Reflections in Nature: ID of bird nest builders tricky

Recently, a young man stopped by our house with an abandoned bird’s nest that he found. He was curious as to what species built the nest and asked if I knew.

Being unable to identify the builder of the nest, I told him that I would try to find out. After going through several books, I found that identifying a bird’s nest can be very tricky since many species of birds build similar nests.

While most of us are able to identify the nests of a robin and a wren, it becomes much harder; however, after searching through more books and other sources, I finally came to the conclusion that the nest was built by a red-eyed vireo. This conclusion was made after identifying the location where the nest was built, materials used in construction and also the shape and size of the nest.

The red-eyed vireo builds a dainty little pensile nest, also known as a hanging or suspended nest, similar to that of the Baltimore oriole.

The nest, which is suspended from a forked tree branch, is made of fine grasses, bits of bark, pine needles and paper from a wasp’s nest. Bits of lichen sometimes are attached on the outside of the nest.

The red-eyed vireos’s scientific name is Vireo olivaceus.

Vireo is Latin and means a kind of bird, believing to come from the green finch virere, meaning to be green. The species name olivaceus is Latin and means olive-colored; green obscured, with a natural tint.

The red-eyed vireo is about 5 to 6 inches long, with a wingspan of 9 to 10 inches; olive to a greenish on its upper body, with white underparts; a gray cap, with a white stripe over ruby-red eyes and a black stripe through the eye.

In most vireos, the sexes are outwardly similar or nearly so, without a seasonal change in plumage.

The red-eyed vireo is one of the most common birds in Pennsylvania and perhaps the most numerous and widespread woodland-nesting species in the state.

However, it is heard more often than seen. The red-eyed vireo is a persistent singer during the breeding season, uttering an endless series of short phrases from dawn till dusk, even on the hottest days when other birds are silent.

Their persistent song is legendary. One red-eyed vireo was once heard to sing 22,197 songs during a single day. The calls are compared to an evangelist, with phrases such as “you-see-it,” “you-know-it,” “do-you-hear-me” and “do-you-believe-me?”

This vireo also is one of the most abundant birds in North America; however, its numbers seem to have declined recently, possibly as a result of either the destruction of wintering habitat in the neo-tropics, fragmentation of northern breeding forests or other causes.

Its principal habitat of broad-leaved forests often supports one pair per acre.

The red-eyed vireo, which winters in South America, begins appearing here in our state during late April through the second week of May.

After the female builds the cup nest, three to five eggs are laid. Both the male and the female feed the young, which will leave the nest after about 12 days.

The red-eyed vireo is a common host to the brown-headed cowbird. Possibly no other species is victimized more in the number of nests parasitized.

Local family groups will begin wandering about during late July. By late August, the number of birds flocking together will indicate that migration has begun. The greatest number of red-eyed vireos are seen during September as the migration reaches its peak.

Collecting objects from the outdoors is a natural habit. Who among us, as a child, didn’t come home with a pocket full of rocks, a flower or perhaps or a feather? Even as adults we eagerly pick up nature’s little treasures when they come our way.

While in today’s world it is probably safe to say that the greater majority of feathers and abandoned nests that are brought into the home are honest finds, there are two federal laws – the Lacey Act of 1900 and the Migratory Bird Treaty Act of 1918 – that pertain to possessing feathers and abandoned birds’ nests.

The nest brought in to me was given to Nicole Harris, the naturalist at Mt. Pisgah State Park, who has an educational permit that allows her to legally have the nest.

Bower retired after 34 years as a wildlife conservation officer for the state Game Commission. He has published several books about his experiences. Questions and comments may be sent to him at 153 Redington Ave., Troy PA 16947.