Hi everyone
In our ringing sessions in Parque Biológico de Gaia (Portugal) we've caught a very strange female Great Tit (Parus major). Please see the photos:
http://anilhagemdeaves.weebly.com/parusmajor.html
The bird looks pale all around. I've searched for an answer, but it doesn't seem to fit the established colour aberrations. I've read Hein van Grouw's excellent and thourough article (see here: http://www.vogelringschier.nl/DB28%282%2979-89_2006.pdf), but nothing seems to match. The first thing that one notices in the bird is some of the black feathers are whitish, which is to be expected in a leucistic bird. However, according to Grouw, cases where individual feathers are partially discolored are rare, and you can see that clearly in the tail feathers.
I'd go with the bird having a rare type of leucism, but what about the white patches in blue and green feathers in the wing and back? These colours are not produced by pigments... surely the bird shouldn't have two colour disorders caused by two unrelated problems. Unfortunatelly I forgot to take a good shot at the yellow belly, but I recall the bird also being pale there!
Any help would be greatly appreciated!
In our ringing sessions in Parque Biológico de Gaia (Portugal) we've caught a very strange female Great Tit (Parus major). Please see the photos:
http://anilhagemdeaves.weebly.com/parusmajor.html
The bird looks pale all around. I've searched for an answer, but it doesn't seem to fit the established colour aberrations. I've read Hein van Grouw's excellent and thourough article (see here: http://www.vogelringschier.nl/DB28%282%2979-89_2006.pdf), but nothing seems to match. The first thing that one notices in the bird is some of the black feathers are whitish, which is to be expected in a leucistic bird. However, according to Grouw, cases where individual feathers are partially discolored are rare, and you can see that clearly in the tail feathers.
I'd go with the bird having a rare type of leucism, but what about the white patches in blue and green feathers in the wing and back? These colours are not produced by pigments... surely the bird shouldn't have two colour disorders caused by two unrelated problems. Unfortunatelly I forgot to take a good shot at the yellow belly, but I recall the bird also being pale there!
Any help would be greatly appreciated!
