Saturday, November 26, 2016

Woodpeckers, especially the red bellied woodpecker.

Male red bellied woodpecker. Note the red on its head extends from eyebrow
to the nape of the neck in the male. Also note its toes: two toes forward, two
toes back to enable better grasp when it is vertical on a tree trunk.

This is the female near a nest hole. Note the red on its head is interrupted and forms only a small patch near its
beak and then a long patch from the back of the head to the nape of the neck.

     Woodpeckers are fascinating birds. I originally wanted to write about the red bellied woodpecker because I have now had a nesting pair living and breeding on our property. I saw and heard the male for the first time on January 6, 2016. And the pair has remained the entire year. These birds are monogamous and defend a territory throughout the year.  I still hear it around some of our tall cottonwoods, especially those that have some dead branches. I heard the young begging for food right outside our front door most of the summer. These birds can sometimes hammer on your downspout or metal gutter because they have learned that these structures serve as excellent amplifiers for their communicative tapping. Some of their tapping is to excavate a home in dead wood, some is while foraging for grubs and insects beneath the bark of trees, and some is to warn others away from their territory or to attract a mate during the courting season.When such tapping is carried out on your fascia, soffit, and gable boards it is not as noisy but may be a sign of insect infestation in your wooden house. We have had some tapping on the front of our house on the gable and at least once have had to fill some shallow holes with wood filler. In spite of these risks, I am pleased to have the red bellied woodpecker as a guest in our yard. And I have learned that a pair of red bellied woodpeckers can remove as much as 85% of the emerald ash borer larvae in a single tree in a single season. We have 4 still living green ash trees and paid for injections for all 4 this year though there was no sign of definite infection yet. Maybe my red bellied woodpeckers will also help preserve these trees. The link that follows shows a red bellied woodpecker in action on trees and on the gable of a house much like we have experienced.

Red headed woodpecker
Here you can see a small
patch of red in the lower
belly of this female.

    Since you have examined the photos above and perhaps even seen a living and drilling red bellied woodpecker in the wild, you may wonder about its name. Where is the red on its belly? It certainly has a red head or at least a red stripe on its head. But the name, red headed woodpecker has already been used. And it is clear that that common name is very apt for the woodpecker pictured on the left. They are striking birds! We had a pair raising their young in our back yard several years ago, but they have apparently not found a suitable nesting tree lately. It is true that in suburbia, especially in our area, people tend to keep their dead trees and branches trimmed and removed. Thinking they are ugly, folks often remove snags as soon as they are obvious. And of course, with various tree diseases, the authorities and arborist do recommend getting rid of the dead wood. But this practice certainly hurts species like all woodpeckers.

Male pileated woodpecker
     Some of you may be familiar with the large crested pileated woodpecker pictured here. This species is rather secretive and prefers mature hardwood forests in the north in Wisconsin.  But the species ranges throughout the Eastern US, Canada, the northern boreal forests of Canada and in forests along the west coast of the US. I have only see this bird once. We were traveling to the south and at the edge of a woodlot near a motel we stayed at in Tennessee.  From a distance I saw several pileateds fluttering along the trunk of a tall tree. This woodpecker is often given the honor of modeling for the famous cartoon character,
Woody Woodpecker, whose laughing voice we all recall. Certainly the character resembles the
Acorn woodpecker
                pileated woodpecker with his red crest, but the creator of the cartoon maintains that he modeled the anthropomorphic woodpecker after the acorn woodpecker that resides in many park areas of Southern California. Walter Lantz created Woody  in the 1940s along with storyboard artist, Ben "Bugs" Hardaway, creator of both Bugs Bunny and Daffy Duck for Warner Brothers. I chased down the acorn woodpecker to add it to my life list in a regional park in Orange County while visiting my son at University of California, Irvine. Certainly the acorn's antics seemed similar to Woody Woodpecker's antics.

     Anyone who pays any attention to the birds at their feeder at all, especially if suet is being fed, will know of the downy woodpecker and the hairy woodpecker. The problem always is telling them apart when only one is present at the feeder. There are a couple of tricks that can help. Certainly the hairy woodpecker is slightly larger but that may be hard to judge when just one bird is seen. It might help to know that the downy is the size of a house sparrow while the hairy is the size of a robin. Also you can identify them by their bill. The downy has a very dainty bill which is about a third of the length of its head, while the hairy has a big stout bill which is almost as long as the length of the hairy's head. A more subtle field marking is the side tail feathers. The hairy has all white side tail feathers whereas the downy has 2 or 3 small black spots interrupting the white of the side tail feathers. Another clue is that the downy woodpecker is much more common, particularly in suburbia, so they will be much more likely to be seen at the feeders. The hairy woodpecker prefers woody areas and tall trees so will be less likely to be seen in the suburbs. Compare the two photos below.

