Owl
Pellet
Dissection
What is an Owl Pellet?
• An owl pellet is the feces that is
regurgitate. Owl's cannot digest fur,
feathers and bones, that is the main
reason of regurgitation. An owl will still
produce urea.
• Pellets range in size, it all depends on the
size of the owl and the amount it has
eaten.
Background
• The owl pellets that will be distributed to the students come
from barn owls. Barn owls are medium sized owls with large
heads and long legs. The size of the cranium is due to the
enhanced sight sensitivity for seeing in the dark as well as the
vast aural capacity enabling the owls to hear the faintest sound
made by their prey.
• The barn owls are found all across the globe. They are mostly
found in fields and pastures because of the increased rodent
population, their favorite prey. All owls have an interesting way
of dealing with their food. After digesting the nutritious parts of
the small animals they eat, they regurgitate all of the
undigested parts in a small pellet.
• The pellet is composed of bones, fur and teeth. Because barn
owls don't tear their prey to pieces, there is always a complete
skeleton of at least on rodent in every pellet. Every bone from
the skull to the last tip of the tailbone can be found. A good
observer with a little patience will be able to piece together the
incredible skeletal masterpiece.
Objectives
• This activity is designed to give students a
"hands-on" interaction with the process of
different animal digestions, the skeletal
system, predator and prey anatomy and
how its anatomy is tailored for its survival.
Bones to Look for.
Create a Food web Using the
following data
Eats
Taken by
Grass
Converts Radiant energy
Grasshopper, vole, deer
mouse, house mouse,
Gopher, DDD
Seeds
Converts Radiant energy
beetle, vole, deer mouse,
Gopher, songbirds, DDD
grasshopper Grass, Seeds
Shrew, songbirds, DDD
Beetle
Seeds
Shrew, songbirds, DDD
Garter Snake
Deer mouse, vole, beetle
Owl, DDD
gopher
Grass, seeds
Barn owl, DDD
shrew
Beetle, grasshopper, vole,
Barn owl, DDD
deer mouse, house mouse,
songbirds
seeds, grasshopper, Beetle
Barn owl, DDD
Deer mouse
Grass, seeds
Barn owl, DDD
vole
Grass, seeds
Shrew, Barn owl, DDD
Barn owl
?
DDD
Food Chain
Food web
Food web
• An ecological pyramid is constructed
based on one of three types of data:
– number of organisms
– the amount of biomass
– amount of energy.
• Each feeding (trophic) level passes
10% of its stored energy to the next
level.
– Therefore, if the producers had 10,000
units (calories) of available energy,
– the herbivores would receive 1000 units,
– the primary carnivores 100 units
– the secondary carnivores 10 units.
Sites Used for Pictures and
References
• http://www.cnr.vt.edu/forsite/owlpellet/josh/
josh2.htm
• http://www.eelsinc.org/id43.html
• http://www.scienceman.com/pgs/archive21
_owlpellet.html
• http://cas.bellarmine.edu/tietjen/Laboratori
es/Owls2/owl_lab.htm