Nature Picks: Things that don't belong

When unusual weather occurrences happen, like snow storms in late May, it can alter the migratory paths of wildlife, and species may be found in places it is uncommon for them to be. Among birds, this is sometimes referred to as an irruption, where one or more species moves south out of their normal ranges in search of food.

As happened in Lincoln this spring, birds may also be seen at lower elevations than their normal ranges. A few varieties of birds that aren't usually found around Lincoln this time of year were spotted during the most recent snow storm.

The first of these was the Baltimore Oriole (Icterus galbula), whose range doesn't generally extend as far west as Lincoln. There are fewer than three recorded observations of Baltimore Orioles in Lewis and Clark County in recent years, and less than twenty at elevations of over 3,000 feet, according to the Montana Field Guide.

Male Baltimore Orioles present with an orange body, a black head, wings, and tail, and a thin white wing stripe. Females may be smaller and have a dark-olive colored head with lighter coloring. The species migrates from southern Mexico, Central America, and northern South America to breeding grounds in northern Montana, parts of Canada, and the Midwest and eastern United States.

Another bird species observed during the snow storm was the Western Tanager (Piranga ludoviciana). While Tanagers summer range covers most of Montana, and they are considered breeding residents in the Lincoln area, peak sitings don't usually occur until June, according to the eBird Occurrence Map from The Cornell Lab of Ornithology.

Western Tanagers are considered song birds, and the male has a yellow body with a bright red head and black wings. Females tend toward olive-green to gray wings with yellowish bodies.

In addition to bird irruptions, there are other examples of plants or animals moving into an area where they are atypical. For plants, these species may be called non-native, introduced, or invasive. Looking toward the west end of the Upper Blackfoot Valley, an uninvited resident is a plant called dodder, which can be seen covering a spruce tree just east of the Helmville turn off Hwy 200. Though it can be difficult to see, the spruce tree is still alive and growing beneath the dodder.

Dodder is identified as a parasitic weed, and there are 100-150 species identified worldwide, according to the article "Five-angled Dodder" by Walter Fertig on the U.S. Forest Service website.

"They consist only of thread-like yellow or orange stems, white flowers, and small round fruits. The mature dodder has no roots or leaves. It is a parasite and is completely dependent on a host plant for its nutrition and water uptake," writes Fertig.

Unlike most plants, dodder do not have chlorophyll. Instead, they obtain all of their nutrients from the host plant and do not rely on photosynthesis. To establish growth on a new host, dodder seeds send out a root and then begin growing twining vines. Once these vines connect with a host plant, the dodder sends out haustoria, tiny tubes that penetrate the host plant to absorb food and water. The dodder root then dies, and the dodder subsists entirely on nutrients taken from the host plant.

Dodder belong to the genus, Cuscuta, and historically belonged to the family Cuscutaceae, writes Fertig. However, due to their similarity to morning glories, some scientists classify them in the family Convolvulaceae instead. Seven species of Dodder are identified in Montana, with two listed as non-native species and the other five listed with undetermined origins in the Montana Field Guide.