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Age determination in juvenal bobwhite quail
Following methods described by Louis Bureau (1911, 1913) in France, tabulations were made (1) of the ages at which captivity-reared bob-white quail ( Colinus virginianus ) dropped their juvenal remiges, and (2) the rates at which post-juvenal replacement primaries grew. These were arranged so as to permit the determination of age in healthy birds from one to five months of age. The degree of individual variation was much greater than that found by Bureau, however, and limits accuracy in age determination after the 10th week. The post-juvenal wing molt began on the birds' 28th day and ended when the quail were 146 to 154 days old. The post-juvenal body molt was found to take place largely between the 70th and 100th days. The juvenal rectrices were renewed from the 62nd to the 122nd days, the new feathers being as long as their longest coverts when the birds were 116 days old. The color of the tarsi varied from pink, at 32 days of age, to straw color at 60 days, and yellow-gray from 83 to 180 days. At six months, the color of the beak was identical with that of adults. Unlike several other game bird species, the flexibility of the lower jaw was not an accurate index to age in bob-whites older than 11 weeks. Rigor mortis and freezing were found to hinder the testing of this criterion.
Wildlife effects of DDT dust used for tick control on a Texas prairie
The effect of DDT dust on wildlife was studied at Camp Bullis, Bexar County, Texas, in the summer of 1947. Studies were made on a 206.6 acre plot that was treated with DDT for experimental control of the Lone Star tick ( Amblyomma americanum ). A dust consisting of one part of DDT to nine parts of pyrophyllite was applied at an average rate of 4.4 pounds of DDT per acre. The limits of DDT concentration that affected wildlife cannot be stated exactly because of a heavy rain that fell near the end of the dusting, and because of irregularity in DDT deposition. Since absolute uniformity of dusting could not be expected in any large scale DDT application, the effects observed in these trials were probably fairly representative. However, continued dry weather would have permitted longer exposure to DDT, possibly with more severe effects than those found in this study. The vegetation of the experimental area was roughly 70 percent ungrazed tall-grass prairie and 30 percent trees and shrubs. Ground and bush feeding birds were severely affected. Cardinals, lark sparrows, field sparrows, Bewick's wrens, Carolina wrens, Kentucky warblers, yellow-breasted chats, blue grosbeaks, and painted buntings were nearly or entirely eliminated from the treated area. Birds affected, but less drastically reduced in numbers, were yellow-billed cuckoo, black and white warbler, yellow-throated vireo, and white-eyed vireo. Birds found dead in the DDT area were 9 cardinals, 2 painted buntings, 2 lark sparrows, 1 yellow-breasted chat, and 1 white-eyed vireo. Bird mortality had begun by the day after dusting and was largely over by the end of the fifth day. Census of deer in DDT and check areas before and after treatment showed no reduction in deer numbers and no diminution in use of the DDT area. No deer or fawns were found dead or affected. Box-trapping of raccoons in DDT and check areas before and after treatment showed no effects that could be attributed to DDT. Limited observations on armadillos, striped skunks, and rabbits gave no indication of pronounced damage to these forms. No mammals of any kind were found dead or affected in or near the DDT area. Four rough green snakes and one Texan spiny lizard were found dead in the DDT area. Mortality was probably high among insectivorous reptiles.
The foods of fur animals of the Patuxent Research Refuge, Maryland
Approximately 300 digestive tracts of fur animals obtained mostly during the winter trapping season and 560 scats from animals live-trapped on the Patuxent Research Refuge near Laurel, Maryland, were analyzed. The resulting data are summarized and a brief description of the area and important habitat types is given. The animals studied include the raccoon, red fox, gray fox, mink, New York weasel, skunk, opossum, and house cat.
Unusual drowning in captive short-tailed shrews
Three captive short-tailed shrews ( Blarina brevicauda ) drowned in attempting underwater escapes from their cages.
Adoption of a nestling house mouse by a female short-tailed shrew
A nursing female short-tailed shrew ( Blarina brevicauda ) adopted a nestling house mouse ( Mus musculus ). The mouse was observed in the nest with the female and her litter of shrews three days after it was introduced into the aluminum box containing the shrews, but it was found dead in the nest four days later.
