Attracting bluebirds

Trees and plants for bluebirds, advice about bluebird house placement

Eastern bluebird - United States Geological Survey photo

If you want to attract bluebirds year after year, consider planting some of the fruit-bearing trees and other plants that they like. Fruits are an important part of their diet, though they eat insects, snails, and spiders as well. Here are some of their favorites:

Fruit-bearing trees for bluebirds: Dogwood Redcedar Wild cherry Serviceberry Sumac Bayberry Holly Hackberry

Other fruit-bearing plants for bluebirds: Pokeweed Virginia creeper Poison ivy Mistletoe Wild grape Blackberry Elderberry Bittersweet Blueberry

Where to place a bluebird nestbox:

In unspoiled nature, bluebirds nest in holes or cavities in dead trees. Obviously, dead trees don't have much foliage around the nest area -- just vines, at most. Bluebirds prefer their man-made houses to be placed in similarly open areas. They don't like a birdhouse that is hidden within a bushy clump of leaves and branches.

A steel fencepost in the longest size that you can find (7 ft. is generally available) makes a good, inexpensive pole for mounting a bluebird house. The steel post is difficult for animal predators to climb and if the box is mounted at the top of it, it is at an adequate height to satisfy bluebirds.

Bluebirds (and many other birds) prefer to nest near a source of water. If you don't have a stream or pond, provide a birdbath and be sure to tend to it.

Bluebirds are territorial. They are require at least a 100-yard circle of "private property". If you live in a neighborhood of closely-spaced houses and your next-door neighbor has a bluebird nest in his birdhouse you probably won't get a nesting pair in your yard. However, you'll still be able to enjoy the birds as they come to your yard to feed on the fruit you've provided for them!

Related post: Eastern redcedar: A tree that birds love

Spring in the Woods

March in Christian County, KY

Two examples of shaggy bark

Young shagbark hickories and an old silver maple

These two young shagbark hickories are growing in a road ditch. To be completely honest, I call all shaggy-barked hickories "shagbarks", but some of them could be shellbarks. I don't have a clue how to tell the difference between shagbark and shellbark hickories from the bark. There are some minor differences in their leaves and nuts -- enough to make them two separate members of the walnut family.

Here is another shaggy-barked tree -- an aged silver maple. Old silver maples develop long scales of bark that are loose at the ends. This sort of bark on any species of tree is called "exfoliating."

It would be difficult to confuse a shaggy-barked silver maple with a shaggy-barked hickory, though, even in winter when no leaves are present. Silver maple trees have a broad, spreading crown with the central trunk breaking into massive branches. The crown's width may even be more than the tree's height! Shagbark/shellbark hickories generally have a much narrower crown, about half as wide as they are tall, and their strong central trunk persists high into the tree.

Hollow Sycamore Trees

Bonnecamp's cottonwood

Dennis showed me an ad on the back of one of his history magazines. A print of a painting, "We Dined In A Hollow Cottonwood Tree," is being sold. The artist is Robert Griffing, and the firm offering the print is Paramount Press, Inc.

The painting shows three huge canoes pulled up to the bank of a river under an enormous tree. The tree has an opening on its trunk and two people are standing just inside it. They are dwarfed by the tree.

In the text of the ad, it tells a bit about the historic event that the painting portrays. A Jesuit, Father Joseph-Pierre de Bonnecamps was traveling with a group of French soldiers, Canadians, and Indians down the Ohio River. Father Bonnecamps wrote in his journal that they had dined inside a hollow cottonwood tree that was large enough to arrange 29 men inside it. The area that he saw this tree is believed to be near present day Pittsburg.

Dennis and I were puzzled that a cottonwood could possibly grow to such tremendous size since their lifespan is quite short, at most 125 years or so. I decided to do a little research on the subject, and it turns out that Father B. was describing the tree that we call the American sycamore.

Here is the relevant portion of Father Bonnecamp's journal entry for the day. I think the first tree he describes might be a honeylocust, and the second one is the big sycamore:

One of our officers showed me a bean-tree. This is a tree of medium size whose trunk and branches are armed with thorns three or four inches long,and two or three lines thick at the base. The interior of these thorns is filled with pulp. The fruit is a sort of little bean, enclosed in a pod about a foot long,an inch wide, and of a reddish color somewhat mingled with green. There are five or six beans in each pod.

