MER AS at aot . Reet rae Oe eee Uae a ereney ee RH o get ectetehe A Sahel = =¥ ca aa 7 4 a e ae i a: State of Illinois Dwight H. Green, Governor Department of Registration and Education Frank G. Thompson, Director PRELIMINARY REPORT ON THE CANADA GEESE OF THE MISSISSIPPI FLYWAY Harold C. Yanson and Robert H. Smith Published by Authority of the State of Illinois Natural History Survey Harlow B. Mills, Chief Biological Notes No. 18 Urbana, Illinois September, 1947 a re Lane Pg gut yd wn if pGsitmowit: Sta’ me saad iaiges baat Paid moged | he Felt BT ules oy inal te HOLT GA PRELIMINARY RFrORT ON THE CANADA GEESE OF THE MISSISSIPPI FLYWAY Harold C. Hanson and Robert H. Smiths That the sound management of waterfowl and other wildlife species must in the last analysis rely on carefully gathered scientific data is axiomatic. Because the range of most waterfowl species is immense, and because some popula- tions shift their distribution within a flyway from year to year as a result of changing food, water, and weather condi- tions, adequate scientific data from all parts of the range are difficult to secure. The present paper on the Canada geese of the Missis- Sippi Flyway is a preliminary report of a study that represents combined efforts said support of six agencies: the Natural His- sires patna Fuariaier of the Illinois State Department of Registra- tion and Education; the U. S. Fish and Wildlife Service; the Pi eis State Department of Conservation; the Lands, Parks, and Forests Branch of the Canadian Department of Mines and Resources; the Jack Miner Migratory Bird Ficwusiecdcral, ies and the Arctic Institute of North America, Biologists of these agencies have studied the Canada goose of the Mississippi Flyway at most of its important con- centration points from Hudson Bay to the Gulf of Mexico. An *% Harold C. Hanson, Assistant Gane Specialist, Illi- nois “atural History Survey; Robert H. Smith, Flyway Biologist, U. S. Pish and Wildlife Service. at SE intensive study and banding program has been carried out at the important wintering area centering on Horseshoe Lake, Alex- ander County, in southern Illinois, where the Illinois State Department of Conservation maintains a game refuge. Because printing difficulties and a shortage of suit- a able paper give promise of further delays in publishing the final report on the study, the present preliminary report is issued at this time. Issuance of this report now will make possible the inclusion in the final report of data and infor- mation derived from an additional year of study. . Status of Mississippi Flyway Geese ee ee In 1946, 14 states of the Mississippi Flyway (Michigan, Wisconsin, “innesota, Ohio, Indiana, Illinois, Iowa, Xentucky, Tennessee, Missouri, Mississippi, Alabama, Arkansas, and Louisiell ana) rere closed to the hunting of Canada geese. The closed Season of an entire figway was the firat of its iid his tory of this species of waterfowl. The only similar actions woe those eecene the shooting seasons on snow geese and brant — in the Atlantic Coast states. Snow goose hunting has been pro- hibited there since 1931, and brant hunting for 9 of the 15 years since 1933. | Closing the season on Canada geese in the Mississippi i Flyway was necessary for a number of reasons; a pee ce decrease j in the number of these geese in tor flyway from 144, 843 in 1940 ; wot vis? to 72,770 in 1945; increased kills beginning in’ 1939, partic- ularly in the region of Horseshoe Lake; a disproportionate kill of juvenile birds and an apparent decreased productivity in 1945, as indicated by research at Horseshoe Lake. Tables l, 2, and 3 present detailed figures on this situation. The number of geese wintering at Horseshoe Lake dropped from about 50,000 in 1943-44 to 26,000 in 1945-46. That this decrease represented a real decrease in the flyway population and was not due to by-passing of the area by flocks is shown not only by flyway censuses but by band recovery records; these records indicate that since 1932 many of the geese that formerly used the Mississippi from Cairo, Illinois, to Baton Rouge, Louisi- ana, have concentrated in a much smaller area centering on Horse- shoe Lake, because of the refuge there and the large anount of grain made available to them. f Calculated total kill figures indicate that in each of the recent hunting seasons between 23 and 46 per cent of the available Canada goose population in the Mississippi Flyway was shot. In view of the known relatively low productivity potential of the Canada goose, it was obvious that the birds could not stand a high kill. Recent population declines in the Mississippi Flyway showed that flock mortality from all causes combined had been excessive, and, as hunting losses are one type of mortality that can be controlled, it was evident that closing the flyway to shooting was the most effective management measure that could have been employed. ; ae ee Evidence: of increased shooting pressure on Canada geese in recent years is shown by lowered survival rates, as computed from band recoveries by hunters; these recoveries are from geese banded at the Jack Miner bird Sanctuary, Kings- ville, Ontario, and the Horseshoe Lake Game Refuge, maintained by the Illinois State Department of Conservation. Eanding data on.Horseshoe Lake geese show that the survival rates of the 4 flock wintering there are below the averages for other popula- tions in the flyway. 4 | | . Contributing to the recent heavy kill of birds in “the Horseshoe Lake area was an apparent alteration in the habits of the geese wintering there, In recent years the birds have lacked the wariness. usual in the Canada goose. Although this goose possesses a natural wariness that has given it a high survival rate under primitive conditions, individuals os 5 unable to solve problems of self-preservation that arise ina greatly modified environment such as that at Horseshoe Lake. During recent hunting seasons there, the geese exhibited an almost complete disregard of gunfire, flying back day after day to fields that were heavily shot. Calculations based on the sisi yall series obtained for the Horseshoe Lake flock indicate that only 12 per cent of the juveniles lived long enough to raise a brood of young. When a major portion of the annual kill of a Canada goose flock is at the expense of one age group, data on ten ne Mest total number of birds bagged do not reveal the true impact of the kill upon the future reproductive capacity of the population. At Horseshoe Lake the juveniles made up the major part of the kill from the