Orioles are a sweet spring treat

_{|  Story by Meghan McMahon |}

_5/24/2019

Orioles are one of the most anticipated avian arrivals to Will County each spring, and while they’ve been in our area for a few weeks now that hasn’t dampened people’s enthusiasm at catching a glimpse of them.

Will County is home to two orioles species: the well-known Baltimore oriole and the lesser-known orchard oriole. Both have been seen in and around the county for a few weeks now, but their time here will be fleeting, as it is every year.

“They are only here for a very short time,” said Kelli Parke, a former interpretive naturalist at the Forest Preserve’s Four Rivers Environmental Education Center.

The orioles are typically seen in Will County from mid- to late May until July, Parke said. After that time, they begin their migration south, returning to wintering grounds in Florida, the Caribbean and Central and South America, according to the Cornell Lab of Ornithology. They are among the first birds to begin their migration south each year.

Here’s a closer look at both oriole species, as well as their similarities and differences.

Appearance and plumage

Both the Baltimore oriole and the orchard oriole are known for their trademark plumage, but it’s only the males of the species that display these striking colors.

Male Baltimores have the signature black heads and backs with bright orange breasts and tail feathers. The females are more drab in color, with their breasts ranging from shades of yellow, to orange or brown with gray heads and backs.

The male orchard orioles swap the brilliant orange the Baltimore orioles sport for a reddish or maroon-colored breast, but still have black heads and backs. Female orchard orioles have yellowish-green plumage with no black feathers, but their wings are brownish in color.

The Baltimore orioles are the bigger of the two birds, and are slightly smaller than a robin. In contrast, orchard orioles are considerably smaller than Baltimores. Both species, however, have straight, sharp bills well-suited for foraging for insects.     

Habitat

Both of these orioles prefer habitat ranging from open woodland habitats to deep, forested areas, the Cornell Lab reports. Orchard orioles are often seen near water, including riverbanks and lakeshores. Baltimore orioles also frequent areas near rivers, but also forest edges and smaller groves of trees.  

While the Baltimores prefer high treetops, making them a little more difficult to spot, the orchard orioles are typically lower down on tree branches, Parke said. 

Among Will County forest preserves, McKinley Woods – Kerry Sheridan Grove is one of the best locations for spotting orioles, because of its proximity to water, she said. 

Diet

Both Baltimore and orchard orioles eat insects, fruit and nectar, but to varying degrees. Their diets also tend to vary by season.

Orchard orioles eat primarily insects and arthropods, consuming fruit and nectar to a lesser extent. Their diet changes as they prepare for their migration south, switching to eating primarily fruit, according to the Cornell Lab. Baltimore orioles eat mainly insects during the summer breeding season, while relying on nectar and fruit more in the spring and fall because the sugar content is easily turned into fat, which they can use for energy while migrating.

Both kinds of orioles are often seen in backyards and at feeders. Baltimore orioles like ripe fruit and can be attracted to your yard simply by cutting oranges in half and hanging them from trees or planters. They also eat nectar and can be attracted by leaving out jelly, particularly grape jelly. You can even buy special feeders made to hold the oranges and jelly. The orchard orioles will also eat the oranges and jelly but may also be seen eating nectar from hummingbird feeders. And in the fall, when their diet switches to fruit, they may pay a visit if your yard has fruits such as mulberries and chokecherries. 

Nesting

Both types of orioles build impressive, sock-like nests out of grasses and other plant fibers. Baltimore orioles tend to build nests high up in the trees, while orchard orioles build their nests at varying heights above ground, the Cornell Lab reports.

The female orioles build their nests, weaving together the fibers for about a week until they are complete. Baltimore orioles build in three phases, starting with the outer structure, then creating a bowl inside the nest before lining the bottom with downy feathers. Orchard orioles also line the bottoms of their nests, but you can often see the eggs through the nest when standing below.

 

The orioles are not particular about nesting materials, using any long, stringy materials they can find, whether its plant material or not, Parke said. In fact, Four Rivers has an oriole nest that is made entirely of plastic, weaved together from items such as fishing line, floss and plastic grasses like we use to fill Easter baskets.

Baltimore orioles often build their nests in elm trees, but also nest in cottonwood and maple trees, according to the Cornell Lab. Orchard orioles are less particular about their nesting locations, building nests in a wide variety of trees, including ash, cottonwood, elm, magnolia, maple, oak, pecan and spruce trees.

Conservation status

Both Baltimore and orchard orioles are fairly common, but their populations are declining, although neither is listed on the 2014 State of the Birds Watch List. 

The worldwide breeding population of Baltimore orioles is estimated at about 12 million, with the vast majority spending at least part of the year in the United States, according to the Cornell Lab. These orioles are vulnerable to deforestation and habitat loss, and they are also affected by insecticide use, which can both limit their food supply and also possibly harm the birds directly. 

Orchard orioles are not as numerous as the Baltimores. With an estimated worldwide breeding population of 10 million, the majority spend time in the United States each year. The population of these orioles tends to decline as a result of animal grazing, which destroys shrubs and can affect the flow of water near their habitat, the Cornell Lab reports.

 

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