The same day, we dined in a hollow cottonwood tree, in which 29 men could be ranged side by side. This tree is not rare in those regions; it grows on the river-banks and in marshy places. It attains a great height and has many branches. Its bark is seamed and rough like shagreen. The wood is hard, brittle, and apt to decay; I do not believe that I have seen two of these trees that were not hollow...

Source: Bonnecamp's journals, at the Ohio Historical Society's website.

A hollow sycamore that could hold 29 men makes more sense, though that's quite a crowd. Sycamores have enough lifespan (often 350 years and sometimes much longer) to grow very large in favorable circumstances. Early American history records many instances where people lived in hollow sycamore trees until they built a cabin.

Dennis told me of another sycamore he has read about -- it's hollow was so large that two brothers lived comfortably inside it for several years. One brother slept upstairs and one slept downstairs!

Most sycamores over 100 years old are hollow inside. Wood ducks, opossums, and raccoons often nest in the hollow, live tree trunks. As Donald Peattie writes in his 1950 A Natural History of Trees (319) that "...pioneers often stabled a horse, cow, or pig in a hollow Sycamore, and sometimes a whole family took shelter in such an hospitable giant, until the log cabin could be raised."

Source: Sycamores at Wellesley Web of Species

Those pioneers who saw the huge hollow sycamores of the primeval forests wouldn't be impressed by this rather small hollow sycamore that we saw at Cumberland Falls in eastern Kentucky (photo below -- I asked permission of the children's mother to take their picture but I didn't get a release to post their photo online. That's why I have blurred their sweet little faces.)

A search for the exact words, "in a hollow sycamore" returns many interesting accounts of people and other creatures taking shelter in sycamore tree cavities.

Hollow sycamore at Cumberland Falls State Park, KY

Related post: Sycamores: Big Trees with White Branches

Galls on a Young Pin Oak Tree

Abnormal growths caused by insects

This young pin oak tree in Hopkinsville, KY, is sadly afflicted with galls. Galls are spots of abnormal growth caused by an insect. A gall can develop in any part of a plant that an insect can burrow into, and in oak twig galls, the insect is usually a small wasp.

The various university extensions are a great source of information about tree problems like this. Here's a summary of the life-stages of gall wasps from North Carolina State University Extension.

Many gall wasps develop for 2 or 3 years in woody galls on the twigs of oaks. Adults then emerge from the twig galls during the winter. They lay eggs in the buds and die. When these eggs hatch, and new growth resumes on the oak, salivary secretions of the gall wasp grub act as powerful plant growth regulators and force the tree to form the gall. Gall wasp galls typically have an outer wall, a spongy fiber layer and a hard, seedlike structure inside of which the gall wasp grub develops. Although gall wasp grubs have chewing mouthparts, they do not seem to chew plant tissue. Evidently the gall secretes nutrients which the grubs lap up.

Source: Galls on Oaks, by James R. Baker and S. B. Bambara, Extension Entomologists at North Carolina State University.

Branches with galls should be removed and destroyed before the tree's infestation becomes serious. Spraying with insecticides is rarely effective because the wasp spends most of its life as a larva, protected inside the gall. There's a small window of opportunity when it emerges to lay eggs.

A University of Kentucky publication about oak galls states that the weight of the galls can cause stress on infected branches, and the deformation can girdle (thus killing, I assume) a branch.

While researching for this post, I learned some sad news (it was news to me!) about oak trees and galls:

Oaks can have numerous types of galls. Out of the over 800 species of gall making wasps in North America, 731 of them attack oaks. Oak deformities are of various sizes, shapes, and colors on leaves, twigs, flowers, acorns and buds. Galls are so commonly found on oaks that many people think the galls are typical parts of the plants.

Source: "Trees With a Lot of Gall (growths called galls on trees)" by Sandra Mason of the University of Illinois Extension.

I have only seen one other oak around here as badly deformed with galls as the little tree in the photo is. The other tree is a mature pin oak, and it is a sad sight indeed. I'm going to try to watch our oaks here at the house carefully. Hopefully we can "nip the problem in the bud" if it occurs.