Minnesota Cooperative Fish & Wildlife Research Unit

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    Biennial Report, January 1995 - December 1996
    (1997) Minnesota Cooperative Fish and Wildlife Research Unit
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    Biennial Report, January 1997 - December 1998
    (1999) Minnesota Cooperative Fish and Wildlife Research Unit
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    Biennial Report, January 1999 - December 2000
    (2001) Minnesota Cooperative Fish and Wildlife Research Unit
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    HOME RANGE AND HABITAT USE OF NORTHERN GOSHAWKS (Accipiter gentilis) IN MINNESOTA
    (2001-04) Boal, Clint W; Andersen, David E; Kennedy, Patricia L
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    POPULATION TRENDS OF TUNDRA-NESTING BIRDS IN CHURCHILL, MANITOBA: POTENTIAL EFFECTS OF INCREASING LESSER SNOW GOOSE (CHEN CAERULESCENS CAERULESCENS) POPULATIONS
    (2001-08) Sammler, John E
    Recent increases in lesser snow goose (Chen caerulescens caerulescens) abundance have raised the question of how populations of other tundra-nesting birds are impacted by increased goose herbivory and habitat degradation. Line transect surveys were conducted on 30 transects at the Nestor 1 study site outside of Churchill, Manitoba in June 1984, 1999, and 2000 to obtain estimates of population densities of tundranesting birds and determine if density changes have occurred in relation to increased goose habitat damage. We also compared bird abundance at a smaller scale between degraded and non-degraded freshwater sedge meadows. Herring gulls (Larus argentatus) and semipalmated sandpipers (Calidris pusilla) exhibited significant (P < 0.05) increases in population densities from 1984 to 1999 and 2000. Dunlins (Calidris alpina) had significantly lower densities from 1984 to 1999 (P < 0.10) and nonsignificant declines from 1984 to 2000. Horned larks (Eremophila alpestris), lapland longspurs (Calcarius lapponicus), savannah sparrows (Passerculus sandwichensis), and the sedge meadow shorebird guild exhibited nonsignificant increases in density. The tundra-nesting passerine guild exhibited a significant (P < 0.05) increase in density from 1984 to 1999. Arctic terns (Sterna paradiseaea), pectoral sandpipers (Calidris melantos), and willow ptarmigan (Lagopus lagopus) indicated significant (P < 0.05) declines in densities of birds seen on transects and in the numbers of transects birds were detected on. Significantly lower abundances of passerines and shorebird guild birds were detected in degraded freshwater sedge meadows versus non-degraded meadows. Results indicate that most species did not exhibit population density declines over time on the study area, despite increased snow goose damage and density. However, at the scale of the habitat patch, the same groups of species had lower abundances in degraded habitats versus non-degraded habitats. Results suggest that habitat degradation led to lower bird abundance, however habitat damage may have to be widespread and severe to elicit population density declines over a large area, like Nestor 1. The species that exhibited density declines over the study area were larger, ground-nesting species.
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    Evaluating and Developing Survey Techniques Using Broadcast Conspecific Calls for Northern Goshawks in Minnesota
    (2001-09) Roberson, Aimee, M.
