Definition of "vernall"

For as a vernall Larke, but lately drest / In her first Downe, abandoning her nest, / Stretchest her pinions, her small force assayes / Flutters, and fals before her flight shee raise, [...]

1633, Thomas Bancroft, The Glvttons Feauer, London: Printed by Iohn Norton, for William Cooke, […]; quoted in “Bancroft, (Thomas.)—The Glvttons Feauer. […] 1633.”, in Thomas Corser, editor, Collectanea Anglo-Poetica: Or, A Bibliographical and Descriptive Catalogue of a Portion of a Collection of Early English Poetry, […] (Remains Historical & Literary Connected with the Palatine Counties of Lancaster and Chester; LII), part I, [Manchester]: Printed for the Chetham Society, 1860, page 139

To my requeſt this anſwer ſhe bequeath'd, / Whiles from her lips the vernall Roſes breath'd; [...]

1640, Ovid, “The Fifth Book; Or, May”, in John Gower, transl., edited by Edward Alliston, Ovids Festivalls, or Romaine Calendar, Translated into English Verse Equinumerally, [Cambridge, Cambridgeshire]: Printed by Roger Daniel, printer to the University of Cambridge; [a]nd are to be sold by M[ichael] S[parke] junior, […], page 107

[...] I have in England for ſome years paſt, kept by me an exact table, or Ephemeris both of the Vernall, and Summer Eteſians; but found the VVinds no leſſe Variable in thoſe Months, then at other Seaſons.

1671, R[alph] Bohun, “[Of the Etesian, or Anniversary VVinds: Their Several Species]”, in A Discourse Concerning the Origine and Properties of VVind. […], Oxford, Oxfordshire: Printed by W. Hall for Tho[mas] Bowman, pages 118–119