The Evening Grosbeak (Hesperiphona vespertina) belongs to the family Fringillidae, which contains 235 species including the American goldfinch and Pine Siskin. Their closest relative is the Hooded Grosbeak from Mexico and Central America.
These large stocky finches have a thick neck, with a large conical shaped bill, large body, short legs and a short tail. Males have a chocolaty-brown colored head and neck, a bright yellow forehead and stripe over their eye and their bills is a light ivory color. Their body is a muddy yellow with black wings and white wing patch, and their tail is short and black. Females are mostly olive-brown, have gray underparts with some yellowish highlights on their neck, a yellowish green bill, with black and white wings along with a short black tail. They are one of the larger finch species with a wingspan of 11.8-14.2 inches and weighing 1.9-2.6 oz, which is a bit lighter than a deck of cards.
The Evening Grosbeak is a very social bird and is often seen in groups, during the breeding season they may split up into pairs or just small groups, but during the winter months, they may form large foraging flocks. Like many finch species, they have an undulating flight pattern, same as you would see in the smaller American Goldfinch.
This colorful songbird doesn’t actually have a song, but instead communicates using simple calls and chirps. There are actually five different recognised call groups. Each call type is specific to their own ranges. The type 3 is the one you would see or hear in the eastern half of North America, they are also the most irruptive of the five groups, where the other four tend to be more residential. The Evening Grosbeak got its name from Henry Schoolcraft, who collected the first specimen; he believed that they called only in the evenings.
Before the 1800’s, the Evening Grosbeak were rarely seen east of the Rockies. Around this time though, ornamental Box elder trees were becoming more prevalent in cities in the east, creating a new food source, since then, they have become a much more regular migrant in the east. This new food source and the increase in backyard bird feeders are believed to be the main factors aiding in their eastward expansion.
Evening Grosbeaks are considered irruptive migrants, meaning that depending on several factors influence how many and how far they migrate. Typically these irruptions are dictated on the abundance, or lack of, seed crops. Years where these seed crop yields are low, are the years that the evening grosbeak, as well as other boreal finches, travel the farthest south in search of food. Although in years where the food is plentiful, they may stay in their typical breeding range and not travel far.
Their diet varies depending on the time of year. During the summer and breeding season, their diet consists mostly of invertebrates, including spruce budworms, caterpillars, beetles and aphids. In addition, seeds from species such as maples, box elder, apple, pine, and cherry are included. Fruits are also part of their summer diet, especially fruit from crabapples, hawthorn, russian olive and juniper. They typically prefer to forage for food at the top of trees but will go lower to feed on fallen fruit and to catch insects. Their large bills allow them to crack and eat larger seeds than most other finch species are able to.
The Evening Grosbeak breeds in mature coniferous forests of the northernmost regions of North America and the Rocky Mountains. During the rest of the year, this bright grosbeak lives in coniferous and deciduous forests.
During the breeding season, their breeding range extends across Canada through the western mountains of the United States to Mexico. Nest construction typically begins in mid-May to early June and is constructed high in a tree or shrub, usually on a horizontal branch or in the fork of a tree. Often the chosen tree is deciduous, either a species of spruce or pine. While it is not known whether the male or female chooses the nest site, the female is the one who collects most of the materials and builds the nest. The saucer-shaped nest, which measures about five inches wide, consists of small twigs while the inside is lined with grasses, lichens, moss and pine needles. Inside the nest, two to five light-blue with brown splotched eggs that are about .92 inches long will be laid. In about 12-14 days these eggs will hatch. Like other songbirds, their young are altricial and hatch with their eyes closed and only covered in small white down feathers. After 13-14 days, they will fledge. They can have one to two broods of young a year.
Unfortunately, the Evening Grosbeak is classified as vulnerable. It is estimated that their population has dropped approximately 92% since the 1970’s. Though due to their irruptive patterns, it is hard to precisely estimate their population size.
This irruptive pattern along with their secretive nesting habits, means they are difficult to study resulting in a lack of data. Because of this lack of data and its steep decline, research is being done to help find the exact cause of this decline. Organizations such as have developed a program to begin color banding and attaching transmitters to individuals to collect the data needed to develop a conservation plan to stop the decline and hopefully reverse the downward trend.
Some of the reasons that are currently believed to be the main cause of this decline are habitat loss from logging of boreal forests, disease outbreaks such as West Nile Virus and conjunctivitis, window and vehicle collisions, effects from climate change and possibly from the reduced numbers of spruce budworms and other insects from aerial spraying.
Hopefully with further study, the exact cause of this decline can be pinpointed and a plan created and implemented to help this beautiful boreal finch rebound.
Further reading:
Finch Research Network: https://finchnetwork.org
Powdermill Avian Research: https://powdermillarc.org
Road 2 Recovery: https://r2rbirds.org
Live video Maine
References:
I live in Ashland, Wisconsin, saw a female evening Grosbeak having lunch in feeder at 12:30 p.m.