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Pileated Woodpecker whereabouts in the Morgan Arboretum

Research Question

In order to to investigate where the Pileated Woodpecker (Dryocopus pileatus) is predominantly found within the Morgan Arboretum and whether they have a preference in area or tree they target, we asked ourselves the following question. “Is the Pileated Woodpecker (Dryocopus pileatus) more active (excavate more trees) in certain parts of the Morgan Arboretum, and does this activity correlate with a dominant tree type?”wp1

From our research on the Pileated Woodpecker, we found that they are said to nest in large, dead trees and feed predominantly on insects (Bull 1987). In one study, it was noted that Pileated Woodpeckers predominantly avoided young trees and preferred more mature ones for foraging (Savignac et al. 2000).

From this, the objective of our project was to see if our results concurred with those of the different scientific studies of the past. Seeing as there were no known studies exactly like ours, we also attempted to find results that are region specific to the Morgan Arboretum. Our goal was to determine whether the Pileated Woodpecker is more dominant in one area of the Morgan Arboretum and to see whether it has a preference in a certain family of tree.

Methods

In order to study the Pileated Woodpecker the Arboretum was divided into 12 unique sectors each of which has different dominant tree types. Transect lines were then plotted on the map so that each sector had a total of 480m of transects within it. This was predominantly achieved by using six transects of 80 m, each 40 meters apart from each other. In the field, these transects were then walked along and any trees with Pileated Woodpecker excavation damage within 10 m of the transect were recorded. Multiple measurements were taken including diameter at breast height, the tree’s status (alive, dead or dying), GPS coordinates, tree family as well as any relevant notes about the area. All transects were carefully plotted so that no two transects intersected, or certain areas were surveyed more than others. Data was collected and entered into the mobile application iNaturalist.

Update [21/11/13]: A map showing the distribution of woodpecker work in the Arboretum is now available.

Physical Traitswp2

The Pileated Woodpecker is a recognizable bird with its large size and red crest on it’s head. Its body and wings are mostly black with white stripes down its neck.  The males have a red mustache while females a black one. They have a strong stout bill, a muscular body, and an air encased brain and fortified skull which helps them produce holes for foraging and nests (Benyus 1989).

Behaviour

The Pileated Woodpecker communicates with both instrumental and vocal sounds, along with physical displays. Instrumental can be drumming, drum tapping or rapping their bills. Their vocalizations (known as  “wok”s) can express a variety of of things by varying in speed, pitch and tonality. Dominance of an area, attempts to attract mates, and alarm calls are some examples of these calls. These territorial birds express dominance with sounds and conflict can occur with full-wing threat displays and air grappling. They also communicate with bill waving and crest raising (Kilham 1959).

Natality

The Pileated Woodpecker starts breeding at one year of age and lives monogamously. The clutch size ranges from three to five eggs with one brood each summer. Both sexes excavate a nest that has an entrance that is just big enough to enter and is 25 to 60 cm deep (Hoyt 1957). The incubation period is between 15 to 18 days and both parents alternate with the male having the responsibility at night. Both parents feed the hatchlings but the male still has the task of night brooding. The altricial young can fly after 24 to 28 days, but remain close to the nest, during which the parents teach them to forage, until the fall when the young disband (Hoyt 1957; Bull 1988).

Diet

Like most birds, the Pileated Woodpecker has seasonal eating habits. About 75% of the year is spent eating insects while the other 25% is mostly spent eating fruits and wild nuts. wp3During the fall, the Pileated Woodpecker tends to eat more fruits and wild nuts. After fall has passed, they spend the rest of the year mostly feeding on insects like the carpenter ant (Camponotus spp.) which is commonly found in beech and pine trees.  The woodpecker excavates these trees to extract the deep-dwelling ants inside as well as beetle larvae, which are found closer to the surface. To find food they listen for the movement of the insects with their excellent sense of hearing. The excavations of the Pileated Woodpecker are very distinct. Unlike smaller woodpeckers, the Pileated Woodpecker makes rectangular excavations that can be 30 cm or more in length. Come summertime the woodpecker has a more varied diet including fruits, berries and insects (Hoyt, 1957).

Predators

As for predators, the adult Pileated Woodpecker is preyed upon by large raptors including some hawks and owls (Bull et al. 1992). Eggs and hatchlings risk predation by a variety of mammals including American marten (Martes americana), weasel, and Eastern grey squirrel (Sciurus carolinensis) (Bull et al. 1992; Belasco 2001).

Habitat

wp4These large birds prefer older growth forest for its roosts as they require a lot of space for their mates and young, and the older trees tend to be wider with larger interior diameters. Typically they prefer trees whose diameters at breast height (or DBH) are in excess of 30 cm, whether it be deciduous or coniferous (Lemaitre 2005). They are not random in their selection of trees for roosting however: most trees will have interiors that have decayed naturally, and the birds will simply create the openings and perform a bit of interior decoration, usually with wood chips (Bull 1993). They are often considered an indicator of disease in trees.

Range

The Pileated Woodpecker is a year round resident throughout its impressive range, which spans North America from coast to coast. They can be found as far south as Florida on the east coast and as far north as the Yukon on the west coast. See here. They divert around the central mid-western United States, avoiding the great plains region bounded by the western edges of Oklahoma to Wyoming.

Want to know more? Check out The Pileated Woodpecker, on Cornell University’s All About Birds website.

Works Cited

Belasco, Jon. 2001. Pileated Woodpecker. The Virtual Nature Trail at Penn State New Kensington [Internet]. [2013 October 20]. Available from:  http://www.psu.edu/dept/nkbiology/naturetrail/speciespages/pileatedwoodpecker.htm

Benyus, J. 1989. The Field Guide to Wildlife Habitats of the Eastern United States. New York: Simon & Schuster.

