Showing papers in "Journal of Wildlife Management in 1956"

A Simple Field Candler for Waterfowl Eggs

Abstract: In nesting studies of waterfowl and other game birds it is often desirable to determine the stages of incubation of clutches of eggs. This information makes it possible to determine when incubation began and to calculate the date of hatching. In some studies, the stage of incubation has been determined by breaking an egg of each clutch. This is an unnecessary waste, and for species which lay parasitically in other birds' nests, such as the redhead and ruddy duck, the breaking of one egg has little value because eggs in a single nest may be in many stages of incubation. Westerskov (1950) discussed the need for age determination of embryos and presented several methods which he used in the laboratory in working with pheasant and European partridge eggs. These methods were weighing, floating, and candling of eggs. The use of egg weights in the field necessitates carrying a delicate balance and making calculations from the weights in order to determine the stage of incubation. In the second method, eggs are floated in water; their buoyancy and position are related to the stage of incubation. While this method is satisfactory for use in the laboratory or for species which nest over water, it is inconvenient for land nesters. This technique permits rapid age determination in the early stages of incubation but becomes less accurate as incubation progresses. By the use of a laboratory candler, Westerskov found that the size of the air cell and the early development of the embryo were good criteria for determining the stage of incubation of pheasant eggs. The increased density of the yolk mass plus the opacity of the shell reduced visibility so that the embryo could not be seen properly after the first week of incubation; but the size of the air cell proved an excellent criterion throughout. The use of the air cell in candling chicken eggs has been reported by many workers, including Banner (1920), and Lamon (1921). Candling has been little used in the field because of the lack of simple and efficient equipment. Evans (1951) used a cardboard mailing tube for candling duck eggs in the field; from the comparative size of the air cell, he determined when the eggs were near hatching. Hanson (1954a) developed a battery-operated field candler which provided excellent visibility of many details of the egg. He presented a list of criteria and photographs of eggs at various stages of incubation (1954b). In order to develop criteria by which the stage of incubation of duck eggs could be determined in the field with the simple mailing tube suggested by Evans, the present study was initiated in the spring of 1952. Twenty-six redhead, ten canvasback, five pintail, and five mallard eggs were candled when brought into the hatchery, found to be fresh, and were placed in an incubator. The development of these eggs was followed with the mailing tube candler.

Evaluation of the Pellet Group Count as a Deer Census Method

Abstract: Reliable estimates of deer numbers are basic to effective deer herd management. Michigan's first large scale "any-deer" season in 1952 led to intensive study of available methods of estimating deer population levels. Results of some experimental investigations concerning the potential value of pellet group counts as a deer census method are presented here. The method was described by Bennett, English, and McCain (1940) and has been subsequently used by a number of investigators. However, only a limited amount of checking has been done on basic assumptions. Perhaps one of the best possible checks on the method lies in its application to an area containing a known deer population. The purpose of this paper is to report such a test and initial results of studies concerning daily defecation rates and rates of pellet deterioration.

Relationships between the chemistry of minnesota surface waters and wildlife management

Abstract: Relationships between chemical quality of fresh waters and associated geological, climatic, and biological phenomena have long been of interest to aquatic biologists. Minnesota is especially favorably located for such observations because of varied climate and geology and a resulting wide range in the chemical quality of surface waters. Studies of regional water chemistry of Minnesota lakes have been carried out in Minnesota since 1935 and, as has been reported earlier (Eddy, 1938; Moyle, 1945), patterns of water chemistry are evident that are associated with biological patterns. The relationships noted are general and geographic in nature and should be applied with caution to individual waters. Water

Experiments on causes of duck nest predation1

Abstract: The observer-approach method of conducting waterfowl nesting studies has been criticized and defended in turn by many individuals concerned with waterfowl research and management. The main objections have been: (1) the tracks and trails made by the observer are apt to lead predators to the nest; (2) nest markers may furnish clues to certain egg-eating birds and mammals which will result in increased

Effect of a Slash Burn on Forest Mice

Abstract: A discouraging aftermath of the clear-cutting of virgin forest in the Douglas-fir region of northwestern California is the enormous accumulation of waste slash. When loggers finish their work, they leave the ground cluttered and strewn with interlocking tangles of branches and tops of conifers, splintered trunks, shattered sections of bark, great piles of culled logs, and entire trees of madrone (Arbutus menziesii Pursh) and tanoak ( Lithocarpus densiflorus [Hock & Am.] Rehd.), uprooted or smashed.

