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DEVELOPMENT OF MANAGEMENT STRATEGIES FOR MALLARD AND CANVASBACK Region 6
Materials used in support of presentation by Robert L. Croft at Project Leader's Meeting January 18, 1983 . -- •
TABLE OF CONTENTS
Page
Introduction 1 Di stri buti on 1 Statement of Reponsibilities 1 Supply and Demand Mallard 4 Canvasback 5 Objectives Mallard 5 Canvasback 5 Definition of Problems Mallard 6 Canvasback 6 Analysis of Causes and Consequences Mallard 6 Canvasback 10 Description of Strategy Elements Habitat Development 12 Habitat Development off Service Lands 15 Management of Predation 17 Increase High Protein Foods (Service Refuges Only) 20 Habitat Preservation 20 Population Surveys 23 Research and Development 24 Disease Management 25 FWS Administration 26 Preliminary Screening 27 Characteristics of Affected Publics 28 Sources of Information 28 DEVELOPMENT OF MANAGEMENT STRATEGIES FOR MALLARD AND CANVASBACK
INTRODUCTION
This paper summarizes accomplishments from Regional Resource Planning efforts concerning the mallard (Anas platyrhynchos platyrhynchos) and the canvasback (Aythya valisineria) due~ The purpose is to provide a bases for developing four or five strategies to test, using the Mallard Management Model, for accomplishing the population objectives for mallards and canvasbacks in Region 6. To develop these strategies, a list and description of potential strategy elements is given. Our intent is to identify all potential strategy elements regardless of their cost or practicability for use in developing the test strategies. We need your help to review and to add potential strategy elements (management techniques) to this list. There are approximately 25 times more breeding mallards than canvasbacks in Region 6. It is our judgement that public demand requires the mallard to be the lead species for strategy development. Canvasback breeding habitat requirements are more precise than for the mallard. Therefore, canvasback strategies will be incre al add .tions to those strategies identified best for mallards. ",;)~ ~ ~ -t-- ~ ~ -8-, c-. ~ The Service's responsibilities, objectives, problems and rationale for the above actions are also present. DISTRIBUTION: The approximate distribution of breeding mallards and canvasbacks is given in Table 1. Figure 1 should be the location of Strata in Montana, North Dakota and South Dakota. The density by strata are based on a 10-year average breeding population for mallards and canvasbacks in the three States. The Regional objective is calculated by multiplying that porti on of the surveyed area (18.5 percent) within Region 6 in the Waterfowl Breeding Survey by the National objective (8,000,000 and 625,000 breeding mallards and canvasbacks, respectively). STATEMENT OF RESPONSIBILITY: The U.S. Fish and Wildlife Service is responsible, under the Migratory Bird Treaty Act, for the preservation, distribution, reintroduction, and restoration of game birds and other wild birds. The Animal Damage Control Act of 1931 authorizes the Service to resolve conflicts, usual ly crop depredation, between man and wildlife. Table 1. Distribution of 10-year Average of Breeding Populations of Mallards and Canvasbacks in Region 6 Compared to Land Area and Objective by State and Strata. Mallards (thousands) Canvasbacks (thousands) Square 197 2-81 197 2-81 State Stratum Miles Average Objective Average Objective
Colorado 103,948 30 34.7 Kansas Tr Montana 353.9 419 .o 7.7 16.0 41 32,902 201.3 238.3 5.7 11.8 42 40,755 152.6 180. 7 2.0 4.2 Nebraska 76,612 42.0 48.5 North Dakota 512.8 608.0 33.2 69.0 43 19,835 122.1 144.8 3.0 6.2 45 26,625 277. 7 329 .2 23.3 48.5 46 14,238 96.0 113.8 6.9 14.3 47 7,821 17. 0 20. 2 0.0 South Dakota 382.5 453.0 9.3 19.0 44 27,299 144.0 170. 5 1.9 3.9 48 24,587 167 .4 198. 3 5.8 11.8 49 15,830 71.1 84. 2 1.6 3.3 Wyoming 97,914 67. 0 77 .4 Utah Tr 1
1 No figures to establish objective
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f" i 4 Canvasback The demand for hunting exceeds the available supply of canvasbacks. The canvasback has high symbolic value among waterfowl enthusiasts for its sporting tradition and aesthetic qualities. In many regions of the U.S. and Canada, hunting opportunities are limited by regulations currently in use to reduce the harvest of canvasbacks. Hunters want to increase canvasback numbers and reduce harvest restrictions (open closed areas and reduce point value). This bird is important to photographers, wildlife artists and bird watchers. The distribution of consumptive and nonconsumptive demands and the availability of canvasbacks are virtually the same. It is assumed that if the consumptive demand is met, the nonconsumptive demand will be exceeded. In Region 6, it is estimated that the breeding population of canvasbacks is about one half as large as it should be. This estimate is based on availability of breeding habitats within Region 6 compared to habitats in other portions of the canvasback breeding range. Biological needs may become an important consideration for this species because breeding habitat has been virtually eliminated in a large portion of its original breeding range in Region 6. Canvasbacks need specific combinations of wetlands, from seasonal to permanent ponds of various sizes and water quality to successfully hatch and fledge ducklings. Dra i nage of prairie potholes continues and inappropriate tillage of steep slopes in the Missouri Coteau is causing severe erosion. Resulting siltation is also destroying breeding habitat. OBJECTIVES: Mallard In Region 6, the objective is to increase the mallard breeding population, by 1990, within Waterfowl Breeding Bird Survey Strata 41-49 from 1.25 to 1.48 million breeding birds with the following distribution: Montana, 419,000; North Dakota, 608,000; and South Dakota, 453,000. Canvasback Increase the canvasback breeding population within the Waterfowl Breeding Bird Survey, Strata 41-49 from 50,000 to 104,000 breeding birds with the following distribution: Montana, 16,000; North Dakota, 69,000; and South Dakota, 19,000. Maintain an average age ratio of 1.3 immature females per adult female in the 5 fall flight. DEFINITION OF PROBLEM: Mallard The problem confronting the mallard in Region 6 is that the population is estimated to be approximately 230,000 breeding birds below the desired objective. This is a result of the basic fact that annual mortality exceeds the annual recruitment. Canvasback The basic problem confronting Region 6 i s that the canvasback breeding population is estimated to be 54,000 birds below the desired objective. The problem exists because the estimated annual recruitment rate of canvasbacks i s equal to or slightly less than the current estimated annual mortality rate. ANALYSIS OF CAUSES AND CONSEQUENCES: Mallard Since the turn of the century, breeding habitats of mallards have been encroached upon by man's agricultural practices which have gradually drained and cultivated the sloughs around which mallards nest. Draining sloughs and plowing new prairie lands continues today. The primary factor that has led to the decline of mallard population is low