    Broadcast surveys are effective at detecting northern goshawks (Accipiter gentilis) during their breeding season. Goshawk surveys are generally conducted using the alarm call during the nestling phase and the juvenile food-begging call during the fledgling-dependency phase (referred to as “standard calls”). However, goshawks are more vocal during their courtship phase than at any other time of the year. Because the probability of detecting goshawks declines after a nest has failed, a reliable means of surveying goshawks during the courtship phase would be more likely to detect nesting pairs than surveys conducted later in the breeding season. To evaluate the influence of breeding phase, distance, and call type on the probability of detecting goshawks, I estimated goshawk detection rates during the courtship, nestling, and fledgling-dependency stages of the breeding season, using three conspecific calls (adult alarm call, male contact call, and juvenile food-begging call) at distances of 100, 150, 225, and 325 m from active nests in northern Minnesota. Unlike previous studies, broadcasts were conducted at only one distance per trial to better describe the relationship between distance and probability of detection and to estimate effective area surveyed per broadcast station. In 1999, 85 broadcast trials were conducted in 9 active nest areas. Detections occurred during 18.9% of broadcast trials and during at least one broadcast trial at 9 of 11 nests. In 2000, 132 broadcast trials were conducted in 16 active nest areas. Detections occurred during 48.5% of broadcast trials and during at least one broadcast trial at all 16 nests. When using standard calls during broadcast trials and when pooled over all distances, detection rates were highest during the courtship (70.4%) and fledgling-dependency phases (67.6%). Detection rates were lowest during the nestling phase (28.1%), when there appeared to be higher variation in the likelihood of response among individuals. During the courtship and fledgling-dependency phases, detection rates decreased with distance from goshawk nests, whereas during the nestling phase, detection rates were highest at 225 m from nests. Differences in detection rates among breeding phases highlight the importance of incorporating knowledge about local breeding phenology into survey design. The male contact call did not improve detection rates over the alarm and juvenile food-begging calls. Results from this study will assist iv in designing systematic landscape-level surveys with a known probability of detection in the Western Great Lakes Region (WGLR) and in defining a distance-detection relationship for calibrating results of extensive surveys. I used probability of detection as a function of distance in the courtship and fledgling-dependency phases to calculate the effective area surveyed per broadcast station using the survey techniques recommended in this paper. The effective area surveyed was 39.8 ha during the courtship phase and 34.4 ha during the fledgling-dependency phase. These results indicate that in Minnesota broadcast stations may be spaced 712 m and 662 m, respectively, when conducting systematic surveys during these two breeding phases. Calculation of the effective area surveyed could be applied to other regions where the probability of detection as a function of distance is known.
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    PRODUCTION OF EPP CANADA GEESE NEAR CAPE CHURCHILL IN 2002
    (2002) Andersen, David E. et al
    Nest searching for Eastern Prairie Population Canada geese was conducted on the Nestor One Study Area near Cape Churchill, Manitoba from 9-19 June 2002. A total of 42 nests was found in initial searches of 732 ha of wetlands in 14 primary sample areas, 55 nests were located in searches of 6 coastal sample areas, and 38 nests were located in 5 additional sample units north, south, and east of the primary units. Five additional nests were located subsequent to initial nest searching, resulting in a total of 140 nests. Nest density (unadjusted for observability) in the primary sample areas was 5.74 nests per 100 ha of wetland—comparable to nest density recorded on the Nestor One study area in the mid-1990s, but 29% lower than the nest density observed in 2001. Clutch size in 136 nests with eggs present when located averaged 3.63; lower than the long-term mean of 3.91 (1976-2002), but near the clutch size expected based on the established relationship between mean clutch size and median hatch date. Estimated median hatch date was 4 July, and ranged from 29 June to 10 July—the second latest estimated median hatch date in the period 1976 through 2002. Nesting success calculated as the average apparent success rate of nests active when first located during initial nest searching (0.36) and the 28-day survival of nests based on exposure days (0.78) was 0.57—similar to the average nesting success of 0.63 observed during the 1990s. Based on these estimates of nest density, clutch size, and nesting success, gosling production at Nestor One was approximately 11.9 per 100 ha of wetland—near the average of 16.5 goslings per 100 ha of wetlands observed in the 1990s. Thus, production at Nestor One in 2002 was near average levels observed in the 1990s, in spite of late phenology that resulted in late nesting by Canada geese on the study area.