Productivity of Canada Geese in the Flathead Valley, Montana

Abstract: Published studies of productivity of the Great Basin Canada goose (Branta canadensis moffiti) include those made in Utah (Williams and Marshall, 1937, 1938), in Wyoming (Craighead and Craighead, 1949), and in California (Dow, 1943; Naylor, 1953; Miller and Collins, 1953; Naylor and Hunt, 1954). Although these studies have made it possible for waterfowl managers to estimate productivity of goose populations with some confidence, they have been incomplete in one or more respects. In most cases the studies have been based on samples of the breeding population in areas where the nonbreeding element was not definitely known, thus making it impossible to estimate the productivity of the total population with certainty. Because of the difficulty of determining gosling mortality, productivity has been estimated from the number of young hatched rather than from the number of young reaching harvestable age. Also, the extent of renesting and its compensatory effect has not been considered.

Snow Depths and Ungulate Abundance in the Mountains of Western Canada

Abstract: It is long established that "severe winters," or "'hard winters," cause fluctuations in ungulate populations. Annual reports of the British Columbia Game Department have noted since 1912 that such winters may cause serious declines. Roe (1951) reports "hunters' traditions" as early as 1875 attributing bison decreases on the American prairies to severe winters. Published accounts of ungulate mortality due to severe winters or deep snow involve a wide range of species in a large geographic area. Holzworth (1930: 23) notes that blacktailed deer on the islands of southern Alaska die in thousands during severe winters. Spiker (1933) considers deep snow as the only important factor in winter mortality of Adirondack white-tails. Rand (1947) concludes that severe winters with deep snow are the worst enemy of pronghorn antelope in Alberta. Murie (1944) records heavy losses in Dall sheep, and in moose, during severe winters with deep snow in Alaska. Roe (1951) quotes numerous historic references describing American bison declines because of snow, but discredits most of them in support of his thesis that man, not snow, was the bison's chief enemy. Cowan (1950) records a cold winter with deep snow that reduced mountain goat survival in the Canadian Rockies, and later (1952) calls winter the greatest enemy of goats. The latter paper also postulates the near extermination of elk in the Rocky Mountain region as a result of severe winters in the 1870's and in

Observations on Factors Affecting Smallmouth Bass Production in Iowa

Abstract: Many states in the range of the northern smallmouth bass ( Micropterus d. dolomieui) have in recent years conducted, or are at present conducting, studies on various factors in the life history of this species. Fleener (1952) in Missouri, and Larimore (1954) in Illinois, worked on the effect of artificial stocking; Gerking (1953) in Indiana, and Larimore (1952) in Illinois showed evidence of the homing instinct or behavior; and Webster (1953) worked out the patterns of dispersions and movement of the smallmouth bass in Cayuga Lake, New York. In the streams of northeast Iowa, the smallmouth bass is considered a major fisheries resource. With the accelerated fishing tempo directed against this species in the last decade, the characteristic instability of stream populations of the smallmouth bass has become increasingly apparent. In 1949, a study of factors that could potentially influence natural reproduction and survival was begun. In addition, efforts were directed toward developing a simple method of censusing both the adult and the young-ofthe-year segment of a stream population. In 1949, a series of 17 representative smallmouth bass streams were chosen and annual

Changes in Norway Rat Populations Induced by Introduction of Rats

Abstract: The introduction of aliens into an existing population of mammals may be followed by unexpected effects that relate to social structure and population composition. These effects were studied by introducing alien rats into stationary and increasing populations of rats in city blocks. This work is part of a continuing study of the mechanisms of change in vertebrate populations using Norway rats (Rattus norvegicus) in residential areas in Baltimore as experimental animals (Davis, 1953). These rats inhabit back yards, basements, and garages and feed on garbage. The human sanitary conditions in general are poor and remain unchanged for months at a time, so that the food supply of the rats has only slight seasonal variations. Other environmental conditions are similarly subject to little change for many months at a time. The constancy of these factors permits experiments on populations in a relatively stable environment. Finally, the population of rats in each block is essentially discrete and isolated, as rats rarely travel from one block to another (see Davis, 1953, for references). METHODS AND PROCEDURES