productivity. Low productivity is caused by three main factors: high annual hen mortality, low nesting success, and high ann immature mortality. Nearly all of these factors are ,n e with deficiencies in the mallards habitat. Male mallards have lower mortality rates than either immature or adult females. According to all surveys, drakes are present in excess to biological needs and are not considered in this problem analysis. However, drakes are not in excess for hunting. The annual survival rate of mallards is a complex issue. A recent study of mallard survival rates, based on an analysis of banding data, suggested a compensatory relationship between hunting and nonhunting mortality; nonhunting mortality may be more important than once thought. Available information concerning non-hunting mortality suggests part of this annual mortality is density independent. That is, the factors causing mallard losses are time specific and geographic in nature. The number of birds passing through or living in these hazardous areas will dictate the number of birds removed from the population. If birds are "saved" in one hazardous area and not at another, then more birds will die or be harvested at the other area simply because there were more birds available. Thus, to reduce annual mortality, those factors that are limiting the population must be managed collectively. There is sti l l much to be understood about this process and there is no guarantee of success. 6 This analysis is divided into three major components: adult hen mortality, low nesting success, and high immature mortality. 1. Adult Hen Mortality Disease: In Region 6, botulism is most severe during late surrmer and early fall. Certain weather conditions generally must exist before botulism die-offs occur. If detected early, this situation frequently can be managed to prevent high losses of mallards. In Region 6, Long Lake in North Dakota, Broadview Marsh in Montana, and the Great Salt Lake in Utah all have histories of botulism die-offs. Lead poisoning is generally a consistent killer of mallards each year because fresh lead is deposited each fall by waterfowl hunters. The annual loss has been estimated at approximately 4 to 5 percent of the mallard population. The Service has a program to phase out lead shot in heavily hunted areas, but the Service can implement the program only when the State wildlife agencies consent to the use of non-toxic steel shot. In Region 6, there are few areas where lead poisoning is a serious problem for mallards. Those identified are: South Dakota, along either side of the Missouri River from Pierre south to Pickstown; Nebraska, in Phelps, Kearney, Clay and Filmore Counties; Utah, in the marshes in Davis, Weber and Box Elder Counties around the Great Salt Lakes; and, in Kansas, five wildlife management areas. Except at Bear River Migratory Bird Refuge, no steel shot has been required on other waterfowl areas within the proposed zone in Utah,. Losses of ducks to lead poisoning are greatest in the winter following the hunting season and during the spring migration. Avian cholera has caused spring die-offs in the Rainwater Basin of Nebraska since 1975. This problem has been particularly severe in the western portion of the basin. Avian cholera is especially costly because the mortality occurs just prior to the breeding season when the populations are already low. Predators: Mallards arrive on the breeding grounds early in the spring when predators have few alternative foods. The red fox increased in the Dakotas in the 1940's and SO's and has become the major predator of mallards. Nesting hens are especially vulnerable to predation; 80 percent of the mallards taken by foxes are hens. It is estimated that fox predation can distort sex ratios from a hypothetical ratio of 1.0 drake per hen to a hypothetical 1.26 drakes per hen. However, data shows that mallards arriving at the breeding ground are already at 1.26:1. With breeding season mortalities of 8 percent for males and 30 percent for females, the sex ratio would be distorted to 1.66:1 by the end of the season. Predation on hens is especially harmful because the hen, the clutch she is incubating, and the potential for renesting all are lost. 7 Agricultural Practices: Land use in the pothole region is dominated by spring planted small grains and row crops which provide no wildlife habitat during the spring nesting and denning season. Therefore, certain mammalian predators and mallards are both concentrated into the remaining habitat. If the first nesting attempt fails, and the hens survive, they frequently renest in alfalfa fields, if available. Alfalfa must be cut just before the flowers bloom or protein is lost for cattle feed. Therefore, cutting occurs before most mallard nests hatch. During harvest, hens frequently stay too long on the nests and are killed by mowing machines. In North Dakota, alfalfa accounts for 5 percent of the habitat but 12 percent of the nests. No estimate of losses in alfalfa is available. Other agricultural practices, such as fall plowing and spring planting of crops, greatly restrict available nest sites for the mallard. Hunting: Analysis of banding data from the 60 1 s and early 70 1 s showed that hunting accounts for about 20 to 25 percent of the annual mortality. In hens, the average annual mortality is estimated at 46 percent; of this mortality, 40 percent is attributed to hunting. In recent years, 1974-81, mallard harvest has exceeded 40 percent of the estimated fall flight from the surveyed area. The recent figures were calculated using the Mallard Fall Flight Forecast and the estimated mallard harvest in the United States and Canada. In the Central Flyway, annual harvest of mallards correlates with the size of the fall flight, while in the Mississippi Flyway it correlates with the bag limit and season length. 2. Low Nesting Success The most hazardous periods in the life of the hen is the annual nesting season. To maintain a stable population, the fall flight of mallards should average at least 103 immatures per 100 adults. This requires that slightly more than 35 percent of the hens must reproduce successfully each year, and the broods should .fledge an average of at least five ducklings (based on annual survival rates as follows: adult male, 62%; adult female, 54%; immature male, 48%; and, immature female, 46%). A telemetry study suggested that only about 15.2 percent of the mallard hens produced broods. Low nest success is a crucial problem. To a large degree, the density of ponds per square mile limits the number of breeding mallards the region will have each spring. The number of ponds in the Dakotas and Montana is dependent upon the amount of rainfall received the previous year. Thus, mallards spread themselves across available wetland or, in dry years, move on to Canada. Even where potholes are maintained, farmers plow to the water's edge leaving no nesting cover. Grain fields such as wheat and oats support very few nesting mallards, yet these fields account for a very large percentage of the land area in the Missouri Coteau, Drift Prairie and Red River Valleys of Marth