Bull EL, Holthausen RS. 1993. Habitat Use and Management of Pileated Woodpeckers in Northeastern Oregon. Journal of Wildlife Management [Internet]. [Cited 2013 Oct 17] Vol 57(2): 335. Available from: http://www.jstor.org.proxy1.library.mcgill.ca/stable/3809431

Bull EL, Jackson JA. 2011. Pileated Woodpecker (Dryocopus pileatus), The Birds of North America Online [Internet].  Ithica(NY):Cornell Lab of Ornithology; [Cited 2013 Oct 19] . Available from: http://bna.birds.cornell.edu/bna/species/148

Bull EL. 1987. Ecology of the Pileated Woodpecker in Northeastern Oregon. The Journal of Wildlife Management [Internet]. [cited 2013 Oct 21]; 51(2): 472-481. Available from: http://www.jstor.org/stable/3801036

Bull, E. 1988. Breeding and Biology of the Pileated Woodpecker: Management Implications. Portland (OR): U.S Dept. of Agriculture, Forest Service, Pacific Northwest Research Station.

Bull, E.L., Holthausen, R.S., and Henjum, M.G. 2001. Roost trees used by Pileated Woodpeckers in northeastern Oregon. J. Wildl. Manage. [Internet.] [Cited 2013 October 21]

Hoyt, Sally F. April 1957. The Ecology of the Pileated Woodpecker. Ecology Vol. 38, No. 2: 246-256. [Internet]. [Cited 2013 October 20]

Kilham, L. 1959. Behavior and Methods of Communication of Pileated Woodpeckers. The Condor. 61(6): 377-387. DOI:10.2307/1365307

Lemaitre J, Villard MA. 2005. Foraging Patterns of Pileated Woodpeckers in a Managed Acadian Forest: a Resource Selection Function. Canadian Journal of Forest Research [Internet]. [Cited 2013 Oct 19] 35(10): 2387-2393. Available from: http://search.ebscohost.com.proxy1.library.mcgill.ca/login.aspx?direct=true&db=a9h&AN=19103647

Savignac C, Desrochers A, Huot J. 2000. Habitat Use by Pileated Woodpeckers at Two Spatial Scales in Eastern Canada. Canadian Journal of Zoology [Internet]. [cited 2013 Oct 21]; 78(2): 219-225. Available from: http://dendroica.ca/pdf/piwo ms.pdf

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About Crystal Ernst

Hakai Institute postdoctoral scholar at Simon Fraser University (B.C.)

8 comments on “Pileated Woodpecker whereabouts in the Morgan Arboretum

  1. Great work team – I look forward to hearing the results of your research! Two questions: (1) How did you differentiate from a dead or dying tree? Is one dead branch a dying tree or did there have to be a threshold of standing dead wood for it to reach the ‘dying’ status. (2) Since this is an Arboretum that is planted and managed – do you know the age of different plantations or managements? There might be some areas (I’m thinking of the Sugar Maple bush) that was planted all at once and thus all the trees mature and develop dead branches or snags around the same time. Also there are some areas of the forest that are ‘cleaned’ and have dead wood removed. This is harmful for woodpeckers and lots of other forest beasties. Glad to see you representing the importance of dead wood = a very alive forest!

    • Thanks Barbara! We had a really tricky time with the tree status. We looked at the amount of decay, presence of leaves, bark characteristics (whether it would slaugh off, if it was soft) and the extent of any other damage (as the insects would do) and tried to make a decision as a group.
      We don’t know the ages of the various plantations, no, but maybe we could contact someone at the arbo and find that out… also we’d love to know the approximate relative amounts of trees there to compare with our damage by tree type as well.
      Snags were something I never knew about before the project, and I found them very interesting, as well as the management issue of whether to leave them standing or clear them out.
      We really appreciate your help along the way and always love to hear from you.
      -Team PIWO

  2. They’re really quite amazing. They sound like a human is trying to chop down a tree, and you can always tell which trees they’ve been at, because there’s a HUGE pile of wood chips at the base of the trunk. They’re also vicious art critics. We stayed a lodge in the Paradise Valley once, just outside of Mount Rainier National Park, and the owners told us that they had spent a couple of hundred dollars on some chainsaw log art for the property that the Pileated Woodpeckers didn’t quite like it. One night they made short work of them by dispensing some rather dramatic artistic criticism courtesy of their beaks.

    • That wood is perfect for other critters nests and constructions in the woods, as well as a nice nutrient source to the soil. The PIWO (birder shorthand for Pileated Woodpecker) really is a team player. Plus if they come a knocking, it’s probably because the tree is in a bad way anyway, this woodpecker just wants to help hurry on its way.
      Unfortunately for the log art, PIWO hate missing an opportunity for a snack. They probably figured another, larger bird had found some food there!
      Thank you for sharing your story with us James, all the best.

  3. […] of hard knocks. Excavations by pileated woodpeckers. Super research blogging by students from McGill […]

  4. Very interesting info. It gives me the taste to go into the woods near my house to see if I can recognize any of their trademarks on some of the dead and dying trees.

  5. Good info on how to find them via wood chips on ground. I have these in my woods out back. At first I thought it was some kind of turkey making those sounds and all I could see was a large dark colored bird. I want to plant fruits or nut trees they like, but I am not sure what kind. They are not coming to eat the fruit I put out. any ideas?

    • Hi! Woodpeckers are actually insectivores – they feed on insects hiding under the tree bark or in the woods, which is why they drill holes in them – to extract their food! That said, in winter many woodpeckers will happily feed from a ball of suet (fat) – you might consider trying this later in the year!

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