Nesting Study of Wood Ducks

Abstract: Shortly after moving into a new home along the Mississippi River just north of Minneapolis, I became aware of several pairs of wood ducks nesting in hollow basswood trees on the nearby river banks. This extreme accessibility of the birds induced me to begin a study of certain phases of the nesting activities of the birds. A nest box was accepted by them in 1947. Later this box was reconstructed with a "floating" floor and an alarm clock-cake pan recording apparatus as shown in Figure 1. This mechanized box was occupied by a wood duck, possibly the same female, for the three succeeding seasons, 1948, 1949, and 1950. She was not banded during the earlier part of the work since it was feared she would be seriously disturbed or might even desert her nest as a result, and the recording of nesting data seemed more important than the banding of the bird. She was finally banded just before the young left the nest during the spring of 1950. At first only the nesting rhythm or peri ds of nest attentiveness were recorded and studied. Later some thermocouple temperature readings were taken as a check on the effectiveness of the down

Trapping Techniques for Ruffed Grouse

Abstract: Population research on ruffed grouse (Bonasa umbellus) has been handicapped in the past because it has been virtually impossible to live-trap adequate samples. Fundamental information on movement and longevity has been practically unknown for this species. To manage this important game bird intelligently a knowledge of its population dynamics is essential. Therefore effort was made in Wisconsin to develop effective live-trapping methods. This paper will describe the trapping techniques we are using currently for handling ruffed grouse in spring, fall and winter.

Watering patterns of some desert game animals.

Abstract: In recent years wildlife administrators in the arid southwest have expended much time and money in developing watering places on desert ranges that contain all of the essential habitat requirements for the production of game except for permanent and available water. Some developments are designed primarily for use by quail and other game birds (Glading, 1947). Access to water is restricted to small game by covered ramps and stockproof fences. Other developments are designed for multiple use by game mammals as well as birds (Halloran, 1949). From June 1951 to January 1953, I carried on a field study of several man-made, multiple-purpose, game-watering places with the following objectives: (1) to determine the species of desert wildlife utilizing man-made tanks, and to determine where possible which of those species are dependent on them to satisfy their water requirements; (2) to determine daily and seasonal utilization patterns by the different species; (3) to study behavior of different species at water; and (4) to evaluate waterhole counts as a census technique. I obtained utilization data on ten species of mammals and 25 species of birds. Because of space limitations, the present report will consider only the following important game species: mule deer (Odocoileus hemionus), javelina (Pecari angulatus), white-winged dove (Zenaida asiatica),

Age determination and dating nesting events in the willow ptarmigan 1

Abstract: A thorough knowledge of sex and age ratios and the nesting phenology of game birds has become an integral part of modern game bird studies. The consistent and regular moult of the primaries in game birds has proved valuable in facilitating the assembling of comprehensive data on nesting events when the moult pattern is understood. This regular wing moult pattern was first described and used as an accurate aging method by Bureau (1911) for the common partridge, Perdix perdix, and the red-legged partridge, Alectoris rufa (1913). In later studies, the wing moult and its use in age determination and dating of nesting events have been described for the bobwhite quail, Colinus virginianus (Petrides and Nestler, 1943; Thompson and Kabat, 1950; Petrides, 1952; and Reeves, 1952); the pheasant, Phasianus colchicus (Buss, 1946; Kabat, Thompson and Kozlick, 1950); the ruffed grouse, Bonasa umbellus (Bump et al., 1947; Hale and Wendt, 1951). McCabe and Hawkins (1946) added further data on the wing moult of the partridge; Thompson and Taber (1948) were the first to use wing moult data for producing reference tables for dating nesting events in pheasants, partridges and bobwhite quail. A similar reference chart for dating nesting events in the willow ptarmigan, Lagopus lagopus, is presented here as an aid in assembling nesting data. Whereas much material on the nesting of the willow ptarmig n is available in the Norwegian literature, very little is known and recorded about t breeding of this bird in Canada and Alaska.

Foods Eaten by Bobcats in Maine

Abstract: Any one of the counters may be picked off and used individually or may be used while on the magnet. The entire unit may easily be shifted to the most convenient location in the vehicle or moved into another car or airplane. The counters or magnet may be labeled, or the positions of the counters memorized to facilitate recording while looking th ough binoculars. Counters made of plastic, aluminum and some alloys will not adhere to a magnet. Those used in this study have st el cases which are held firmly in place during the roughest travel.