and South 8 Dakota. East of the Missouri River in North Dakota, croplands compose about 2/ 3 of the land area. East of the Missouri River in South Dakota, croplands make up more than 50 percent of the area. Each year about 1 to 2 percent of the remaining wetlands are drained and developed for agricultural use. Therefore, the annual variations in wetlands are superimposed over a general downward trend. Egg Success: Safe nest sites are necessary if mallards are to raise broods. However, in the eastern part of North Dakota, and to a lesser degree in South Dakota, former habitats suitable for nesting are under intensive agricultural uses. Suitable nesting habitat are like islands surrounded by intensively farmed areas. These islands provide attractive nesting habitat for mallards, but are also the homes of predators. The main egg eating predators are the red fox, skunk, raccoon, and Franklin's ground squirrel. This is an extremely serious problem because about 85 to 90 percent of the first nesting attempts are destroyed. Up to 92 percent of these losses of eggs are caused by predators. Mallard hens will renest if food and water are available. They show more and more stress with each successive attempt. This is reflectd in reduced body weights and smaller clutches. Both clutch size and success are lower for first year nesting hens than for older hens. Brood Success: While there is some degree of mortality of ducklings, it has not been studied to the same degree as nest destruction. Mink is a known predator of ducklings. When nest success is improved for hen mallards, higher duckling mortality may occur. Survival of ducklings to flight is forecasted as a new problem, once hatching success is greatly improved. 3. High Irrmature Mortality For this analysis, immatures are defined as birds aged from approximately 2 months to 18 months. Analysis of samples of banded immature mallards shows that only 46 and 48 percent of the immature females and males, respectively, will survive to the following fall. Hunting accounts for 45 percent of this group's annual mortality. Information shows non-hunting mortality is higher than hunting mortality in immatures. Mortality of immature mallards is highest during their first migration. There are reports that first-year breeding females are more susceptible to the nesting dangers previously mentioned for adult breeding hens. Information also suggests that the number of eggs laid is less and nest abandonment is greater. The percent of the problems that may be attributed to each cause has not been calculated. In Wildlife Resources, we are working on a computer model that will estimate the impacts of each cause, both individually and in groups. This model will also give insight into the likely consequences if each cause, or group of causes, is not resolved. 9 Canvasback Primary factors that we believe have led to low canvasback population levels are: r duced nestin success, destruction of breedin habitats, fre uent ~rou hts, i h hunting-caused mortality. Only 15 to 3 percent of~ earling canvasback hens return to e1r natal areas. Nearly all of the other 70 to 85 percent die during their first migration, indicating high vulnerability to hunting. These low return rates have occurred despite restrictive regulations on canvasback harvest. By 1900, breeding habitats of canvasbacks were being rapidly encroached upon by advancing human activities which were draining and cultivating the sloughs in which "cans" nest. Draining sloughs and plowing new prairie land still occurs. As land uses changed, predator co111Tiunities also changed. Large predators such as the coyote were eliminated from some areas and smaller predators such as the raccoon expanded its range into today overlaps the principal breeding range of the canvasback. Canvasbacks have specialized nesting and brood rearing requirements and are therefore sensitive to environmental changes, both temporary and long-term. Canvasback breeding habitat consists of wetland complexes and contains seasonal, semi-permanent and permanent marshes where water quality ranges from fresh to - moderately brackish. Annual habitat conditions play a major role in governing productivity. When habitat conditions become dry, canvasbacks' nesting effort is greatly reduced. Canvasback hens have extraordinary homing instincts so they return to their natal areas where, in dry years, they fail to nest. (Other species, in contrast, will move on north to Canada in search of suitable water.) When wetlands are filled to capacity, predation by raccoons can reduce nest success by 60 to 70 percent and nest parasitism by redheads can reduce productivity by 20 to 30 percent. Mink are known to kill hens on nests and ducklings but the extent of mink predation has not been documented. There appear to be suitable breeding areas remaining i n the Dakotas which are not utilized by canvasbacks. Densities are low in those areas which are used. Canvasbacks are very traditional in that they will return to the same area each year to nest and raise young. For this reason, canvasback hens are very poor pioneers. Thus, low numbers of canvasbacks in breeding areas are probably due primarily to low recruitment, not to emigration. Canvasback hens may shift to nearby areas if nests are repeatedly destroyed by predators or if intraspecific competition becomes severe. However, with today's low populations, intraspecific competition presumably is negligible. 10 Pairs seek secluded areas of a marsh or small wetland within the wetland complex to nest. Nests frequently are located in the upper end of the drainage system in small watersheds. The water quality is generally best at these sites. Emergent plants most often used for nest sites include flooded stands of cattails, bulrushes, whitetop, carex and willows. Successful adults reuse nest sites in subsequent years. Canvasback hens successful in hatching broods usually continue to repeat their nesting strategy. Females who have not developed patterns of success continue to develop new strategies. The experience factors dictate future success. Yearling hens return to natal areas and initiate nesting about one week later than adults. Clutch sizes are the same. While yearlings will renest if the first nest is destroyed,, they are not as productive as adults. The number of times a hen will renest depends on the availability of water at the nest site and the availability of high protein food. Historic information suggests that agricultural development limited canvasback breeding habitat and also encouraged the raccoon to invade the prairie pothole region. The raccoon is an important egg predator and may be a significant factor in the canvasback's apparent failure to increase in recent years. Interesting synergistic effects occur between water conditions, predation and nest parasitism. Canvasback nests are vulnerable to raccoons and mink in all water conditions. In dry years, when water recedes from beneath the nests, they become vulnerable to other egg eating predators such as red foxes and skunks. The renesting attempt by surviving hens coincides with the peak of egg laying by redheads, which parasitise canvasback nests. The number of redhead eggs in canvasback nests severely limits canvasback production. This problem is most severe in years of good habitat. Thus, canvasback productivity is limited in both wet and dry years. In early fall (September or early October), social characteristics and energy demands of hen canvasbacks and young make them very vulnerable to hunting. During this period, these birds are feeding to store energy for the migration. These small groups decoy easily, and are easy targets for hunters. In years of good production, young birds disperse widely among various habitats and frequently are shot by hunters not familiar with the canvasback. Adult birds use the more traditional marshes and, because of the varying degrees of protection given to these areas, survive at a higher rate. Recent studies suggest that 1.1 young females must be produced per adult hen per year to maintain a stable canvasback population; with more young hens the population increases, with fewer, it declines. 