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Publishing history:
v1.0: 01/10/24
v1.1: 15/06/25
goillir m. *[ˈɡ̊əʎ̪ɛɾʲ], gen. idem, and goillire *[ˈɡ̊əʎ̪əɾʲə] 
Cf. [gö2lly’´-ur-a] (McAlpine 1832).
‘A little bigger than a sparrow it appears all black with a white rump. Its tail is not forked, unlike Leach’s petrel. In flight it flutters over the water, feeding with its wings held up in a ‘V’ with feet pattering across the waves. At sea it often feeds in flocks and will follow in the wake of ships, especially trawlers. The storm petrel breeds largely on islands on the west coast of the UK and on the Northern Isles. Only comes to shore to breed and then at night. Best looked for by seawatching in spring and autumn from a westerly headland with onshore gales.’ (RSPB˄.)
I.e. malefices ‘acts of baleful or malefic socery’ (DOST˄, s.v. malefice).
In his Sailor’s Word-Book (1867), Smyth lists both goylir ‘a small sea-bird held to precede a storm; hence seamen call them malifiges; arctic gull’ (after Martin) and goillear ‘the Gaelic for a sea-bird of the Hebrides, said to come ashore only in January’ (possibly a miscopying of Armstrong, whose own entry goillir follows his entry goillear).
SG goillir is derived by Henderson (1910, 128–29) from ON kolr ‘coal-black’, but no such word is attested, as Lockwood (1971, 26–27) points out.
McDonald at first considers the loan likely (2009, 376), later unlikely (2015a, 126).
Martin’s (ibid., 71–73) list of bird names includes both Scots words: ‘the bird corn craker’ (cf. Scots corn-craik, Eng. corn crake), ‘the colk’ (= Eider-duck) and ‘the rain-goose’ (= red-throated diver), and Scots forms of Gaelic words: ‘the gawlin’ (q.v.), ‘the bonnivochil’ (SG buna-bhuachaill, q.v.), ‘the bird screachan-aittin’ (SG ?sgreuchan-aitinn ‘juniper-screecher’, unidentified) and ‘the bird faskidar’ (SG fasgadair (= skua)). Martin’s goylir is assumed to be a Scots form of SG goillir (SND˄), 
Jamieson’s (1808) headword goyler is his own (Scots) rendition of Martin’s goylir.
However, if we can assume that Martin’s gawlin (recte gowlin, which occurs twice in his contents list) is a Scots form of SG gobhlan (< gobhal ‘fork’ + the nominally diminutive suffix -an), implying Scots /ʌu/ for SG /ɔu/ (if not Scots /uː/ for SG /oː/), perhaps we can assume that Martin’s goylir implies Scots /oɪ/ for SG /ɔi/ (/əi/) and that we should perhaps read SG *goibhleir *[ˈɡ̊ɔilɛɾʲ], *[ˈɡ̊əilɛɾʲ], which might also be a derivative of SG gobhal, but with the agentive suffix -eir (-air), with medial palatalisation (cf. SG gobhal ‘fork’, (pl.) goibhlean; sabhal ‘barn’, (pl.) sabhalan, saibhlean; sràbh ‘straw’, (diminutive and singulative) sràibhlean), 
Indeed, Jamieson (1808) derives Scots goyler (sic) from SG godhler, gobhler (sic).
An alternative name for the storm petrel in Gaelic is gur-le-gùg (Dwelly 1911: ‘hatch with song’; Forbes 1905, 320: gur-le-gug), which is probably the folk etymologised equivalent of guile-gùg ‘storm petrel’ (AFB˄: /gulə guːg/), perhaps imitative of the storm petrel’s chattering, purring call (RSPB˄)’, itself probably a variant of the onomatopoeic word gurra-gùg ‘cooing’. (Dwelly, however, associates gur-le-gùg with ‘the kind of cooing uttered during hatching-time by the small sea-fowls called Mother Cary’s chickens [= storm petrels]’.
In summary, while the form SG goillir has been perseverated through a number of lexicographical works, it is Armstrong’s (1825) own interpretation of Martin’s goylir, but Martin’s form seems more likely to be a Scots representation of an otherwise unattested SG *goibhleir *[ˈɡ̊ɔilɛɾʲ], *[ˈɡ̊əilɛɾʲ] in the sense ‘fork-winged bird’, with reference to the particular wing shape of the storm petrel while feeding in flight.