Saturday, March 7, 2015

Rosy-Finch Extravaganza

The recent cold snap that has plunged Laramie back into winter may not be welcomed by most people, but for birders, it is giving us a rare chance to experience the wonders of rosy-finches. In Wyoming, we can see all 3 North American rosy-finch species, as well as another distinct subspecies.  The three species include the Black Rosy-Finch (Leucosticte atrata), Brown-capped Rosy-Finch (Leucosticte australis), and the Gray-crowned Rosy-Finch (Leucosticte tephrocotis), as well as the 'Hepburn's' Rosy-Finch, a distinct subspecies of Gray-crowned. All of these can even be seen in a single flock, especially here in the Laramie area, the only area in the state where you can see our local breeder, the Brown-capped Rosy-Finch.

Black (left), Gray-crowned (center), and Brown-capped Rosy-Finch (right)

Outside of North America, there are 4 additional species of Leucosticte, all inhabiting alpine or tundra habitats. In the past, our North American rosy-finches were lumped with the Asian Rosy-Finch (Leucosticte arctoa) (Macdougall-Shackleton et al. 2000, Johnson 2002), but have since been split on the basis of molecular data and studies of a hybrid zone between Gray-crowned and Black Rosy-Finch (Johnson 2002).

Rosy-finches are famous denizens of the high alpine regions of the Rocky Mountain region, nesting far above treeline in talus slopes and cliff faces, foraging for seeds and insects at the edges of snow fields. Due to the remoteness of their nesting habitat, relatively little is known of the breeding biology of the three rosy-finch species. Each species largely breeds in mountain ranges isolated from the other species, with Brown-capped Rosy-Finches nesting from far northern New Mexico, through much of the alpine of Colorado, and reaching its northern limit in the Snowy Range of Wyoming (Johnson et al. 2000). Black Rosy-Finches are the "middle" rosy-finch, nesting in the Uinta Range of Utah, through the Wind River Range of Wyoming north to the Bitterroots in Montana, and west to central Nevada (Johnson 2002). Finally, Gray-crowned Rosy-Finches are the most widespread species, nesting in Sierra Nevadas in California all the way north to Alaska and the Pribilof Islands. They get as far east as northern Montana, where they occasionally hybridize with Black Rosy-Finches in the Bitterroot Mountains (Macdougall-Shackleton et al. 2000, Johnson 2002).

Rosy-finch habitat - Mount Evans - Clear Creek Co., CO

Even in the winter, rosy-finches can spend a lot of time high in the mountains, sometimes only descending in bad weather to the valleys, foothills, plains, and high deserts of the West (Macdougall-Shackleton et al. 2000, Johnson 2002). Again, Gray-crowned Rosy-finch is the most widespread and frequently encountered species in most places, but in some areas of Utah and New Mexico, Black and Brown-capped Rosy-finches may outnumber them. In Colorado, southeast Wyoming, and northern New Mexico, large mixed flocks containing all 3 species can be found.

Gray-crowned and Black Rosy-Finch flock - Albany Co., WY

Here in southeast Wyoming, Gray-crowned Rosy-Finch is by far the most abundant species, with flocks numbering in the hundreds not uncommon in some places, swirling through the air and raiding bird feeders. Within these Gray-crowned flocks, most represent the "interior" subspecies; up to 10-20% of Gray-crowned Rosy-Finch flocks may be made up of the "coastal," Hepburn's subspecies, characterized by entirely gray cheeks and face as well as crown.

'Hepburn's' Gray-crowned Rosy-Finch - Laramie Co., WY

'Interior' Gray-crowned Rosy-Finch - Laramie Co., WY

'Interior' Gray-crowned Rosy-Finch - Albany Co., WY

In the foothills of the Snowy Range, small numbers of Brown-capped Rosy-Finches can also be encountered amidst the large Gray-crowned flocks. These are often difficult to pick out, as some Brown-capped Rosy-Finches can show fairly extensive gray in the head, best told by the extent and contrast of the gray with the brown on the face and head.

Brown-capped Rosy-Finches - Larimer Co., CO

Brown-capped Rosy-Finch (with Gray-crowned) - Laramie Co., WY

Brown-capped Rosy-Finch - Albany Co., WY

Generally one of the harder species to find locally, Black Rosy-Finches are only occasionally encountered in flocks in southeast Wyoming. Farther west, they are much more common, sometimes being the dominant species along the foothills of the Wind River Range and in the Jackson Hole region. While adult male Black Rosy-Finches are very distinct and easy to identify, females and young birds can be surprisingly tricky. These birds are separated from both Brown-capped and Gray-crowned by the overall "cold" brown and charcoal gray plumage on the body.

Black Rosy-Finch - Albany Co., WY

As winter continues in Wyoming, you can still expect to find rosy-finches close to the mountains, with birds generally returning to their breeding grounds by April when still snow covered. March can be an especially good month to find big mixed flocks of rosy-finches outside of Laramie, as birds from farther south are beginning to return northward. Occasionally, large flocks of rosy-finches can be found coming to feeders around the foothills as late as May when large spring snow storms come through. So, get out there and go see these spectacular birds of the alpine tundra of the West. 

All photos in this post © Shawn Billerman and are not to be used without permission.

References:

Johnson, RE, P Hendricks, DL Pattie and KB Hunter. 2000. Brown-capped Rosy-Finch (Leucosticte australis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/536

Macdougall-Shackleton, SA, RE Johnson and TP Hahn. 2000. Gray-crowned Rosy-Finch (Leucosticte tephrocotis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/559

Johnson, RE. 2002. Black Rosy-Finch (Leucosticte atrata), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/678

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