Food of the Crow, Corvus brachyrhynchos Brehm, in South-central Kansas — John Shaqi
Food of the Crow, Corvus brachyrhynchos Brehm, in South-central KansasPlatt, Dwight R.
Science
Food of the Crow, Corvus brachyrhynchos Brehm, in South-central Kansas
Platt, Dwight R.
Crows
The technique of pellet analysis is more easily applied to a study of
the yearly diet than is the technique of stomach analysis. The crow is
euryphagous and, as shown by this study, the diets of crows a few miles
apart may differ. Therefore a study made on a limited area within one
biotic community, on a year round basis, and correlated with changes in
the habitat should be of greatest value. For such a study, collection of
stomachs is not practical unless individuals are abundant so that many
can be sacrificed, but collection of pellets is practical and
profitable.
One limitation of data based on material from pellets is the
impossibility of closely correlating the volume of indigestible residues
with the proportion of food items actually eaten. Such correlation is
prevented not only by the different percentages of indigestible residues
in different food items but also by irregularities in regurgitation and
in the efficiency of the crow's digestive system. Barrows and Schwarz
(1895:24-25) cite several instances of such irregularities in captive
crows. In certain pellets that I studied, part of the wheat or other
grain was undigested or partly digested, whereas in other pellets the
only residue was finely divided chaff. Certain foods that lack hard
parts may leave no recognizable residues in pellets. A captive crow that
I raised did not form pellets when fed soft food. Nevertheless, data
from analysis of pellets when supplemented by field observations, should
serve as a sound basis for valid conclusions concerning the relative
proportions of various foods eaten. The following field observations of
habitat factors aid in interpreting the information obtained from pellet
analysis.
Field Observations and Correlations
RESIDENT CROWS IN EASTERN HARVEY COUNTY.--Although no field observations
were made on feeding behavior in April, the large percentage of oat
hulls found in the pellets suggests that newly sown fields of oats must
have been one of the major feeding grounds in that month. Oats were
planted between February 15 and March 20.
The pellets collected in June were all from the roost of one family
group of crows. This group spent much time in a cherry orchard and in
the shelterbelt near it. Residues of cherry and wheat constituted the
only plant foods found in the pellets. In both frequency and percentage,
scarabaeid beetles constituted the other important food source. The
wheat harvest started on June 17.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account