There are a few introduction schemes going on across Britain in the 21st century that the picture is getting clouded regarding genuine immigrants from abroad.
1). 1909 Gugh, shot, 11th November, photo, now at Isles of Scilly Museum.
("F.W.F." Field 18th Dec., 1909: 1100; Eds., British Birds 3: 341; Penhallurick, 1978; Flood, Hudson & Thomas, 2007: plate 33).
2). 1924 Tresco and St Helens, seen, November.
(H. W. Robinson, British Birds 19: 287; Penhallurick, 1978).
3). 1947 Various islands, adult, seen, April to 21st December; same as Cornwall.
(B. H. Ryves & H. M. Quick, Cornwall Bird Watching & Preservation Society Report 1947: 37, 40; Penhallurick, 1978).