Eggs, larvae and adults of the four subspecies of Hy la regilla
occurring in Oregon as given by Jameson, Mackey and Richmond
(1966) were collected and subjected to salt stress in a series of
graded seawaters.
It was found that in all cases adults were more tolerant than
larvae and...
In recent years, studies dealing with temperature regulation,
temperature sensitivity, and physiological responses to temperature
in lizards and other reptiles have increased tremendously. It is
notable that snakes have been largely ignored in such studies. This
no doubt is due to their less direct relationship to ancestral endotherms.
However, problems...
The object of this research is to ascertain the habitat occupied by each of the three species of voles of the genus Microtus found living in Northern Benton County, Oregon.
The role of orange coloration in the breeding behavior of
Gambelia wislizenii was examined in the Alvord Basin of southeast
Oregon. Behavioral observations of free ranging lizards supplemented
field experiments where I manipulated the sex and color of lizards
encountered by resident female G. wislizenii before and after they
acquired...
The embryonic and larval stages of the long-toed salamander,
Ambystoma macrodactylum are described from fertilization through
the development of five toes on the posterior limbs. New stage numbers
are employed in the description of the hind limb.
The eggs used in the study were obtained by the injection of
pituitary...
In the summers of 1973, 1974 and 1975, I investigated population
age structure and density, and behaviors relating to habitat
selection, predator avoidance and intraspecific interaction in a population
of northwestern salamanders in a lake in the Oregon Cascade
Mountains. The study was carried out by skin- and scuba-diving at...
Dicamptodon is the single, extant genus of the
ambystomatid subfamily Dicamptodontinae. Two species, D.
ensatus (Eschscholtz) and D. copei Nussbaum are recognized.
D. ensatus is found in the forested, mountain regions of
northwestern California and western Oregon, in the Willapa
Hills and Cascade Mountains of Washington, in extreme
southwestern British...
During summer and fall of 1981 to 1983, mark-recapture was
conducted in riparian and upland habitats within old-growth and
mature forests in the Cascade Range of Oregon. Number of
individuals and species richness were greater in riparian than
upland habitat. For most species, the mean adult weights and
the percentages...
An investigation was made of the factors which cause differences in growth rates and transformation size of bullfrog tadpoles under natural conditions. Tadpoles and algal samples were collected from two.adjacent farm ponds of similar size during the eighteen months of the study. It was found that the tadpoles in one...
Description of anuran larvae with the use of staging tables is
a common practice in the study of frog life-histories, but there has
been no previous description or table of Ascaphus larvae. In comparing
Ascaphus larvae to a simplified staging table for anurans it
was found that these larvae vary...
In the field of herpetology, most studies of homing have been
carried out with anurans and, to a lesser degree, reptiles. Studies
of orientation and navigation in urodeles have been limited to a few
brief notes and the extensive investigation of Taricha rivularis by
Twitty (1959 and 1964).
The rough-skinned...
Phenetic relationships in insular populations of Lacerta sicula
and L. melisellensis correspond to geologic ages of the islands in two
regions of the Adriatic Sea. Populations of L. melisellensis on older
islands are more similar to populations of L. sicula than are L. melisellensis
from younger islands, and examination of...
There are essentially no publications dealing with the skin toxin
of Taricha granulosa. This study has undertaken investigations with
this toxin in an attempt to determine its potency and its effect on the
newt's potential predators.
Test solutions were made by macerating a known volume of newt
skin in a...
Over 56,000 hours of locomotor activity of Taricha granulosa
were recorded using two types of low cylindrical plastic monitoring
chambers. This species shows distinct rhythms of activity under
normal day-night cycles, shortened day-night cycles, constant
darkness (DD) and constant light (LL). The rough-skinned newt is
day active and crepuscular. I...
Life history attributes and apparent distributional
patterns suggest that Plethodon dunni exists as small, semi-isolated
populations throughout its range. Isozyme and morphological
variation in this species was examined to determine
any possible geographic trends.
