Introduction
The Eastern Bluebird (Sialia sialis) is a familiar sight in open country across eastern North America. Often seen perched on telephone wires or atop nest boxes, these birds are known for their brilliant royal blue plumage in males and the elegant blue tinges in the wings and tail of the grayer females. This article delves into the dietary habits of the Eastern Bluebird, exploring its diverse food sources and how they vary throughout the year.
General Dietary Habits
The Eastern Bluebird's diet consists primarily of insects and berries, with some seeds and wild fruit. The proportion of each varies depending on the season. They feed on a wide variety of insects, including crickets, grasshoppers, beetles, spiders, earthworms, snails, and rarely small lizards or tree frogs. They also consume many berries, especially in winter and wild fruit.
Seasonal Dietary Changes
The amount of insects and fruit taken by bluebirds changes throughout the seasons. Insects comprise up to two-thirds of the diet of an adult Eastern Bluebird during the breeding season. Wild fruits, berries, and seeds comprise the remaining one-third. In the Fall and Winter, bluebirds switch to fruit and berries but still depend on insects. Fruits are essential when insects are scarce in the winter months. During the breeding season, a protein-rich diet is crucial for the growth of their young. When raising young, all species of birds switch to a protein-rich diet.
Foraging Behavior
The Eastern Bluebird's foraging strategy involves scanning the ground from elevated perches and swooping down to catch ground-dwelling insects. Bluebirds hunt for insects by perching on high points such as branches, snags, utility cables, or fenceposts. They catch insects beneath their perches, primarily within a distance of 16 to 65 ft.
Does much foraging by perching low and fluttering down to the ground to catch insects, often hovering to pick up items rather than landing. The Eastern Bluebird also catches some insects in mid-air, and may take some while hovering among foliage. Feeds on berries by perching or making short hovering flights in trees. Most insects and other invertebrates are caught using the “scan-and-swoop-down” method. Bluebirds have remarkable eyesight.
Read also: Dietary Habits of Whip-poor-wills
Nearly 100% of insects taken by eastern bluebirds are on or near the ground. A high proportion of ground-dwelling insects is a result of the bluebird’s foraging strategy.
The Importance of Insects
Insects are a vital part of the Eastern Bluebird's diet, particularly during the breeding season. A protein-rich diet is essential for the growth of their young.
The Role of Berries and Fruit
Bluebirds eat fruit and berries primarily in winter when insects are scarce.
Courtship and Feeding
As a courtship display, the male Eastern Bluebird may sing and flutter in front of the female with his wings and tail partly spread. While perched close together, pairs may preen each other's feathers; the male may feed the female.
Nesting and Parental Care
Nest: Placed in a cavity, typically in a natural hollow in a tree, in an old woodpecker hole, or in a birdhouse. Nests are usually located relatively low (2-20 ft above the ground), occasionally reaching heights of up to 50 ft. Nest in cavity (built mostly by female) is a loosely constructed cup of weeds, twigs, and dry grass, lined with finer grass, sometimes with animal hair or feathers. Incubation is mostly by female, about 13-16 days. Both parents bring food to the nestlings, and young from a previous brood also help to feed them in some cases. Young leave the nest at about 18-19 days on average. 2 broods per year, sometimes 3.
Read also: Red Bat Feeding Habits
Attracting Eastern Bluebirds to Your Backyard
Eastern Bluebirds are a great prospect for nest boxes if you have the space to put one up in your yard, and if your yard isn’t too hemmed in by trees or houses. Consider putting up a nest box to attract a breeding pair. Make sure you put it up well before breeding season. Attach a guard to keep predators from raiding eggs and young.
This species may visit backyards if food is offered. It doesn't often come to feeders, unless you have feeders that provide mealworms.
Mealworms, Bark Butter®, Bark Butter Bits, suet, peanut pieces, sunflower chips, raisins, currants, grapes are some of the food they may eat.
Identification
Male and female are very similar with the female being paler. Plumage is duller in winter. Pale blue, unmarked; sometimes white.
Migration
The Eastern Bluebird is more migratory in its northern range and a non-migratory, year-round resident in its southern range.
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