These Little Brown Bird Wren T-shirts were a custom design by Liz Toole on Anglesey. Based on a lino carving and screen printed by Perris & Corr in Penygroes. 
They are a natural cotton/calico colour in unisex sizes:
XS - 48cm pit to pit
SMALL - 50cm pit to pit
MEDIUM - 55cm pit to pit
LARGE - 57cm pit to pit
(I’m usually a 6/8 and pictured wearing an XS)