Siberian chiffchaff to be a full species due to its distinctive plumage and vocalisations, being similar to "P. s. sindianus" in these respects. Common chiffchaffs (of the nominate race) and Siberian chiffchaffs do not recognize each other's songs. Pending resolution of the status of the form "fulvescens", which is found where the ranges of common chiffchaff (of the race "abietinus") and Siberian chiffchaff connect and may or may not be a hybrid between these, "tristis" is maintained in "P. collybita" by most checklists. Siberian chiffchaff Siberian chiffchaff ("Phylloscopus (collybita) tristis") is a leaf-warbler which is usually considered a subspecies of the common
The Sibley Guide to Birds The Sibley Guide to Birds The Sibley Guide to Birds is a reference work and field guide for the birds found in the continental United States and Canada. It is written and illustrated by ornithologist David Allen Sibley. The book provides details on 810 species of birds, with information about identification, life history, vocalizations, and geographic distribution. It contains several paintings of each species, and is critically acclaimed for including images of each bird in flight. Two regional field guides using the same material as "The Sibley Guide to Birds" were released in 2003, one for the western half of