The survival of coho salmon (Oncorhynchus kisutch) eggs in two Wisconsin tributaries of Lake Michigan
Natural reproduction of coho salmon (Oncorhynchus kisutch) in two Wisconsin tributaries of Lake Michigan (Little Scarboro Creek, Kewaunee Co., and Fischer Creek, Manitowoc Co.), is limited by an unusually high mortality of eggs and preemergent embryos. Of approximately 1800 coho salmon eggs planted in six study redds (spawning beds) within Fischer Creek (November 1972), none survived to hatching. The 1500 eggs planted in five study redds within Little Scarboro Creek produced 21 sac fry. The bottom materials of both streams are comprised of at least 15% (by volume) particles smaller than 0.84 mm in diam. Streambed gravels containing this quantity of sand, silt and clay do not allow for intragravel water of sufficient dissolved oxygen concentration or velocity to meet the oxygen requirements of developing salmon eggs. Water surrounding eggs planted in Fischer Creek and Little Scarboro Creek had mean dissolved oxygen concentrations of 3.96 and 6.22 mg/liter, respectively. The extremely low mean (2.83 C and 2.67 C) water temperatures of Fischer Creek and Little Scarboro Creek were an added cause of egg loss. In response to low temperature, planted eggs hatched after a prolonged development period of approximately 145 days. Gravel shifts caused by variable stream flow in Fischer Creek may also be responsible for killing naturally deposited eggs there
Selective predation by mink, Mustela vison, on waterfowl
Predation by mink ( Mustela vison ) on three types of ducks (captive, pen-reared-released and wild) was documented in two studies at the Northern Prairie Wildlife Research Center, Jamestown, North Dakota. In the first study, 36 of 60 flightless adult and juvenile ducks held on eight 0.1-acre experimental ponds disappeared between 10 July and 4 August 1969. Available evidence indicated that all were killed by a large adult mink. The mink selected recently released incubator-hatched ducklings, females in the process of incubating, and adults and juveniles on a marginal food supply.In the second study, 152 wood duck ducklings ( Aix sponsa ) were released on a 76-acre marsh during 1971. Half of the ducklings, when 24 to 27 days old, were placed at weekly intervals in four floating pens and allowed to escape after 4 days. Each time birds were placed in the floating pens, a comparable group was placed in a predator-proof shoreline pen. Birds in the shoreline pen escaped as they learned to fly when approximately 60 days old. The shoreline of the marsh was periodically searched, and the remains of 21 (28%) of the floating-pen birds were identified in food remains found at 16 mink dens. No remains of birds from the shoreline pen were found at the dens. Coots ( Fulica americana ) were also taken commonly. Wild ducklings appeared to have been almost totally consumed, but the legs and feet of the wood ducks were often left uneaten because of bands and tags.
Productivity and flowering of winter ephemerals in relation to Sonoran Desert shrubs
Ephemeral plant biomass and density on a Sonoran Desert hill near Cave Creek, Arizona, vary relative to shrub canopy type and shrub density. Higher shrub density associated with increased elevation appears to decrease both ephemeral biomass productivity and density, while ephemeral growth is enhanced under a shrub canopy if it is not too dense or low-hanging. Phenology of ephemerals on the desert study site shows early cool-season germination, low tolerance to heat, and early flowering when compared to shrubs and succulents in the same area.
Growth responses of Spartina patens and Spartina alterniflora by means of a two dimensional factorial design
Growth of Spartina patens and Spartina alterniflora was compared under identical greenhouse conditions. Mature plants were grown in quartz sand and watered with the following solutions: (1) full Hoagland's solution; (2) Hoagland's minus iron; (3) Hoagland's minus nitrogen; (4) Hoagland's with NaCl added to 28 o/oo ; (5) sea water of 28 o/oo . S. patens showed improved growth in Hoagland's solution and Hoagland's minus iron, but showed significantly less growth in solutions 3, 4 and 5. S. alterniflora showed no significant difference in growth in the treatment cultures. General trends which were shown are: (1) S. patens grew better under low iron levels while S. alterniflora 's growth was only slightly enhanced under low iron conditions, and (2) growth of both species was reduced more due to saline conditions than to a lack of nitrogen.
