2012-09-01 / Columnists

Nature Notes

Two Blue Birds: A Closer Look at the Blue Jay and Great Blue Heron
By Patricia Martin

This week’s column is about two blue birds, but neither of them are bluebirds. One is the great blue heron and the other is the blue jay. In the last couple of weeks I’ve become particularly aware of some of their eating habits.

It’s always fun to see the majestic great blue heron, as it stands motionless in the water, waiting for prey to swim by. Their length is about 46 to 52 inches with a wingspan of 77 to 82 inches. They’re blue gray in color, with a long, curving neck. Their long legs are dark, and they have a straight, yellow bill. During the breeding season, the colors are richer and plumes streak from crown and throat. In flight, their neck folds back over the shoulders in sort of an S-curve, which helps differentiate them from the sandhill crane, which flies with its neck extended. Great blue herons are sometimes called “crane” or “blue crane,” but they’re the largest, most widespread, and best-known heron in North America.

Great Blue Heron (Photograph courtesy of Betty Murcko) Great Blue Heron (Photograph courtesy of Betty Murcko) During the summer they’re common breeders and migrants, but it’s rare that they spend the winter in Michigan, and then only occasionally in the southern part of the Lower Peninsula. They nest communally in treetop nests called rookeries, though once in a while the nest may be placed on the ground. The nest itself is a stick and twig platform, which is added onto year after year and may be up to four feet in diameter.

These birds forage along the edges of rivers, lakes, marshes, fields, and wet meadows. On Mackinac they’re commonly seen all over. I’ve spied them on roofs of houses and barns and flying overhead, but most often in or near the shallows of the lake or various ponds. Recently, I’ve seen one several times down by Mission Point in the small ponds or by the inlet.

Great blue herons can often be seen wading in the water and then standing patiently waiting for a fish to swim by. Small fish are probably their most common food, but they will also eat amphibians, small mammals, aquatic invertebrates, reptiles, and occasionally they’re scavengers for scraps of human food. A few weeks ago Betty Murcko sent me a wonderful photograph of the great blue heron having used its lightning-fast, dagger-like bill to grab a frog from the edge of the cove at Mission Point. This is the kind of food that we usually think of these herons eating, however, a few years ago, a friend called to tell me of another dinner a great blue heron had eaten. She was in her home by the water, and there was a heron, which commonly hung around. She heard a cry and then a shout from her daughter and looked out the window. The great blue heron had carried off a young Eastern cottontail rabbit. We could use a few more bunnyeating herons around here with the number of rabbits eating our gardens this year.

The second blue bird I wanted to mention is the blue jay. This very common, year-around resident of our area is easily identified by its blue crest and black necklace, blue upper parts, white underparts, white bar and flecking on the wings, and dark bars and white corners on the blue tail. The strong beak is black. The other identifiable characteristic is its noisy, screaming “jay-jay-jay,” or as some call it, “thief-thief- thief.” It’s interesting to note that, although we see these birds all year around, the jays that spend the winter here are not necessarily the ones who spend the summer. Our summer jays usually head a bit further south for the winter, and the winter ones come here from the Upper Peninsula or Canada.

Blue jays are one of the most common birds in the eastern half of North America. They’re a member of the corvid family, and have some of the most admirable and aggressive traits of that family, which includes magpies, crows, and ravens. They can mimic other birds, especially hawks. Jays were once considered a forest dweller, but have adapted to parks, cities, and gardens and also fragments of forests. They’re beautiful and resourceful, and may be a bit of a bully at a feeder. They seem unafraid, and will, in a mob or on their own, drive away smaller birds, squirrels, and even a cat if threatened. I think I mentioned a few weeks ago a blue jay and a crow chasing each other back and forth along a fence, before doing the same in an aerial pursuit. They may even harass a bird as formidable as a great horned owl.

Recently, the eating habits of the jays have caught my attention. If you read the bird books, it says that they forage on the ground and among vegetation for nuts, berries, eggs, nestlings, and birdseed. They also eat insects and carrion. The books don’t mention that they love to eat apples. In the last few weeks, with my apples ripening, I’ve noticed an abundance of jays in my yard. Some guests of mine said they spent quite a bit of time having fun watching the jays from their bedroom, picking at an apple and then going to another and pecking a hole in that one, too. They don’t eat the whole apple, but merely go from one to another pecking holes. I just wish they would take one and eat the whole thing, instead of ruining so many.

This is not the only eating habit that is not so nice. Blue jays, in the spring, eat the eggs and the young of other bird species. Audubon wrote this about the jay: “Everywhere it manifests the same mischievous disposition. It imitates the cry of the sparrow hawk so perfectly that the little birds in the neighborhood hurry into thick coverts, to avoid what they believe to be the attack of that marauder. It robs every nest it can find, sucks the eggs like the crow, or tears to pieces and devours the young birds.”

Audubon’s illustrations of the blue jays even show them eating the stolen eggs. The reduction and fragmentation of the eastern forests have given birds like the jays more access to nests of woodland birds, and have helped in the decline of birds like warblers and vireos.

One interesting note on bluehued birds like the jays. The blue color that is seen is not from pigmentation in the feathers, but is instead the result of light passing through the internal structure of the feathers, which sets up interference, which gives the appearance of blue. If the “blue” feather is crushed, it destroys the structure and the blue color disappears.

Trish Martin is a year-around resident of Mackinac Island, has earned a master’s degree in botany from Central Michigan University, and owns Bogan Lane Inn.

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