11 In the 1940-SO's, canvasback bag and season lengths were liberal. Hochbaum reported that during these decades canvasbacks were being overharvested in Manitoba. This left areas suitable for canvasback breeding, but vacant. The threshold harvest level for canvasbacks was likely exceeded. DESCRIPTION OF STRATEGY ELEMENTS: Habitat Development - FWS Land ~ strategic Element: Dense Nesting Cover (DNC) Species: Mallard Description: A mixture of grasses and legumes are planted on uplands within Wetland Production Areas (WPAs) that were formerly cropland. These plantings attract mallards and provide excellent nesting cover. Wetland district managers frequently contract planting of DNC with local farmers. Cause Abated: Reduces nest losses caused by agricultural practices and predation. Increases nesting densities. ~ Strategic Element: Island Construction Species: Mallard Description: Construction of islands within large bodies of water is limited to refuges where it is economically feasible. Islands are known to support large breeding populations of mallards. Construction of islands requires a 404 permit from the Corps of Engineers. Cause Abated: Predation on hens and eggs. Strategic Element: Native Grass Management (Refuge/WPA) Species: Mallard Description: Native grass provides nesting habitat. Currently is managed by either burning or by rotation grazing. Cause Abated: Native grasslands favor coyotes, which are less effective nest predators than foxes. Maintenance of permanent cover also reduces losses due to tillage. 12 Strategic Element: Fencing Waterfowl Production Area Boundaries Species: Mallard Description: Fencing reduces habitat loss or degradation by neighboring farming operations and illegal unauthorized vehicle use. Without fencing, a significant portion of DNC and native pra1r1e nesting sites are damaged by grazing trespass, cropland encroachment and vehicles. Cause Abated: Degradation of nest sites. Strategic Element: Methods Testing Species: Mallard and Canvasback The following are management practices that need further testing and acceptance before they can become operational. They are all intended for use in FWS lands. 1. Management for Second Nesting Attempt Description: Mallards are frequently attracted to alfalfa for second nesting attempts in regions where a large percentage of the land is planted to small grains or row crops. In WPAs with more than 150 acres of uplands, cooperating farmers will plant approximately 80-100 acres to alfalfa instead of DNC, when DNC is scheduled for planting or replanting. Harvest of alfalfa will be delayed until July 15. Recent studies show predators avoid alfalfa fields. This work requires that cooP,erators plant and harvest alfalfa by prescribed methods. Cooperators will receive the hay. 2. Silt Traps and Eros i on Control Description: Different methods will be tried to prevent filling of wetlands by either wind or water born silt. The silt traps should be managed as nesting sites. Various windbreaks should be tried to prevent buildups of "snirt11 (windblown snow plus dirt) in ponds. 3. Development of small breeding ponds on refuges where a constant water level can be maintained. 13 4. Reestablishment of sago pond weed in wetland complexes that have breeding canvasbacks. 5. Develop and test ways to improve success of the first nesting attempts by canvasbacks as a means of avoiding redhead parasitism which is common later in season when canvasback renesting occurs. Cause Abated: Predation of nests and loss of wetlands. Poor nutrition and redhead parasitism. Strategic Element: Public Awareness - Productivity Problems of Mallards Species: Mallard and Canvasback Description: We will develop TV, radio, magazine and newspaper releases explaining the decline in the mallard and canvasback population and problems of managing mallards for increased production. Develop factual information for presentations to conservation groups, etc. Cause Abated: Lack of public support to carry out certain management practices to increase the mallard population. Strategic Element: Mallard Management Model Species: Mallard Description: The computer model will be used to evaluate potential mallard management practices on WPAs and Refuges. Cause Abated: This will enable managers to make the best matches between all causes and the various management practices. Strategic Element: Evaluate Costs and Benefits of Various Management Options Species: Mallard Description: Analyses of discounted costs and benefits will be used to determine which management practices are the most economical in terms of ducklings produced. Cause Abated: This will enable managers to address all causes at the lowest cost. 14 Habitat Development-Off Service Lands Strategic Element: Native Prairie Management Species: Mallard Description: In Native Prairie, promote use of rotation grazing procedures that produce more grass, sustain more cattle, and produce more mallards. Appropriate grazing rotation on native prairie can provide nesting sites and improve production by reducing predation. Cause Abated: Agricultural practices that reduce nesting success. Strategic Element: Develop Stock Ponds: Species: Mallard Description: Promote the development of stock ponds west and south of the Missouri River in North and South Dakota and south of the Missouri River and in eastern Montana. FWS personnel would work with ranchers, and with both Federal and State Departments of Agriculture, to get more stock ponds built on private land - preferrably on intermittent streams with significant watersheds to fill ponds each spring under normal conditions. Cause Abated: Low breeding mallard populations where production is good and predation is low. Strategic Element: Develop New Farm Products Species: Mallard Description: This element requires research into potential new cash crops for farmers. Examples would be western wheat grass or green needle grass for seed. There is a market for these seeds where land has been disturbed in road construction, strip mining, etc. Both grasses are perennial which provide excellent nesting cover for mallards. Harvest of seeds occurs after eggs have hatched. This type of operation would be best encouraged in the drift prairie and Agassiz Lake Plain in eastern North Dakota. It would require developing contacts with farmers in target areas and cooperation of both Federal and State Agricultural Departments. 