Summit Outside: Pine grosbeak: An amiable bird

Joanne Stolen
Special to the Daily
Special to the Daily/Joanne Stolen

I saw a pine grosbeak on Miner Joe’s bird feeder in McCulloughs Gulch the other day. This female grosbeak let me get quite close and take pictures. They are widespread throughout the mountains and higher foothills. These large, colorful birds are not often seen by the casual hiker but, once encountered, pine grosbeaks are amiable birds, allowing close approach and observation.

This attractive bird is robin-sized (approximately 8-10 inches in length), and a member of the finch family. The pine grosbeak has a strongly curved black bill. The female has a yellow head and rump and gray back and under sides. The male has a pinkish-red head, breast, back and rump. The back has black streaking. The wings and tail are blackish brown, with white wing bars and edges of the wing.

Some young males have some red or orange feathers in the body plumage, which the females lack. Females on the average are duller in color than males (especially on the crown and rump) and have a lighter russet tinge to the head or lighter olive tinge to the breast than males. Adults have a long forked black tail, black wings with white wing bars and a large bill. The legs and feet of pine grosbeaks are dark brown or black.

The pine grosbeak has an extremely wide distribution, occurring in forests of northern Europe, Russia and North America. In North America, it is found in open coniferous forests, from Alaska to northern New England and southward through the mountains of the West. Like many northern finches, pine grosbeaks wander during the winter months and may turn up almost anywhere across the northern half of the U.S.

Here in Colorado, pine grosbeaks are best found in open forests of pine, fir and spruce, from the high foothills to timberline. It is not known how their welfare and distribution is, or will be affected by the extensive pine-beetle blight that has decimated northern and central regions of our mountainous terrain.

Pine grosbeaks pair off during the breeding season. They make a bulky nest of grasses, rootlets and moss, lined with hair, usually placed low in a coniferous tree not more than 10 feet from the ground. Here the female lays two to five pale, blue-green-blotched eggs. The young fledge in 5-6 weeks and parents have been seen feeding the young after they fledge.

The grosbeak has what is called a “gular” sac in their throat where they store food. This can be used to feed the young. Outside of the nesting season, they often feed in flocks, which can number up to 100 birds.

They have been seen to settle in one tree and feed on one food at length. They eat the buds of many trees, including maple, birch, apple, mountain ash, poplar and willow. Favorite foods include the fruits of crabapple, bittersweet, barberry and mountain ash, and the seeds of birch, pine and spruce trees. In addition, they eat grass and weed seeds and various insects (which make up to 15 percent of their diet in summer).

This grosbeak utters a three-note whistle rendered as “pee-lee-jeh pee-lee-ju.” While foraging in flocks they vocalize with quiet chittering sounds. Its voice is geographically variable, and includes a whistled pui pui pui or chii-vli. The song is a short musical warble.

The pine grosbeak’s short, musical song is reminiscent of the purple finch’s song, but it varies more in pitch and has more distinct, less-slurred notes. The song varies from a clear, loud carol full of trills to a soft, flowing warble. The call sounds somewhat like a greater yellowlegs’s call, consisting of a whistled teu, teu, teu, with the middle note higher. Both call and song may be given during the pine grosbeak’s undulating flight.

Pine grosbeaks may move irregularly southward, in winter, probably in response to reduced food supplies. Some years, few individuals leave the summer range, but other years, whole populations move far south in search of food. In the West, where they may associate with bohemian waxwings, pine grosbeaks may reach Oregon and northwest Idaho, western Nebraska, southwest New Mexico, and northwest Texas. Winter habitat tends to include open mixed and deciduous woods or hillsides with cedar or juniper, and they may visit the edges of cultivated areas where they will take advantage of persistent berries and fruit. Particularly in the western United States, they have been observed taking sunflower seeds from feeders.

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.

Pine grosbeaks have the reputation of being very tame and approachable, especially in winter. They tend to stay hidden within foliage when alarmed, rather than flushing. Their deliberate movements and tendency toward long periods of stationary rest earned them the Newfoundland colloquial name “mope.”

Joanne Stolen is retired from teaching microbiology at Rutgers University.

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