Feeding behaviors of Bark Probing and Bark Gleaning Birds By: Zac Wert Steph Findley Jonathan Confer
Introduction • Bark-probing birds and bark-gleaning birds compete against each other for the same prey. • All woodpeckers are insectivores • Each has its own way of foraging which keeps them from out sourcing each other.
Hypothesis • The foraging behaviors and habitat selection will differ between species of bark probing and bark gleaning birds
Foraging Characteristics • Bark probing is looking and probing beneath the bark. • Bark prying is when the bird is prying up pieces of bark to reach insects underneath.
Foraging Characteristics • Bark gleaning is when the bird eats from the surface of the tree only and does not forage under the bark. • Bark pecking is when the bird chips away the bark to reach the xylem of the tree directly beneath.
Locations where Observations were Taken • Conrad Weiser State Forest located on Rt. 42 approx. 12 miles south of Bloomsburg • Mixed hardwood forest including: black cherry (Prunus serotina), sugar maple (Acer saccharum), red maple (Acer rubrum), white oak (Quercus alba), American elm (Ulmus americana) and shagbark hickory(Carya ovata). There is also a large stand of Eastern hemlocks (Tsuga canadensis).
Locations where Observations were Taken • Lititz, Pennsylvania (Zac’s backyard) • This area had trees that included: sugar maple (Acer saccharum), black locust (Robinia pseudoacacia), black walnut (Juglans nigra), red oak ( Quercus rubra). • Feeding was primarily done on the sugar maple, black locust and black walnut.
Locations where Observations were Taken White Hall, Pennsylvania (Jon’s Backyard) • Near Montour Preserve • Jon’s backyard has sugar maple (Acer saccharum), black walnut (Juglans nigra), red maple (Acer rubrum), and white pines (Pinus strobus)
Observation Technique- Methods • Birds were observed using binoculars • The birds were observed for a short period of time-creating a snapshot image of the bird. • Notes were taken on that snapshot. • Observations were written down in waterproof notebooks • Feeding height was estimated • Tree height categorized into: lower region = 0ft to 10ft middle region = 10ft to 20ft upper region = 20ft to 30ft
Observation Technique- Methods • Tree size (diameter) categorized into: • Large: Greater than 10 inches in diameter • Medium: 5-10 inches in diameter • Small: Less than 5 inches in diameter • Branches: Not feeding on the trunk of the tree • Side of the tree the bird fed on: • Shaded • Sunny • All
Observed Hairy Woodpecker Feeding Behaviors • Observed foraging for food at all three height elevations • The hairy woodpeckers worked from the bottom of the tree and worked their way up the side of the tree at a quick pace. • This would go on until they found a place that seemed ideal and they would stay there for a few minutes foraging under the bark. • Observed foraging on specific trees not random ones • The hairy woodpeckers were seen foraging on shagbark hickories and white oak.
Observed Hairy Woodpecker Feeding Behaviors • Observed foraging on shaded side of tree • Observed that pecking was not just random fast motion, birds angled heads to get underneath the bark and chip away pieces. • After the bird left the tree, we observed the insect damage. It was determined that there was extensive beetle damage, and larva were also found under the bark of one tree the hairy fed on.
Observed Downy Woodpecker Feeding Behaviors • Observed foraging in the lower two thirds of height elevations of trees 0ft to 30ft • Similar feeding behaviors as a hairy woodpecker (not quite as aggressive when pecking).
Observed Tufted Titmouse Feeding Behaviors • Observed in the upper and middle regions of tree heights 20ft to 30ft 10ft to 20ft • The titmouse was also seen perched in the crotch of the tree on a branch, and flying at the trunk to chip away bark. • The titmouse would then fly back to the perch and watch the area that was just pecked. They would then forage the area.
Observed Brown Creeper Feeding Behaviors • Observed in lower and middle regions of tree heights 0ft to 20ft • The creeper started at 2ft and worked its way up the tree to about 20 ft. • It would then move to a different tree. • Visual feeding, would only feed on insects it could see and would never pick or dig at the tree.
Observed Northern Flicker Feeding Behaviors • Observed in upper and middle regions of the feeding area 10 ft - 30 ft • The flicker was observed starting at the base of a branch and working its way up in a spiral (foraging on all sides of the tree). • In one observation it stopped at the holes already made on the tree to forage inside.
Observed White-breasted Nuthatch Feeding Behaviors • Observed feeding in all regions of the tree. • The nuthatch was observed feeding head down and worked its way down the tree in a spiral. • The nuthatch foraged by gleaning.
Discussion on Observations • It was observed that all regions of the tree were utilized when the birds were foraging alone. • Pecking and gleaning were the main foraging types that was observed in all species of bark-probing birds. • The food that the birds were foraging for was also universal. • Beetles, ants and wood-boring insects • An overwhelming majority of the birds were observed foraging on the shaded side of the tree.
Discussion of Observations-What sets them apart? Tufted titmouse, Hairy, N. Flicker, Nuthatch 20ft to 30ft Hairy, Nuthatch, Tufted titmouse, Downy, N. Flicker 10ft to 20ft Hairy, Brown creeper, Nuthatch, Downy 0ft to 10ft
What sets them apart? • When there were more than one species of bark-probing birds foraging on the same tree, they each foraged in different areas.
Observational example: • Ex. It was observed that a hairy woodpecker and a white-breasted nuthatch were foraging on the same tree. • The nuthatch was seen foraging on the lower region of the tree while the hairy foraged on the middle region of the tree. • Each bird forages by gleaning but the hairy has also been seen pecking, probing and prying.
Conclusion • It was observed that the foraging behaviors and habitat selection were different among the observed species.
Thank You For Listening • Any Questions?????????