15 Cause Abated: Attract ducks to good nesting sites and reduce nest losses caused by agricultural practices. Strategic Element: No-Till Winter Wheat Species: Mallard Description: This practice would be accomplished through the U.S. Department of Agriculture (USDA) and State Departments of Agriculture and encouraged on private lands primarily in eastern North Dakota where winter kill is less likely. Stubble would be left 12 inches high, and winter wheat would be seeded into the stubble in the fall. If 25 percent of the spring wheat farmers converted to no-till winter wheat, it would provide safe nesting sites for a significant portion of the nesting mallards (statistics are unknown at this time). Winter wheat could be encouraged through demonstration areas on refuges, provision of free seed, and provision of no-till planters. Cause Abated: This would create nesting habitat free of spring tillage and greatly reduce nest destruction now caused by tillage. Dispersal of nests may reduce predation. Strategic Element: Other Agricultural Practices that are Compatible with Wildlife Species: Mallard Description: We would search out energy efficient agricultural practices that would be mutually beneficial to wildl i fe and to the landowner. FWS personnel would work with both Federal and State Agri culture Departments, State universities, State game and fish agencies, and landowners to develop new practices. Cause Abated: Hen losses due to agricultural practices and nest/clutch destruction to agricultural practices. Strategic Element : Potential Economic Value of Mallards Species: Mallard 16 Description: Landowners could receive substantial economic benefits from waterfowl hunters, if hunting on WPAs were more tightly controlled. Landowners could lease, rent or charge daily rates for hunting. This would provide landowners with an incentive to save wetlands. Cause Abated: Reduce high hunting mortality of hens and immatures during early part of season. Strategic Element: Economic Incentives for Better Soil Conservation Practices Species: Mallard and Canvasback Description: Federal tax laws, credit programs and agricultural programs could be modified to provide greater incentives for soil conservation. Cause Abated: Wetland degradation and overall general habitat losses. Management of Predation Strategic Element: Mammalian Species Composition Species: Mallard and Canvasback Description: Lands would be managed to reduce red fox, raccoon, skunk, and Franklin ground squirrel populations where the coyote is the dominate predator. The fox~ raccoon, skunk and ground squirrel are very effective nest predators, while the coyote and badger are a lesser problem to breeding mallards. Cause Abated: Reduce nest predation. Strategic Element: Management of Predation on WPAs Species: Mallard and Canvasback Description: Use management techniques that will reduce red fox, raccoon, skunk, and Franklin ground squirrel predation on WPAs in the spring. Cause Abated: Loss of eggs and hens. 17 Strategic Element: Habitat Manipulation to Reduce Franklin Ground Squirrel Populations Species: Mallard Description: Habitat would be managed to discourage Franklin ground squirrels from using WPAs. The litter and duff on the ground should be reduced by controlled burning, shorter rotation on rejuvenating DNC or different crops. Help will be requested from research or universities to determine the best practices. Cause Abated: Loss of eggs. Strategic Element: Coyote Conflicts Species: Mallard Description: Prevent red fox from becoming the dominant predator in areas where coyotes conflict with livestock growers and coyote control is necessary on FWS land. Red fox populations will be managed by ADC within the same area. This will require cooperation of State Game and Fish Agencies. Cooperative Agreements should be developed for this situation. Cause Abated: Predation on mallard hens and nest/clutch destruction. Strategic Element: Develop Predator Trapping Program Species: Mallard and Canvasback Description: FWS should encourage State wildlife agencies to emphasize the harvest of red fox, raccoons and skunk. Cause Abated: Reduce predation of hen mallards and nests. Strategic Element: Methods Testing Species: Mallard Description: The following are management options that need further testing and acceptance before they can become operational. Methods are for use on FWS lands in specific geographic areas. 18 1. Predator Exclusion - Electric Fences: Electric fences can be used to exclude mammalian predators from WPAs in areas of intensive farming and high predation. This may work only for the larger mammalian predators such as red foxes, raccoons, and skunks. 2. Safe Nest Sites - Rock Islands: Islands made of rock provide safe nesting sites for mallards on easements that have semi-permanent ponds of a size sufficient to have islands. The techniques would be limited to areas where land clearing has resulted in large rock piles in and around fields. During the winter, the landowner would be allowed to remove rock piles from farmland to the centers of semi-permanent or temporary ponds under easement. The technique is i llegal at this time because it violates easement contracts. 3. Safe Nest Sites - Nest Baskets: Nest baskets would be tested in areas where large proportions of the land area are intensively farmed for small grain or row crops. FWS and State wildlife agencies would encourage local 4-H, FFA, Boy Scouts, conservation organizations, etc., to put up nest structures provided by FWS. 4. Red Fox - Management on River Refuges: This element would reduce hen and nest predation on refuges located along rivers. Red foxes would be removed before the female foxes have young on or near the refuge. This would greatly reduce the number of early nesting mallards taken to feed the pups. State Game and Fish cooperation and publ i c acceptance of program would be required. Cause Abated: 1. Loss of hens and eggs. 2. Reduce nest destruction by agricultural practices and predation. 3. Reduce egg and hen predation by red foxes on certain river refuges. 19 Increase High Protein Food (FWS Refuges Only) Strategic Element: Inventory and Classify FWS Water Impoundments, Lakes, and Permanent Ponds Species: Mallard and Canvasback Description: Conduct an inventory to determine the physical and chemical properties of water, whether lake or pond is fed by ground re-charge or run-off water, and management capabilities of impoundments and lakes. This will identify bodies of water FWS can manage for improved quality and food for nesting mallards. Cause Abated: Lack of resource information. Strategic Element: Production of High Protein Foods for Breeding Mallards Species: Mallard and Canvasback Description: 1. By improving water management in refuge impoundments, more invertebrates can be produced. High protein foods are needed by mallard and canvasback hens and ducklings during the reproductive cycle. Removal of rough fish can reduce the turbidity of water and increase emergent plants and invertebrates populations. It is important to have high quality foods during dry years when refuges support the highest numbers of breeding waterfowl. 