Downy woodpecker

Hairy woodpecker

Yellow bellied sapsucker
        There are a few other woodpeckers that are on my life list. Of course yellow bellied sapsuckers are fairy common around our location especially during migration. They spend winters in the southeastern US, in the West Indies and in Central America. These woodpeckers also nest in cavities that they excavate. But they also feed on sap and the insects they draw by drilling small holes in a line up and down a tree. If they happen to girdle the tree, the holes can kill the tree. There is also a fungous infection of aspens which causes the heart wood of the tree to soften and attract sapsuckers to nest there. A colony of sapsuckers can take residence and badly damage a stand of aspen. In these cases, the fungoused trees are removed to prevent a sapsucker colony from forming. There are three other species of sapsuckers but they are not nearly as common as the yellow bellied in our area.

Red cockaded woodpecker

     My birdwatching is not usually such that I will drive way out of our way to find a specific bird. But on this occasion in 2003 on a trip to Jackson, MI to meet our future daughter in law, we did make a jaunt east a to find the red cockaded woodpecker. This is one of the most studied birds in our country. It has been very threatened due to loss of habitat in the Southeast of our country. It was estimated to be down to a low of 3,000 family units but through restoration projects its estimated that there are now over 6,000 family units. This bird is a cousin of the red bellied woodpecker but its behaviors are quite different. The birds prefer to nest in tall mature pine forests that have been subject to fire so that the understory is quite thin. They also prefer very mature trees, often 80 year old trees, because these elderly ones are often subject to a fungous disease that softens the heartwood and makes it easier for this woodpecker to excavate a nest hole. Even so it often takes a pair a couple years to form their nest hole. They also have the habit of drilling small holes around the hole which fill with pine sap. It is thought that this oozing sap provides a barrier against a local predator snake that tends to seek out the nestlings. Due to these very specific requirements, there are not many stands of burned out open mature fungous infected pine trees in the Southeast of our country. Efforts have been made to get lumber companies and private land owners to leave about 10 pines to mature per acre specifically for this woodpecker. Also controlled fire burns, artificial nest cavities, and transferring family units from private land to National Forest land have all helped to bring this bird back to some degree. The red cockaded woodpecker has an interesting nesting habit. A pair will form and remain pair bonded but often several younger birds, especially males will stay with this pair and help to raise the young. Therefore a family unit often occupies one nest tree and consists of up to 6 or 8 individuals. The name of the bird refers to an occasionally seen few red feathers located on the side of the head of the male just above and behind the eye at the edge of the black cap. One can sort of imagine that color in this photo. Well, our jaunt to Noxubee Wildlife Refuge in eastern central Mississippi did allow me to put this bird on my life list.

There is another interesting family of birds that are related to the woodpeckers but they do not exist in our hemisphere. There are two species of these birds. They are called the wrynecks. When I went to a birding conference in Ailat, Israel in the 1980s, I participated in some bird banding and we were fortunate enough to band a Eurasian wryneck. They winter in The Sahel or sub Saharan Africa and then migrate north as so many birds do in the Eastern Hemisphere to breed in Eurasia. Israel forms a land bridge for a multitude of different species as they migrate out of Africa and into Europe and Asia. Therefore the Spring migrations in Israel are absolutely phenomenal for bird sightings. There is a yearly Spring Migration Festival in Ailat. Because this city is on the Red Sea and has some artificially created date palm fields and other vegetation as well as some fresh water, it serves as an oasis for these birds who are on such a long journey through desert and inhospitable territory.

     Think about the woodpecker behavior of drilling repeatedly on the hard wood of trees both to excavate a hole for breeding as well as to forage for food and to communicate with other woodpeckers and proclaim territory. Think of our human brains and how susceptible we are to concussion with just a single head bump. How do these woodpeckers do it? Well, interestingly, they are built for concussions. First their bill consists of three layers: the outer layer is strong keratin like our fingernails; the inside layer is mineralized collagen fibers and in the cavity between these two layers is a very porous spongy compressible bone. The bird's brain itself is smooth and fits very tightly inside the skull so that it can't move around a lot during the drilling and drumming action. The subdural space is very narrow and there is very little cerebrospinal fluid. Also the skull especially in the front and in the back has a very spongy compressible bone to help absorb the blows. In addition, the drums are very short and quick. It has been found that 99% of the energy created by the drum is converted to what is called strain energy. It is absorbed in elastic tissues and very quickly distributed to the entire body of the bird. That does create heat, however, and it is thought that that is why the woodpeckers only drill for a short time and then rest to let the brain cool off. Fascinating, isn't it? 

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