The Pike, Esox lucius Linnaeus, in Relation to Water-Fowl on the Seney National Wildlife Refuge, Michigan

Abstract: In these areas it was estimated that approximately 10 per cent (about 1,500,000 individuals) of such birds were destroyed by pike in an average year. In the early years of flooding of the pools on the Seney National Wildlife Refuge (1936 to 1941), concern was felt over the subjectively determined slow increment of the avian population as compared to that of pike, and led to the obvious question of how great a limiting factor the fish were in duck production. The problem of utilizing the obviously extensive pike resource for public enjoyment was also considered, even to the extent of using angling as a method to reduce the fish population if such control seemed desirable. The

Age Determination of Foxes by X-Ray of Forefeet

Abstract: An investigation of breeding, denning and range of the red fox (Vulpes fulva) and the gray fox (Urocyon cinereoargenteus) in Alabama provided an opportunity to record certain age characteristics. Emphasis was placed on the possibility of identifying young of the year among older foxes by the condition of the epiphyses of the bones in the forefeet as determined by X-ray. Similar X-ray studies of the upper tibial epiphysis of dogs (Schlotthauer and Janes, 1952, Amer. Jour. Vet. Res. 13(46): 90) have indicated that the "lower femoral and upper tibial epiphyses close at about the age of 10 months." Two foxes, a red and a gray, were available for these studies during the first fall (1952) of the investigation. The approximate age of each fox was known since they were captured while small. X-rays of the lower radius and ulna of these foxes were made at intervals (Table 1, Animals 2134 and B). The first two X-rays (October and November) showed that cartilage still separated the epiphyses on the radius and ulna from the diaphysis or shaft. The December X-rays showed the epiphyseal plate beginning to disappear but not completely ossified. Unfortunately the red fox escaped in December. An X-ray of the gray fox in early January showed the epiphyses of both the radius and ulna completely ossified. The following fall two young red foxes and two young gray foxes were used in similar X-ray studies. One of these red foxes also escaped before the investigation was completed. X-rays late in December of the remaining red fox and the grays showed the epiphyses almost completely ossified. X-rays of the fore-feet of seven foxes of unknown ages in January and February showed the epiphyses of both the radius .and ulna completely ossified. It appears that foxes can be classified dependably as adults or as young of the year through November by means of X-rays of the distal epiphyses of the radius and ulna (Figure 1). Some young foxes were distinguishable through most of December. This indicates that ossification is completed in foxes between eight and nine months of age. A faint and incomplete line along the epiphyseal plate is still visible on some foxes in January at which time they are approximately 10 months old. Whelping of foxes in Alabama occurs primarily during late March and April (Sullivan, 1953, M.S. Thesis, Alabama Polytechnic Institute). To test this technique, 60 fox feet were secured from trappers who were trapping for bounty in connection with a fox control campaign in Lee County, Alabama. Most of these foxes were trapped at or near dens in late summer and fall. The feet were first preserved in alcohol-formalin solution, then dried and pinned on cardboard squares of the same size as the X-ray negatives to be used. As many as 25 feet were X-rayed at one time. By studying the X-rays, it was a simple matter to separate the adult foxes from young of the year. Forty-four (73 per cent) of the 60 foxes were juveniles. Subsequent experiments showed that fox feet can be dried fresh without preservative and kept for several months before they are X-rayed. The clearest egatives were secured when the feet were layed directly on the film holder and X-rayed without being first pinned to cardboard. The foreleg when removed from the fox should be cut off above the joint at the pad, preferably halfway up on the first long bones (radius and ulna). Successful X-rays were made on "Kodak (no screen) safety film No. 246" with exposures of 60 KVP at 20 MA at one-half-second. All exposures were made at 36". Personnel of the Small Animal Clinic of Alabama Polytechnic Institute did the X-raying. By X-raying fox feet collected from trappers through November, biologists can determine the ratio of young to old foxes harvested. The final date for collecting feet in different regions should be not later than eight months following the earliest whelping of fox pups in that area. Information on percentage of young should provide a better understanding of productivity of the fox. This technique has two principal advantages: (1) it permits determination of age without having the entire carcass in hand, and (2) it permits accurate determination of the ratio of young of the year to older foxes for about three months longer 1 A contribution from the Alabama Cooperative Wildlife Research Unit; jointly sponsored by the Alabama Department of Conservation, Alabama Polytechnic Institute Agricultural Experiment Station, the U. S. Fish and Wildlife Service, and the Wildlife Management Institute.