2. Properly regulated impoundments can stimulate emergent plant growth and increase invertebrate populations. Obnoxious plants can also be controlled if sufficient water is available to reflood the impoundment. Without enough water, problems with disease or unwanted plant invasion can occur. Cause Abated: Poor hen nutrition. Habitat Preservation Strategic Element: Wetland Complexes - Canvasback Species: Canvasback 20 Description: To identify Wetland Complexes that have canvasback management potential. The Complex characteristics are as follows: 1. At least 85-100 basins per square mile comprised of seasonal, semi-permanent, permanent ponds ranging in size from approximately 0.2 acres in seasonal ponds to several acres in permanent ponds. The 85-100 basins per square mile should be present during the spring when wetland conditions are at the seasonal peak. 2. Examine for sago pond weed. Should have had history of sago in recent 10-15 years. 3. Must have breeding canvasbacks. 4. Minimum size of fee land is 1/2 section for management. 5. Over water nesting habitat sites available. Cause Abated: Reduced nest sites, and agricultural practices, and, to some degree, predation. Strategic Element: Wetland Complexes - Mallard Species: Mallard Description: Identify existing areas of greatest potential to increase mallard populations and define how much additional lands in fee and easement would be needed to secure these areas1 as management units. Identifying the basic components of individual wetland complex needed for intensive management is extremely important if FWS is to offset current losses of mallard breeding habitat. Cause Abated : Wetland Drainage Strategic Element: Purchase and Easement Program Species: Mallard and Canvasback Description: 1. This element is designed to attract more mallards by protecting existing wetlands by easement and by purchasing and plugging drai ned wetlands. 21 2. Easements would be taken to prevent drainage of potential canvasback habitat. First priority should be easements that complete wetland complexes that have breeding canvasbacks. The second priority would be areas that have potential for canvasback breeding. Cause Abated: Wetland drainage; attract more mallards. Strategic Element: Law Enforcement/Easement Program Species: Mallard and Canvasback Description: Easements will be checked annually for deliberate drainage violations. Drained wetlands will be restored. Cause Abated: Wetland drainage. Strategic Element: Environmental Protection Species: Mallard and Canvasback Description: FWS will screen and comment on proposed wetland alteration by other Federal agencies or by the private sector under Federal permits. Cause Abated: Wetland degradation and drainage. Strategic Element: Wetlands Inventory Species: Mallard and Canvasback Description: Early completion of the wetlands inventory for eastern Montana, North Dakota and South Dakota is essential. This information is needed to develop management strategies. Cause Abated: Baseline information is needed to develop certain management practices. It will provide a measure of wetland drainage. Strategic Element: Legislation to Protect Habitat Species: Mallard and Canvasback 22 • Description: 1. The current Wetland Loan Act should be extended for at least 10 years before payback begins. 2. The States could defer proper taxes for landowners who maintain wetlands. The deferred taxes would become due only when the wetlands are drained. This is not a function of FWS, but should be encouraged. 3. As an alternative, the States could reduce property taxes for landowners who maintain wetlands. Cause Abated:· Wetland Drainage. Population Surveys Strategic Element: Waterfowl Breeding Bird Surveys Species: Mallard and Canvasback Descripti on: Conduct annual Waterfowl Breeding Bird Surveys for use in evaluating mallard breeding population trends. Cause Abated: None, but the surveys will be used to evaluate overall effectiveness of management. Strategic Element: Waterfowl Brood Surveys Species: Mallard and Canvasback Description: Conduct the annual Waterfowl Brood Count Survey for use in estimating fall flight of mallards. Cause Abated: None, but these surveys are used to evaluate overall effectiveness of management. Strategic Element: Hunting Activity Surveys Species: Mallard and Canvasback Descri ption: Hunters are surveyed by mail to estimate annual kill of ducks. Cause Abated: Surveys are used to evaluate hunting mortal ity. 23 Strategic Element: Parts Collection Survey Species: Mallard and Canvasback Description: Duck wings are collected and identified to estimate species composition of annual waterfowl harvest. The survey provides the proportion of the mallard harvest by State. Cause Abated: The survey provides data on annual mortality of mallards by age and sex and State. Research and Development Strategic Element: Identify Factors Impacting Brood Survival Species: Mallard Description: Research is needed to identify problem in brood survival. Little information is available because too few nests have hatched in recent years. Cause Abated: Brood mortality. Strategic Element: Develop Management Practices to Reduce Brood Losses Species: Mallard Description: Potential management practices that could improve brood survival from hatch to fledgling will be investigated. Cause Abated: Brood mortality. Strat~gic Element: Evaluation of Banding Species: Mallard Description: Recent findings suggest data from banded samples of mallards may not be representative of the population. Banding may not detect actual change in the mallard population because variation in annual survival may be less than can be measured by the technique. That is, differences between natality and mortality may be less than can be detected with banded samples. Cause Abated: None. This has potential to change hunting regulations that may impact annual survival. Strategic Element: Develop Survey Methods that can Detect a Three Percent 24 Change in Annual Survival Rates Species: Mallard Description: The balance in nature between natality and mortality is extremely sensitive and changes are likely very small over time. A population will decline when slightly more birds die than are raised. These changes are subtle and difficult to detect. Current sampling techniques are not sensitive enough to detect these small changes. Therefore, new techniques are needed to detect small annual changes between natality and mortality. Cause Abated: None, but this could lead to changes in hunting regulations. Strategic Element: Disease Research Species:: Mallard Description: No new disease research has been defined at this time. Cause Abated: Mallard losses to disease. Strategic Element: Late Maturing Alfalfa Species: Mallard Description: Late maturing varieties of alfalfa would be identified and evaluated for use on