Friday, December 11, 2009

Gray-crowned Rosy-Finch

The Gray-crowned Rosy-Finch is another lover of extreme habit found in open ground at the top of mountains from Alaska to California and out on the Aleutian and Pribilof islands. The Gray-crowned is found farther to the west than the similar Brown-capped and the Black Rosy-Finch. It prefers open rocky hillsides, often near cliffs and, like the other Rosies, winters at lower elevations.
These are possibly the highest-altitude breeding bird in North America. Perhaps because of these remote breeding sites, which allow little contact with humans, the Gray-crowned Rosy-Finch seems almost tame. On breeding grounds, foraging birds can be approached to within a foot or two. Even after banding, individuals often alight less than three feet away, picking at their new bands and preening for several minutes.

The Gray-crowned Rosy-Finch is most likely to be confused with other rosy-finches, but the Black is much darker and lacks brown back and breast and the Brown-capped lacks gray on head. To identify, remember it has a brown body, extensive pink on shoulders, flanks and belly, a dark brown forehead with grey behind which wraps around the head.

Juveniles similar to adult females, but duller coloration, and lacking gray crown, black forehead, and pink on under parts. Size and color vary geographically.

There are six subspecies of the Gray-crowned Rosy-Finch. These subspecies comprise two basic forms: a larger coastal form that lives on the vast treeless plain in the Arctic regions where the subsoil is permanently frozen and a smaller alpine-interior form that lives in the high mountains above tree-line. Additionally, the six can be separated into three gray-cheeked and three brown-cheeked forms.

The gray-cheeked forms are very large; nearly twice as large as others and are characterized by their gray cheeks. These breed in the Pribilof and Aleutian Islands, as well as montane regions from west-central Alaska east to south-west Yukon and south through the Cascades to north-central California. Some move south and east, occasionally long distances, in fall and winter; from the southern part of the breading range and as far as central New Mexico. These three are the:

• Aleutian Rosy-Finch
• Pribilof Rosy-Finch, and
• Hepburn’s Rosy-Finch which winters in southern part of breeding range, east to central Montana, west Nevada, northern Utah, and central New Mexico. Substantially smaller, with shorter bill, than other gray-cheeked forms its gray and black throat contrasts sharply with dusky brown breast.

The brown-cheeked forms are characterized by brown auriculars (the feathers over the ears) that contrast with gray hindcrown. These are found mostly in interior mountains from the northern Rocky Mountains and south to Wallowa Mountains and the Sierra Nevada’s. The three are the:

• Gray-crowned or Cassin’s Gray-crowned Rosy-Finch, which breeds in interior mountains of Alaska, British Columbia, and Montana and winters from southern British Columbia, east to southwest Manitoba and south to northeast California, Nevada, Utah, northern New Mexico.
• Wallowa Rosy-Finch breeds in the mountains of north-east Oregon; winters south to west central Nevada, and the
• Sierra Nevada Rosy-Finch; resident in the Sierra Nevada and White Mountains of California.

Generally these birds are found in alpine areas, usually near snow fields or glaciers, talus, rock-piles, and cliffs; typically at or above timberline. It winters in open country, including mountain meadows, shrub-lands, roadsides, towns, cultivated areas, and rocky hillsides.

Food for the Gray-crowned Rosy is similar to other Rosies and includes seeds, insects and some vegetation. That said, there is considerable variation in diet depending on habitat:

• Pribilof Rosy-Finch in summer, predominantly eats crowberry seeds but also often takes brook and sea parsley seeds. Other seeds include rush, sedge, chickweed, buttercup, cinquefoil, and bluebell. Insects taken include crane flies, ground beetles, leaf beetles, beach beetles and weevils. In winter, this bird is observed to eat almost exclusively wild parsnip.
• Aleutian Rosy-Finch eats adult beetles and their larva, as well as leaves, buds and seeds of Scurvy-grass.
• Hepburn’s Rosy-Finch eats almost exclusively seeds; Russian, wild grass, mustard, and sunflower.
• Gray-crowned Rosy-Finch eats seeds of Whitlow grass, willow-weed, spring beauty and bear grass; in breeding season, insects include cutworms.
• Sierra Nevada Rosy-Finch eats seeds of sedge, sticky cinquefoil, oval-leaved buckwheat, and cut-leaved daisy. Insects eaten include gnats, cutworms, pine needle scale (taken from white-bark pines) and mayflies.

Like other Rosies, the Gray-crowned habitat includes western mountains often close to 10,000’ in nests similar to others. The winter range includes resident breeding areas, but also disperses to lower elevations of mountains (mainly lower slopes and valleys), coastal areas of the Pacific Northwest and casually south and east of Rocky Mountains and Sierra Nevada’s.

Winter flocks also occur east of Cascades in Washington and Oregon, throughout Idaho, Montana, Wyoming, Nevada, Utah, the western half of Colorado, mountains of north-central New Mexico, and in the Black Hills and Badlands of southwest South Dakota and extreme northwest Nebraska. In California, also winters in valleys east of breeding range in Sierra Nevada crest, on lower slopes of White, Inyo and in Marble Mountains. At this time it generally it prefers open country …wherever bare ground is found and food is available. Flocks usually land on ground, sometimes on buildings, occasionally in trees or bushes, fences, telephone wires and may congregate at feeders if snow covers food or natural food is scarce.

This beautiful shot contributed by Bill Maynard,
editor of the American Bird Conservancy's publication "Winging It"
Notice that the Hepburn's head is entirely gray.

The conservation rating for the Gray-crowned Rosy-Finch is Least Concern.

The Sibley Field Guide to Birds of Western North America – David Allen Sibley
Smithsonian Field Guide to the Birds of North America – Ted Floyd
Western Birds – Roger Tory Peterson
Birds of North America-Online from Cornell Lab of Ornithology - Field Guide to Birds of North America – also from Cornell Lab of Ornithology - Science for a Changing World

This is the fourth and final piece on Rosy-Finches. First photo is from Wikimedia; the last one by Bill Maynard who showed me that the Hepburn's entire head is you can see in his lovely photograph.

1 comment:

scienceguy288 said...

I have learned much about these pretty birds in your series! Thanks!