There's a Bluebird on my Shoulder...Perched high on a wire leading to a friend's home, I recall the first time I saw an Eastern Bluebird's distinctive bright blue plummage (with reddish brown throat and breast and white belly. Adult females, which I didn't see that day, have lighter blue wings and tail, a brownish throat and breast and a grey crown and back.)
We watched it from inside. Soon it fluttered close to the ground, caught some presumably scrumptious morsel, then brought it to his nesting box.
My friend had thoughtfully installed this box at the top of a slope on her property overlooking her flower garden and lawn at the edge of a wooded area. How exciting it was to know that this little bird was bringing food to a growing brood of Eastern Bluebirds (Sialia sialis). Often seen in open woodlands, farmlands and orchards, these medium-sized thrush are also known to visit some suburban areas.
Though my first encounter with bluebirds occurred years ago, I still recall feeling almost parental in my concern for this young family. Especially once she told me about their struggles to survive amidst the triple threat of aggressive non-native species, habitat destruction, and pesticide use.
Nay, I'll have a starling ... (William Shakespeare from the play Henry IV)
Two of the non-native species that my friend spoke of are the aggressive House Wren and European Starlings. Both of these compete with bluebirds for nesting spots in woodpecker holes and in natural cavities in dead trees. Especially Starlings who can't fit through the small holes of nesting boxes, but will drive timid Bluebirds out of abandoned woodpecker holes and other natural nesting spots. Unbelievably, according to the National Agricultural Library, European Starlings were introduced as part of a plan to bring to the United States all of the birds mentioned in the works of Shakespeare.
Although male Bluebirds will attack other species that threaten them (including Tree Swallows, Great Crested Flycatchers, Carolina Chickadees, and Brown-headed Nuthatches, Robins, Blue Jays, mockingbirds, and cowbirds), they are no match for House Sparrows. House Sparrows are also known as Old World Weaver Finches and House Sparrows not only take over bluebird nests, but will kill adult bluebirds and even smash their eggs. They were introduced as a means of pest control in the 1800's. They have adapted, thrived, and multiplied. These deceptively cute, little song birds, are one of this continent's most common birds with numbers nationwide over 150 million! For this reason, only install a Bluebird box if you are able to monitor it for Sparrows.
Provide Nesting Boxes
Bluebird boxes need to be checked at least once a week during the nesting season. Once you see young in the box, check on them until the chicks reach two weeks old. At that point you might cause them to fledge before they are ready to fly. The male Sparrow constructs a bulky, dome-shaped nest of coarse grasses, weeds, hair, and feathers, which is easy to distinguish from Bluebird nests are cup-shaped and woven of grass with possibly pine needles. House sparrow nests need to be removed immediately, before their young hatch.
To help the bluebirds, many concerned birders provide a nesting box with a hole small enough to exclude European Starlings, and lacking a perch, which attract House Wrens and Sparrows. Luckily, enough people have provided Bluebirds with nesting boxes, monitored and cleaned them, that Bluebirds no longer need protection under the U.S. Endangered Species Act.
In addition to placing a single nesting box, you can create a nesting site by starting a bluebird trail. A bluebird trail is a series of bluebird boxes placed along a prescribed route. By mid-March bluebirds begin looking for nesting sites; however, bluebird houses may be put up later in the nesting season since Bluebirds usually have more than one brood per season.Did you know:
Male Eastern Bluebirds will challenge each other for territory. They put on quite a show of high-speed chases, foot-to-foot combat, plucking at their opponents' feathers with their beaks, and even slapping each other with their flapping wings.
To attract his mate, the male Eastern Bluebird puts on a show of carrying nesting materials into then out of his nest hole, and perching nearby to gesture with his wings. A female accepts his proposal by entering the nest hole. Once they bond, they may stay together for several seasons. Despite his show, the female Eastern Bluebird actually constructs the nest then incubates her brood.
The range of Eastern Bluebirds reaches from Southern Canada, down eastern North America and south as far as Nicaragua. Birds that live farther north and in the west of the range tend to lay more eggs than eastern and southern birds. Not surprisingly, Eastern Bluebirds are found east of the Rockies. Their vast range stretches from southern Canada to the Gulf States and further southwest to Nicaragua.
For those of you fluent in the language of bird calls (according to Sibley, 2000), the male Eastern Bluebird's call "includes sometimes soft warbles of jeew or chir-wi or the melodious song chiti WEEW wewidoo".
What's in Season?
To find the insects and other invertebrates that make up two-thirds of an Eastern Bluebird's warm-weather diet, they gain their bird's-eye-view by perching on branches or fences overlooking open areas. Their excellent eyesight allows them to spot their prey up to sixty feet away.
Bluebirds favor beetles, caterpillars, centipedes, crickets, earthworms, grasshoppers, katydids, millipedes, spiders, and even snails. Surprisingly, these little birdies also enjoy creatures such as lizards, salamanders, shrews, snakes, and tree frogs.
As the weather cools and insects become scarce, Bluebirds adjust by eating large amounts of native fruits and berries.
To Migrate or Not to Migrate...
If they can find enough food to eat, Bluebirds won't migrate. They will stay in a group and seek cover in heavy thickets, orchards, or other places where they can find cover and food.
A Nest by any other name...
A nestful of Bluebird eggs may contain from 4 to 7 light blue eggs. A small percentage of their eggs may be white. The incubation period for bluebird eggs is 12 to 14 days. Nestlings remain in the nest 18 to 21 days before they fledge.
Clean out the nesting box of nests, whether bluebirds or those of other birds, as soon as the young birds have fledged. Eastern Bluebirds typically have more than one successful brood per year. Young produced in early nests usually leave their parents in summer, but young from later nests frequently stay with their parents over the winter.
Many birders keep records of the activity on their bluebird trails.
Location, Location, Location
Eastern Bluebirds live in open country around trees, but with little understory and sparse ground cover. Original habitats probably included open, frequently burned pine savannas, beaver ponds, mature but open woods, and forest openings. Today, they're most common along pastures, agricultural fields, suburban parks, backyards, and golf courses.
If you are looking for a great spot for your Bluebird nesting box, an ideal spot mimics the areas just mentioned. Areas with sparse ground cover in an open rural setting is best. Avoid brushy and heavily wooded areas where House Wrens are numerous. Avoid areas near homes and buildings which is where House Sparrows are more abundant. Also avoid areas where pesticide is used.
It may take Bluebirds a few seasons to find new nesting boxes, especially if they aren't common in your area, since they normally stay in the same vacinity.
Bluebird AssociationsWherefore art thou Bluebirds?
While researching these adorable birds, I came across EBIRD.com, a website where you can view where bluebirds and other birds have been spotted. As fellow bird lovers, we can submit our own birding observations. To add your sightings sign up, then enter when and where you went birding, then check which birds were seen and heard.
Ebird.com lets you either search where a certain bird has been sighted in your area, or you can see a list of birds spotted at a particular place. For example, their maps of Providence, Washington and Newport Counties show several areas where Eastern Bluebirds have been spotted. A look at Kent and Bristol Counties indicate that they have insufficient data for those areas. Definitely a great add for my favorite birding websites.
Article compiled by: Renee C. Brannigan
SOURCES:
http://www.allaboutbirds.org/guide/Eastern_Bluebird/lifehistory
http://en.wikipedia.org/wiki/Eastern_Bluebird
https://ebird.org/
http://www.invasivespeciesinfo.gov/animals/eurostarling.shtml
Posts
No comments:
Post a Comment