WPAs. Late maturing alfalfa could give better nest sites and better alfalfa crops for the cooperating farmers. The alfalfa would be used where predation is a serious problem. Cause Abated: Poor nest sites and reduced predation. Disease Management Strategic Element: Rainwater Basin, Nebraska Species: Mallard Description: Control of mallard die-offs during spring staging in the Rainwater Basin in South Central Nebraska is a joint program with the Nebraska Game and Parks Commission. Preventive measures are taken to keep birds away from areas known to 25 harbor avian cholera. Sanitation measures are taken where appropriate. Basin management should be to reduce nutrient runoff through reduced applications of fertilizers, split applications, timing of applications, and through organic farming and minimum tillage. Cause Abated: Annual mortality of immature and hen mallards. Strategic Element: Disease Contingency Plans Species: Mallard Description: Disease contingency plans should be reviewed and updated at refuges where disease problems exist. Cause Abated : Losses of mallards to disease. Strategic Element: Non-toxic Shot Program Species: Mallard and Canvasback Description: The Service should determine whether a better way can be developed to implement the non-toxic shot program. Cause Abated: Mallard losses to lead poisoning. FWS Administration Strategic Element: Develop New Fish and Wildlife Service and State Harvest Policies Species: Mallard and Canvasback Description: Determine whether or not current hunting regulations can be better designed to effectively reduce harvest of hens when needed. Cause Abated: Reduce annual mortality of mallards. Strategic Element: Management Training Spec i es: Mallard and Canvasback 26 Description: FWS should provide training at appropriate levels of management for effective and efficient use of money, man-power, and capi tol investments to achieve mallard objectives. Cause Abated: None, but is designed to increase our efficiency in meeting objectives. Strategic Element: Administer and Enforce All Migratory Bird Regulations. Species: Mallard and Canvasback Description: An aggressive law enforcement effort insure that mallards are protected under existing laws and regulations. Cause Abated: Annual mortality of mallards. PRELIMINARY SCREENING: At this time, it i s not feasible to screen strategy elements. Screening could be logically done after the following series of steps. 1. The existing list of potential strategy elements should be reviewed for additions, deletions, and modifications by Northern Prairie Wildlife Research Center, Project Leaders and Wetland District Managers within Montana, North Dakota, South Dakota, and Nebraska. 2. State fish and game agencies in the Prairie Pothole Region should have the opportunity to add to, delete or modify these el ements. This is especially important since many strategy elements require their approval. A visit to each State to discuss elements should be made since State game and fish agencies would have the fi nal say on several strategy elements impacting their program. 3. The Central Flyway technical and council member States should review the strategies. The final draft should be sent to member States for review through the Central Flyway Representative for di scussion at the Central Flyway Technical Meeting in March. If appropriate, the Central Flyway Council could endorse or reject all or part of the plan at their meeting at the North American Wildlife Conference in Wichita, Kansas in March and April. 4. We shou l d use the Mallard Management Model to evaluate combinations of strategy elements. This would be done in cooperati on with FWS Area Supervisors and Project Leaders. 27 CHARACTERISTICS OF AFFECTED PUBLICS: Mallard A large public, composed of waterfowl hunters, express their desire to have more mallards for hunting through State game agencies and Flyway Councils. The hunting publics of Canada represented by the Canadian Wildlife Service and the Fish and Wildlife agencies of the Prairie Provinces are impacted by the management schemes for mallards carried out by the United States. The agricultural public is impacted by a high population of mallards, especially in the fall when crop depredations occur. Fish and Wildlife programs that remove land from the tax rolls have created dissatisfaction among local county governments in areas of North Dakota, South Dakota and Montana. Money is paid in lieu of taxes, but County and State officials are concerned about reduced tax revenue. The Central Flyway Council believes this is one of the major reasons States are opposing land acquisition through the small wetlands program. The State Fish and Wildlife Agencies try to satisfy the demands of the hunting public. These agencies respond to factors impacting hunting in their States individually and collectively through the Flyway Councils. These State agencies are impacted by our management programs. Proponents of the Garrison Diversion Unit in North Dakota have been frustrated by the requirements for mitigation of the impacts on mallards and other wildlife. Farmers who favor drainage to add to land acreage for crop production can be impacted by the Service 1 s policy to discourage drainage of wetlands in North Dakota, South Dakota and Montana. The agricultural public is not impacted by the low population of canvasbacks, but it is affected by efforts to preserve breeding habitat. · Ultimately, the actions of this group may determine the size of canvasback populations. SOURCES OF INFORMATION: Anderson, D.R., 1975. Population ecology of the mallard V. Temporal and geographic estimation of survival, recovery and harvest rates. U.S. Fish and Wildl. Serv. Res. Publ. 125. llOpp. Anderson, D.R., and K.P. Burnham, 1976. Population ecology of the mallard, VI. The effect of exploitation on survival. U.S. Fish and Wildlife Service Resource Publication 128. 66pp. 28 • Hochbaum, H.A., 1959. The canvasback on a prairie marsh. Stackpole Co., Harrisburg, PA. 207 pp. Hochbaum, H.A., 1947. The effect of concentrated hunting pressure on waterfowl breeding stock. Trans. N.A. Wildl. Conf. 12: 53-56. Johnson, D.H., and A.B. Sargeant, 1977. Impact of red fox predation on the sex ratio of prairie mallards. U.S. Fish and Wildl. Serv. Res. Rept. No. 6. 30pp. Lokemoen, J.T., H.A. Doty, D.E. Sharp, and J.E. Neaville. Electric fences to reduce mannnalian predation on waterfowl nests. NPWRC. (Manuscript in prep.). Miller, Harvey. Central Flyway Representative. Personal connnunications. Martin, E.M., and S.M. Carn, 1977. Population ecology of the mallard IV. - A review of duck hunting regulations activity, and success, with special reference to mallards. U.S. Fish and Wildl. Serv. Res. Publ. 130. pp137. Martz, G.F., 1967. Effects of nesting cover removal on breeding puddle ducks. J. Wildl. Manage. 31(2):236-247. Nichols, J.D., and G.M. Haramis, 1980. Inferences regarding survival and recovery rates of winter-banded cnvasbacks. J. Wildl. Manage. 