Iberian chiffchaff Previously the Iberian chiffchaff was considered as a subspecies of the common chiffchaff. As of 2016, it is recognised as a separate species under the name "Phylloscopus ibericus" for the following reasons (compared to the common chiffchaff): In past, erroneously listed as "Phylloscopus brehmii". Iberian chiffchaff The Iberian chiffchaff ("Phylloscopus ibericus") is a species of leaf warbler endemic to Portugal, Spain and North Africa, west of a line stretching roughly from the western Pyrenees via the mountains of central Spain to the Mediterranean. The name "chiffchaff" is onomatopoeic, referring to the repetitive "chiff-chaff" song of the common chiffchaff ("Phylloscopus collybita").
Genomic evolution of birds possibility of genomic expansion in mammals and reptiles. Also, there is no such genomic loss in any vertebrate group as great as that of birds. Its possible that the early chromosomic fragmentation event that lead to the appearance of microchromosomes in birds significantly contributed to this gene loss. These fragmentation events must have taken place in a common ancestor of most birds, since approximately every two out of three species studied have at least 30 pairs of microchromosomes, 2n = 80 being the size of the average karyotype of birds (with the only exception the family Falconidae, which are 2n