado [:375:29] [Balardung]