44: 164-174. Olson, 0.0., 1964. Differential vulnerability of male and female canvasbacks to hunting. North Am. Wildl. Nat. Resour. Conf. 30: 121-135. Pospahala, R.S., D.R. Anderson, and C.J. Henny, 1974. Population ecology of the mallard II. Breeding habitat conditions, size of the breding population, and production indices. U.S. Fish and Wildl. Serv. Res. Publ. 115. pp73. Sargeant, A.B., and R. J. Greenwood. Striped skunk spatial distribution, habitat use and food utilization in a prairie-marsh environment. Unpublished data, NPWRC, Work Unit 901.06. Sargeant, A.B., 1972. Red fox spatial characteristics in relation to waterfowl predation. J. Wildl. Manage. 36(2):225-236. Sargeant, A.B., 1978. Red fox prey demands and implications to prairie duck production. J. Wildl. Manage. 42(3):520-527. Sargeant, A.B., S.H. Allen, and R.T. Eberhardt. In prep. Red fox predation on breeding ducks in midcontinent North America. Sargeant, A.B., G.A. Swanson, and H.A. Doty, 1973. Selective predation by mink, mustela vi son. on waterfowl. Am. Midl. Nat. 89(1):208-214. 30 .... Bellrose, F.C., 1978. Ducks, geese and swans of North America. Stackpole Books, Harrisburg, PA. 540 pp. Bent, A.C., 1962. Life histories of North American wild fowl, Part One. Dover Publications, Inc. 244 pp. Cowardin, L.M. Estimation of mallard recruitment in the midcontinent waterfowl management unit. Unpublished data, NPWRC, Work Unit 901.13 Drewien, R.C., and L.F. Fredrickson, 1970. High density mallard nesting on a South Dakota island. Wilson Bull. 82(1):95-96. Duebbert, H.F., et al. Duck nesting studies related to land use in eastern North and South Dakota. Unpublished data, NPWRC, Project 421. (inactive). Duebbert, H.F., et al. Duck nesting of Waterfowl Production Areas in North Dakota, 1969-74. Unpublished data, MPWRC, Project 421. (inactive). Duebbert, H.F., and H.A. Kantrud, 19 74. Upland duck nesting related to land use and predator reduction. J. Wildl. Manage. 38(2):257-265. Duebbert, H.F., and J.T. Lokemoen, 1980. High duck nesting success in a predator reduced environment. J. Wildl. Manage. 44(2):428-437. Duebbert, H.F., and J.T. Lokemoen. Island nesting of ducks at Miller Lake, North Dakota. Unpublished data, NPWRC, Work Unit 905.06. Duebbert, H.F., and J.T. Lokemoen, 1976. Duck nesting in fields of undisturbed grass-legume cover. J. Wildl. Manage 40(1):39-49. Doty, H.A., F.B. Lee, and A.O. Kruse, 1975. Use of elevated nest baskets by ducks. Wildl. Soc. Bull. 3(2):68-73. Eberhardt, L.E., and A.B. Sargeant, 1977. Mink predation on prairie marshes during the waterfowl breeding season. Pages 33-43 in R.L. Phil l ips and C.Jonkel, eds. Proceedings of the 1975 Predator Symposium. Montana Forest and Conservation Experiment Station, Missoula, Montana. Greenwood, R.J. Effect of mammalian predator reduction on success of waterfowl nests. Unpublished data, NPWRC, Work Unit 911.01. Heismeyer, G.L., 1974. Evaluation of duck production on Waterfowl Production Areas in northeast North Dakota. M.S. thesis, South Dakota State University, Brookings. 44pp. Higgins, K.F., 1977. Duck nesting in intensively farmed areas of North Dakota. J. Wildl. Manage. 41(2):232-242. 29 ... 0 Schranck, B.W., 1966. Waterfowl nest sites and predation. M.A. thesis, University of Missouri. 104pp. Serie, Jerry (May, 1982) Personnel communications via telecom. Stewart, R.E., A.O. Geis, and C.D. Evans, 1958. Distribution of populations and hunting kill of the canvasback. J. Wildl. Manage. 22: 333-370. Talent, L.G., R.L. Jarvis, and G.L. Krapu. Submitted for publication. U.S. Fish and Wildlife Service, 1982. A National Waterfowl Management Plan for the United States FWS. 32pp. USFWS - Data from Waterfowl Breeding Bird Survey. Computer printout by year, species, and strata between 1955 and 1981. USFWS - Data from Waterfowl Brood Count Surveys. Data available by year, and strata and brood size. 31 .. • DETERMINING FACTORS BIRD CONDITION} NO WATER CONDITIONS --- DAY OF SEASON YES COVER DENSITY} SELECT NEST COVER ABUNDANCE --- HABITAT L.------,..------' EGGS LAID1 _ _ _ REDUCE CONDITION DAYS INCUBATEDj OF BIRD PREDATION RATE IN ] SELECTED COVER ____ _ NO AGRICULTURAL PRACTICE ON-NEST SURVIVAL RATEJ------YE~------Y_E_S-< BIRD CONDITION} NUMBER DAY OF INITIATION --- HATCHED '------,..------' NO BROOD SURVIVAL RATE}---- YES OFF-NEST MORTALITY RATE}------y NUMBER FLEDGED NUMBER NUMBER FEMALES FEMALES ALIVE DEAD -...... -.-."'. -... -...... -.-. - ..- . .-...... - .- .- . -. -. -.. .-.... - ...... - . .- . .- ...... · ...... t-• ••••••••••••••• ••••••••••••• • • ••••••••••••••••••••• ••••••••••••••••••• • ••••••• •••••••••••••••• • • • • • • • • • • • • • • .. ,I ...... ! ; ·' ...... ,,- ...... • • . • • • • • • • • . • • .• .• • .# .. • . •••••••••••••••••••••••••••••••...... COLLECT :•:•:•:• SIMULATED PRODUCTION -:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:•:•:-:-:• INITIAL DATA ...... •:•:-:-:...... UNDER...... MANAGEMENT ...... :. .•: ...... • .:-:•:•: . . .• .:-: .• .:-: .-:-:-:...... :•: ...... •:•:• . . .:-: . • .:-: ...... WATERFOWL ...... COMPLETED • • • •. • PROPOSED • •.•. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •. • HABITAT '"""'...... ,..,. .... 'l • • • • • •••••• •• ••••••••••••••••••••• • WATERFOWL DATA BASE ...... STUDIES ...... (500 PLOTS) ...... ,,..,~'io-...... ~ ..... -r •.-, ...... : •:·=.:.:.:.:.: ·=· :•:.:.: •:.:.:.:.:.: ·~--·.:-·--·~· : :::::::: . . ::::: . . .:: : .: :. : :. : :. :=: . .:::: . .::: . ::: . .:: :.: :. ::::: . . . ::: . NPWRC NEST DATA BASE ...... ::: :: : : : : : : : :: :::::::: ::: : : ; : : PAIR - WETLAND :: :: : : : : : : : ::::::::::::::::::: REGRESSION MODEL : .: : .: : .: : .: : :.. : .: : : .: : ..: : : : :. : .: : ...: : : : : : :. : .....: : : : : : : : : : .: : ...: : : : .: : : .=·:.: =.= : =. : =.: .:= =.: ..=:: . :.=: :_·: =.: =.: .=: =. 111111 1 1 1 ---~~~~~---;_,;,..:-=;-:;"":=.., :,..=..,.: -: :T'= :: t = :;:1111 ilil llllllillli lilllllllllll lililll ill llllillil!!!!!l!ll l: :-:·:• :•: ·: ·: •:•:. . .·: .·: .·: .·: .·: .·: .·: .·: .·: .·: .·:• .: .•:~es: ...... ·:·: ·:·:·:·:•:·:•:•:-:•:.·: .· . -...... ' ...... ~..... --,...... · WATERFOWL PRODUCTION ...... : RESEARCH1·· •.• • •.•.•. • • • · · :•:•:•:• : •:•:•:•:•. NEST SIMULATION success RATES • STUDIES .• ••. . . .•. . N .. o. . .•. . .•. . . • ...... • • •. •. •. •. •.•.•. • • •. ·•. MODEL ...... ·...... ".~ . ..~ ..~. . -·""""'- ...... ·""· ...... 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STATISTICS MANAGER • • • • • • • • • NO • • • • • • • • • • • • • • • • • • • • • • • .• • • • • • • • • TYPE AND • • • •. •. •. •. , • MEET11 ,,OBJECes/.·.·.·.· • • . • .•·.·.• • ·.• . ·.·• . • . ·.·.·•.• .•. ·•..·. • . ·.·.• . •. •.·.· • .• ·• ..•·.·.·.• • .•.· •..·.·.• • • • ·• LOCATION ADMINISTRATORS ...... ' ,_ ~ ...... - -- ...... _____··········.__ . . _. _...... ·· . .·· . .· .··-· . . -...... ==: = = = ==:: ======:=EB-:_ =: ======:: ======: ======: ==: = ...... :... =:: .....== == ...... =: . - -vy.- ...... ~.-:... =: =:.... == .. =..:= .... =: = = ...... = =: =: =: .: ·' ...... - --...... ' SIMULATED - ' ...... -...... · . CURRENT •:': •: •: •:•: •:• :•: •:• :•: •: •:•: • : • S"J OP :-:-:•:-:• :-:-:-:•:•:•:•:•:• : •: • :-:-:-:•:-:-:•:-:-: •: ' ...... ' PRODUCTION ...... -- ...... 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