Death feigning by ducks in response to predation by red foxes (Vulpes fulva)
Predation by captive red foxes ( Vulpes fulva ) on approximately 50 ducks comprised of five species was observed in tests conducted at the Northern Prairie Wildlife Research Center, Jamestown, North Dakota. Most ducks were attacked from a rear or lateral position and seized in the cervical or thoracic region. All birds became immobile (death-feigned) immediately when seized and with few exceptions remained motionless during prey-handling and for varying lengths of time thereafter. Initial death feints lasted from 20 sec to 14 min. Recovery was delayed by tactile, visual and, possibly, auditory cues from the foxes. Death-feigning birds appeared alert and often took advantage of escape opportunities. Twenty-nine birds survived initial capture and handling by the foxes. Naive foxes were wary of ducks during initial confrontations, but experienced foxes showed little hesitation in attacking them. After capture, most ducks were taken alive to lay-down sites where they were mouthed and often killed. Then the ducks were usually cached or taken to dens or pups. Several birds were cached alive. Red foxes appear to have adapted to the escape of death-feigning ducks by learning to kill some birds soon after capture and by the evolution of an appendage-severing behavior. Death feigning appears to be a highly developed antipredator behavior of ducks that facilitates the escape of some birds after capture by red foxes.
Status of the wolf in Michigan, 1973
Wolf ( Canis lupus ) numbers in Michigan's Upper Peninsula declined from an estimated 45-50 animals in the mid-1950s to near extinction in 1973, probably because of overharvesting through the bounty system. Sporadic breeding and occasional immigration of wolves from Ontario and Minnesota are postulated to be the factors tending to maintain the present population at the level of perhaps six individuals, with illegal shooting and incidental capture by coyote bounty trappers apparently suppressing it.
Energy allocation patterns of a sprouting and nonsprouting species of Arctostaphylos in the California chaparral
The r- and K-selection theory was used to generate testable hypotheses about patterns of energy allocation in two chaparral shrubs of different reproductive strategies. Terminal-branchlet vegetative and reproductive biomass of the nonsprouting Arctostaphylos glauca and the sprouting A. glandulosa were sampled in a 23-year-old and a 90-year-old stand of chaparral to test the predictions that: (1) the terminal vegetative growth (g dry weight/m 2 of areal coverage) would be equal in the two species, in both stands; (2) oven dry weight (g) of reproductive parts/m 2 of areal coverage would be greater in A. glauca than in A. glandulosa in both aged populations; (3) allocation to reproductive parts by the shrubs in the 23-year-old stand would be greater than (or equal to) that of the 90-year-old shrubs. The amount of terminal vegetative growth was equal for both species in the 23-year-old and the 90-year-old stands. There was no statistically significant difference in the weight of fruits produced by the two species in the 23-year-old stand. However, fruit production by A. glauca was significantly greater than by A. glandulosa in the 90-year-old stand. Fruit production was also significantly greater for the older A. glauca shrubs than for those in the 23-year-old stand. The relationships of rainfall pattern and age of shrubs to fruit production are discussed.
Return of the gray wolf to Wisconsin
Five gray wolf ( Canis lupus ) specimens were examined from Wisconsin from 1975 through 1979; each had been killed by human beings, accidentally or intentionally. This confirms the presence of wolves in Wisconsin and supports the hypothesis that human-related mortality is the factor limiting the population.
Reproduction of raccoons (Procyon lotor) in North Dakota
Necropsies and observations of captive and radio-equipped individuals provided reproductive data from a raccoon population in the northern prairies. The mean parturition date of adult females was 8 May and the mean litter size was 4.8. Only two of the 14 yearling females examined prior to 1 July were pregnant; they had estimated parturition dates of 20 May and 22 June. Penes of most yearling males became extrusible in July or August. Testes weights and sperm smears suggest that yearling males in North Dakota are not reproductively active. Reproductive patterns of raccoons near the northern periphery of their range and those at lower latitudes are compared and discussed.