Pine Grosbeak - Systematics and Evolution

Systematics and Evolution

The Pine Grosbeak, together with its Himalayan relative the Crimson-browed Finch (P. subhimachala), represents an ancient divergence from the same stock that also gave rise to the true bullfinches (Pyrrhula). The Pinicola lineage diverged from its relatives perhaps a dozen million years ago, during the Clarendonian faunal stage of the mid-Miocene.

At the same time, the evolutionary radiation of Pyrrhula throughout Eurasia and the Holarctic expansion of the closely related Leucosticte mountain finches and relatives began. These genera evolved in the interior of Asia, and thus the original Pinicola stock was probably already a conifer forest bird living to the north of the Himalayas. The separation of the modern species is likely the result of climate change which displaced Pinicola habitat to subarctic northern and subalpine Himalayan regions. Possibly, the ancestors of the North American Pine Grosbeaks were wind-blown individuals which arrived via the northern Pacific, as the Bering Land Bridge was generally submerged in the Late Miocene.

According to studies by Arnaiz-Villena et al., all birds belonging to the genus Pyrrhula have a common ancestor: Pinicola enucleator.