Regional Differences in Size and Productivity of Deer in West Virginia

Abstract: West Virginia deer hunting was regulated by a buck law during the four decades prior to 1951. One of the consequences of this regulation was development of excessive deer populations in certain parts of the state. An investigation of problems associated with rapidly increasing deer populations was established by the Conservation Commission in 1947. This work was undertaken with Pittman-Robertson funds. The project has now been active continuously for eight years in many phases of life history and management of deer. The phase reported here has the following objectives-to study deer range potentials as indicated by physical development of deer, and to compare skeletal growth, body weight, antler development and breeding potential of the deer comprising various herds in the state. Before this study was established it was recognized that there were distinct differences in size and productivity of deer between various parts of West Virginia but the magnitudes of these differences were unknown. Information about physical characteristics and productivity may be useful in many ways. Some of the values with respect to productivity were expressed by Morton and Cheatum (1946) as follows: "Knowledge of the breeding potential of a game species is essential to its proper management. Regional differences in productivity may demand differences in diagnosis and treatment. In the whitetailed deer (Odocoileus virginianus), proper management may require adjustments in laws relating to bag limits, open seasons, and legal game (buck, antlerless, and 1-deer laws). In cases of low fecundity, efforts to adjust the environment to increase the number of young produced may be feasible. These matters should be considered in the formulation of policy intended to make the best possible use of game resources." A direct relation has been observed between adequacy of forage and ability of female deer to produce and rear fawns. Gerstell (1938) noted low fawn production in sections of over-browsed deer range in Pennsylvania. O'Roke and Hamerstrom (1948) reported a similar relationship for the George Reserve deer herd in Michigan. Inv stigations conducted in New York by Morton and Cheatum (1946) and by Cheatum and Severinghaus (1950) have produced evidence that fertility and fecundity of deer are directly related to range quality. Information on anatomical characteristics of deer may also indicate range quality. Severinghaus et al. (1950) presented evidence that variations in antler development are related to forage adequacy. Differences in body weight and/or antler development were attributed to differences in range conditions by Johnson (1937), Gerstell (1938), Park (1938), Park and Day (1942) and Leopold (1943). In West Virginia, reduction of a high deer population resulted in a significant weight increase among fawns killed in the same area the next year (Gill, 1953b). Most of the foregoing authors cited inadequate quantity of forage during winter as the cause of reduced size and/or productivity of deer. Recently Dunkeson and Murphy (1953) reported a direct relationship in Missouri between soil fertility and body weight, antler development, and reproductive potential. Differences in size and productivity of West Virginia deer may also be related to differences in quality rather than quantity of forage. In this state deer population increases were controlled before any extensive ranges became overbrowsed. Population control was secured by adoption of hunter's-choice deer seasons beginning in 1951. Deer of either sex have been 1 Now with Maine Game Division, E. Annex, Univ. of Maine, Orono, Me.

Effects of Exploitation on a Marten Population

Abstract: The problem of evaluating the status of animal populations was encountered during a fur resource survey 2 in the Fort Nelson region of northern British Columbia. This paper deals with the possibility of analyzing catch records in order to evaluate the effects of exploitation on a population of marten (Martes americana actuosa). Marten specimens were collected from registered trap lines in an area of about 20,000 square miles during two trapping seasons, 1947-48 and 1948-49. These specimens totaled 127 and 123 in respective seasons and constituted about 16 per cent of the known kill for each year. Additional information useful for the interpretation of kill records was obtained in the field as reported by Quick (1953). The recent history of fur production in this region suggested that the trapping pressure was not detrimental to the population. Although a high level of fur production continued through at least eight years the gross production data did not provide a means of interpreting the status of the population or the effects of trapping pressure on the fauna. Data obtained from separate trap lines within the region revealed some variations that suggested the possibility of analyzing trapping pressure. One of the important population characteristics, sex ratio (of the kill), was readily determined. Variations in the sex ratio of the kills made by different trappers demonstrated that the timing of trapping operations resulted in selective sampling of the sexes. This has been reported in preliminary form (Quick, 1953). Another important population characteristic, age class determination, has not been satisfactorily worked out for the marten but Marshall (1951) has made progress on this subjec . The degree of development of the sagittal crest as an age class criterion has been described by Marshall and others. The sagittal crest characteristic was used in this study to classify marten skulls into groups (Table 1). Sagittal crest measurements were