Starch gel electrophoresis was utilized to examine
genetic variation at 24 isozyme loci in 287 individuals...
The western Plethodon include vandykei vandykei, v. idahoensis,
larselli, dunni,vehiculum, stormi, elongatus, and an undescribed
form referred to as the "unstriped" Plethodon. These
salamanders have been placed into three species groups: the
Vandykei group, the Vehiculum group, and the Elongatus group.
Range maps are provided and geographic variation is discussed...
Experimental crosses between Rana pretiosa pretiosa Baird
and Girard and Rana cascadae Slater, resulted in viable hybrids.
Reciprocal differences at the time of fertilization are indicated. A
high level of success in producing viable hybrids can be obtained if
Rana pretiosa pretiosa is the female of the parent species, The...
Developmental series of Rana pretiosa (110 specimens), R.
cascadae (100 specimens) and R. aurora (115 specimens) were bone
stained and cleared in glycerin. The growth and developmental patterns
of the skull and selected bones were followed from the first
appearance of bone through adult stages. The sequential appearance
of the...
The breeding habits and embryonic thermal requirements of the
Cascade frog of Oregon, Rana cascadae Slater, are described. The
limits of temperature tolerance of the pre-feeding stages are from
6° to 27°C for embryos held at constant temperatures. However, for
pre-feeding embryos exposed at different developmental stages for
short durations...
Laboratory experiments and simulated field conditions were
utilized to gain a better understanding of the ecology of the clouded
salamander.
Animals collected in western Oregon were utilized for studies
in habitat selection, where it was shown that there was a significant
pattern of selection of litter types (rock, bark, and...
The investigation was conducted from January 1965 to March
1966. An intensive effort was made to obtain large numbers of animals,
as it is believed that unavailability of specimens has been the
limiting factor in the amount of research concerning this species.
Two hundred and sixty-nine animals were collected. They...
The purpose of this study was to record on tape and to
analyze the sonagrams of the complete repertoire of the vocalizations of the Rufous-sided Towhee, Pipilo erythrophthalmus
oregonus. Meanings were assigned to a number of the calls.
Sounds of nestlings, juveniles, and vocalizations connected with
parental care were not...
During the spring of 1963 and 1964 an investigation of a small
mammal community was made in McDonald Forest, near Corvallis, Oregon.
The revised North American Census of Small Mammals procedure was
used, and from this census the species composition of the community
was determined. The relationships of several genera...
The ecology of a population of snowshoe hares, Lepus
americanus washingtonii, was studied in western Oregon from 1960
to 1962. Objectives were to obtain information to control hares,
which frequently cause damage to coniferous reproduction in the
region, and to compare the life history of this little-studied subspecies
with others....
With a growing emphasis on details of behavior comes an increasing
need for knowledge of natural behavior patterns. Studies
on the life history of Peromyscus maniculatus have long been available
in the literature. More recently, investigators have turned to
analyzing the behavior of some of the subspecies of P.m. in...
Analyses of sympatric and allopatric populations of Sceloporus
occidentalis and S. graciosus from central Oregon indicate a high degree
of similarity in diet. Relative abundance, the equivalent number of
equally common taxa (E), and the probability of similarity (SIMI) were
used in the analyses. Shifts in diet between populations of...
The karyotypes of five species of ranid frogs were determined
from metaphase plates of bone marrow cells. The colchicine, hypotonic-
citrate, blaze-dry technique was used to obtain the plates.
Morphometric datawere obtained from the karyotypes and compared
with other species of the genus Rana.
Like most other members of the...
This report summarizes the results of a field study of a population
of the Pacific mountain beaver, Aplodontia rufa pacifica, from
August 1965 through August 1967. The study site consisted of a 13. 5-
acre grid on a logged over area in the Coast Range Mountains of
Benton County, Oregon....