Xenornis

On May 5, Matías Díaz found a weird Variable Seedeater with a lot of chestnut on the collar and underparts while birding in a yard in Portobelo. Although it was assumed to be a weird bird moulting from juvenile plumage, or that had taken a bath in a muddy puddle, further research produced Hosner & Lebbin's 2006 paper Plumaje aberrations in Ecuadorian birds that illustrates a similar Variable Seedeater seen in Ecuador in 2005 and references a similar specimen from Panama: The Sporophila corvina observed at Buenaventura appeared to exhibit erythromelanism, where erythro - melanin was deposited in normally white contour feathers. Olson (1966) collected a Sporophila corvina in Panama (AMNH) that exhibited similar plumage features to the individual observed at Buenaventura, with chestnut replacing the white contour feathers except the midbelly. Like the individual at Buenaventura, in Olson’s specimen the wing speculum and axillaries remained white. Erythro - melani...

Variable seedeaters are common round our house (Palmilla, Mariato district, Veraguas Province), but in the last week of may we found some that were rather more variable than normal. As the attached photographs show, the chin and neck of the bird are not white, but quite bright yellow. We have never seen this variation before and Vencicioo Wilson, who does quite a lot of birdwatching, was also at a loss and said he had never seen variable seedeaters like this. Bill Adsett chimes in: In fact it’s not that unusual to see Variable Seedeaters with yellow neck bands (or whatever the correct technical name is). It’s not something confined to Azuero. I have seen this coloration on a few birds at different times at Altos de Cerro Azul and in Panama City. I have no idea what the explanation is!