time this study began in 1940 until shooting of the Canada goose was stopped in the Mississippi Flyway at the end of the 1945 season, table 3. A year of low productivity in Canada geese should be of particular concern to the administrators who regulate the kill by. hunters, for the reason that the young birds bear a double responsibility. Being more vulnerable to shooting than the adults, they must contribute a disproportionate share of the kill, and, secondly, they must. survive in sufficient nun- bers to reproduce an equivalent of the annual loss in yearlings and the breeding population. . Even in a year when the production of young was not significantly low, 1943, shooting losses in the Horseshoe Lake area were so severe and so greatly at the expense of the juveniles that only a small proportion of this generation survived to reach the minimum breeding age of @ years. Management What can be done to insure the future of the Missis- sippi Flyway geese? Until recent years, the two prime measures for conserving waterfowl (refuges and hunting regulations) have Pia: hese .usually been fairly successful in the management of this group. With the population of geese dealt with in this report, it is apparent that since 1939 these measures as applied have not : been very effective. There is little that can be done to limit the kill , 4 { } i | 4 ; | of geese in Canada, because much of it is virtually necessary for the survival of the native Indians. In 1944 and 1945, when season limits were imposed for Alexander County, it was a relatively easy matter to limit the Fane Of geese in the Horseshoe Lake area to a predetermined fig- ure, due to the facility with which the day-to-day kill could be tallied. The season bag limit in the above instances was determined by the trend of the population in prior years, but, to be fully effective, management should anticipate future trends based upon the current composition of the population. With the data at net on the Canada goose in the Mississippi Flyway, it is possible to arrive at a pracviea” estimate of the © maximum kill that can be tolerated. Since the fall flicht in any year depends to a large extent on the production of young in the spring of that year, to predict the flock population with reasonable accuracy, it is necessary to know the trends in numbers of breeding females and to have some measure of the nesting success on the breeding © grounds. Inventory on the latter is not. easy because of the | nature of the terrain, but the use of planes aids tremendously in such work. For the present. and until more data are availabl - 8 « the average productivity bf He flyway population mizht be cal- culated on the basis of four young (brought to flying stage) per adult female. | | If the flock population has been fairly stable for several years, a 10 per cent kill in the Horseshoe Lake area might prove to be within the limits of what the flock could stand without decreasing in size. Even this kill might be too high if kills north of Horseshoe Lake were unusually large in a given autumn, if nesting success was low the previous spring, or if sex and age ratios were seriously unbalanced. The kill of a single pihae*hewavet, when the population is very low con- stitutes évershooting. A reduction in the crippling loss would increase the permissible retrieved kill in the Horseshoe Lake area. The number of geese crippled and lost to hunters each year in the area is needlessly high. An estimate of cripples not retrieved, and later dying, is placed at 30 per cent of the retrieved kill. Certain SGnintstrative measures can be taken to reduce the per cent of cripples not retrieved, but the larger share of the re- sponsibility rests with the hunter himself, who must restrain the natural desire to "give a high one a ride." Greater spacing of pits to reduce competition among hunters micht aid in re- ducing crippling losses. Many hunters hope to bag geese with greater ease by using magnum shotguns. Yowever, it is debatable whether more geese are bagged than crippled by such guns because of the out-of-range shooting their possession encourages. = gt: ee The hunting restrictions most frequently used to re- duce game kill to the desired level are simply a reduction in the length of the season or a further limitation of the bag. A study of kill and of hunting EE ens the Horseshoe Lake area shows that hunting restrictions were not always suc- eessful in reducing the kill to the desired extent, but, if various measures instituted to lower the annual kill had ait been taken, it is probable that a large proportion of the Canada geese using the Horseshoe Lake area would have been shot by the end of 1946. It is ieee that the eetes kill at Horse- shoe Lake needed to be restricted in a drastic manner, pagent ‘the flock had lost so much of its natupal wariness and become so vulnerable to hunting. In 1945, for example, there were only 5 half days of shooting, but the kill was, nevertheless, 5,200 bagged, another 800 to 1,000 crippled, plus lesser losses from miscellaneous causes, 3 Pirnie (1939) has emphasized that "Changing habits of See (geese) may create new hazards for them and require even more stringent regulations." The behavior of the Horseshoe Lake flock in recent years and its relation to shooting pee | already been discussed, but it should again be empiaa i ged that restrictions alone cannot be expected to safeguard it. Refuges form an important part of our system for the preservation of waterfowl. Whether or not any individual refuge peewee of eee will dapend to a certain extent upon its manage= ment and also upon its size. Leopold (1931) stated the chief - 10 = problem in regard to the Horseshoe Lake Game Refuge soon after this refuge was created. "The question of whether public refuges should be surrounded by public shooting grounds is frequently debated. Horseshoe Lake in Alexander County, Illinois, is a good place to study the question." The present food resources of the Horseshoe Lake Game Refuge are insufficient to winter more than 10,000 geese, and probably only 5,000 can be accommodated to best advantage. When the corn crop and wheat browse on the refuge are exhausted, and occasionally before this occurs, the flock feeds on unhar- vested and sometimes standing grain in the surrounding country- side -- occasionally at a considerable loss to farmers who do not rent their fields to hunters. The breakdown in wariness that has occurred is per- haps more serious to the future of the Horseshoe Lake flock than the reduction of its size. It is