v1.0
Published 01/10/24
gawlin ‘a type of bird’ is found in Martin’s Description of the Western Islands of Scotland (1703, 71–72), but the form gowlin occurs twice in his list of contents. SND˄ suggests that gawlin is probably from an unrecorded Scottish Gaelic form of ON gagl nt. ‘small goose’, f. ‘greylag’ (NO), comparing the Nynorsk reflex gaul (Torp 1992, s.v. gagl), but ON gagl might be expected to yield SG *[ˈɡ̊ɑːɫ̪] or [ˈɡ̊əːɫ̪], with compensatory lengthening of the vowel after loss of the original Old Norse fricative [ɣ], cf. ON *hugl ‘hill’ > SG tùl, ON Magnús m. pers. name > SG Mànas, and ON Rǫgnvald acc. m. pers. name > SG Raghnall [əː] (Cox 2022, 203). Henderson (1910, 129) suggests gowlin may be for gulönd (cf. Cleasby 1874: Ice. gul-önd ‘a kind of duck’), 
McDonald (2009, 359–60) considers the loan uncertain, later (2015, 124) unlikely.
i.e. ON *gul-ǫnd lit. ‘yellow-duck’, which may apply to the goosander, Mergus merganser, which has a cream breast. However, ON *gul-ǫnd would be expected to yield SG *gulann *[ˈɡ̊uɫ̪əᵰ̪] or similar. At any rate, Martin describes the bird in question as ‘a fowl less than a duck’.
Martin’s gowlin may imply Scots /ʌu/ or perhaps /uː/ for SG /ɔu/ or /oː/ in SG gobhlan m. [ˈɡ̊ɔuɫ̪an], [ˈɡ̊oːɫ̪an], 
Cf. SG gobhlan-gaoithe ‘swallow’ [koulɑn-ˈköːɣ] (Holmer 1938, 176: Islay), [koːlan-ˈkuiə] (ibid.: Skye), [goːɫan gɛːç] (Holmer 1962, 46: Kintyre), and, with shortening in weakly stressed position, [ɡ̊oʟɑn ˈɡ̊ɯːhi] (Wentworth 2003: Gairloch), [ɡuɫɑṉ]-gaoith (Faclan bhon t-Sluagh˄: ‘wagtail’, Glenlyon), gobhlachan-gaoithe /ɡɔl(ə)xɑn ɡɤiː/ (Watson 2022, 216: Easter Ross).
gen. gobhlain -[æɲ],-[ɛɲ], with lengthening of the stressed vowel the result of compensatory lengthening: < SG gobhal ‘fork’ (EG gaḃul) + the agentive suffix -an.
The identity of Martin’s bird is uncertain. Forbes (1905, 320) cites gawlin as a term for the petrel, and SG gobhlan-mara (with the genitive of muir ‘sea’) ‘Leach’s petrel, Hydrobates leucorhous’ has a forked tail; on the other hand, Martin’s description of the bird as ‘a true prognosticator of fair weather’ suggests SG gobhlan-gaoithe (with the genitive of gaoth ‘wind’) ‘swallow, Hirundo rustica’, with its association with late spring and early summer.
Martin notes that ‘the piper of St Kilda plays the notes which it sings, and hath composed a tune of ʼem ...’, and Forbes (1905, 320) that ‘[a] piper of St Kilda composed a tune on the notes of the gawlin or petrel, which tune is to be found in a volume of poems by the late Rev. Mr MacCallum, Arisaig ...’, cf. the port-à-beul love song ‘Oran Irteach’ (MacCallum 1821, 215–16).