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    The 2002 Waterfowl Hunting Season in Minnesota: A Study of Hunters’ Opinions and Activities
    (2002) Schroeder, Sue; Fulton, David C; Lawrence, Jeffery S
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    PRODUCTION OF EPP CANADA GEESE NEAR CAPE CHURCHILL IN 2003
    (2003) Andersen, David E. et al
    Nest searching for Eastern Prairie Population Canada geese was conducted on the Nestor One Study Area near Cape Churchill, Manitoba from 4-11 June 2003. A total of 57 nests was found in initial searches of 732 ha of wetlands in 14 primary sample areas, 57 nests were located in searches of 6 coastal sample areas, and 44 nests were located in 3 additional sample units south and east of the primary units. Two nests were located subsequent to initial surveys or outside of surveyed sample areas, for a total of 160 nests located on the Nestor One study area in 2003. Nest density (unadjusted for observability) in the primary sample areas was 7.79 nests per 100 ha of wetland— near the highest nest density recorded on the Nestor One study site since the late 1980s, and 36% higher than that estimated in 2002. Clutch size in 143 nests with eggs present when located averaged 4.51—higher than the long-term mean of 3.93 (1976-2003) and the clutch size expected based on the established relationship between mean clutch size and median hatch date. Estimated median hatch date was 25 June, and ranged from 17 June to 1 July, with 77% of nests initiated on or before 23 May 2003 (the date used to define “bust” production). Nest success calculated as the average apparent success rate of nests active when first located during initial nest searching (0.68) and the 28-day survival of nests based on exposure days through nest location (0.59) was 0.63—equal to the average nest success of 0.63 observed during the 1990s. Based on these estimates of nest density, clutch size, and nest success, gosling production at Nestor One was approximately 22.21 per 100 ha of wetland—above the average of 16.5 goslings per 100 ha of wetlands observed in the 1990s and estimated production of 11.9 goslings per 100 ha of wetland in 2002. Gosling production at Nestor One in 2003 was above the average observed in the 1990
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    Biennial Report, January 2001 - December 2002
    (2003) Minnesota Cooperative Fish and Wildlife Research Unit
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    FALL SURVIVAL, MOVEMENTS, AND HABITAT USE OF AMERICAN WOODCOCK IN THE WESTERN GREAT LAKES REGION: 2002 FIELD SEASON REPORT
    (2003-07) Andersen, David E; Bruggink, John G; Doherty, Kevin; Lutz, Scott R; Meunier, Jed; Oppelt, Eileen
    Declines in the number of American woodcock (Scolopax minor) heard on annual singing ground surveys have resulted in concern regarding the population status of woodcock in both the Central and Eastern Management Regions. Although changes in the distribution and abundance of woodcock habitat are believed to largely be responsible 1 2002 Field Season Report · July 2003 2 for apparent population declines, relatively little is known regarding the influence of harvest on woodcock population dynamics. Similarly, movements and habitat use of woodcock in fall prior to migration are poorly understood. In 2001 (Minnesota) and 2002 (Michigan and Wisconsin), we initiated a study of woodcock to assess magnitude and causes of woodcock mortality, and investigate movements and habitat use of woodcock in the western Great Lakes Region during fall. In all 3 states, we radio-marked woodcock on paired study areas; one of which was open to woodcock hunting (“hunted areas”) and one of which was closed (“non-hunted areas”) to hunting or had limited access for hunting (“lightly-hunted areas”). In 2002, across all 3 states we captured and radio-equipped 376 woodcock; 203 on hunted areas and 173 on non-hunted or lightly-hunted areas. Survival rates of woodcock during the hunting season in Michigan were 0.839 + 0.270 in the hunted area and 0.909 + 0.219 in the non-hunted area. In Minnesota, the hunting season survival rate of woodcock in the hunted area was 0.764 + 0.140, and in the non-hunted area it was 0.929 + 0.093. In Wisconsin, the hunting season survival rates of woodcock were 0.860 + 0.135 in the hunted area and 0.855 + 0.184 in the lightly hunted area. A sub-sample of after hatch year (AHY) female woodcock was monitored intensively in each state and preliminary analyses of movement and habitat use data from these birds suggest that woodcock make primarily small-scale movements (< 50 m between sequential locations on sequential days and 12.6 ha average 95% fixed kernel home range size) prior to migration. Primary cover types used were aspen seedling/sapling, aspen pole, alder, and conifer. Preliminary analyses also suggest that woodcock used edges within individual covers.
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    BROOD MOVEMENTS AND DISTRIBUTION OF EASTERN PRAIRIE POPULATION (EPP) CANADA GEESE (BRANTA CANADENSIS INTERIOR) IN NORTHERN MANITOBA: POTENTIAL INFLUENCE OF INCREASED SNOW GOOSE (CHEN CAERULESCENS CAERULESCENS) ABUNDANCE
    (2003-07) Nack, Robert, R.
    In 2001 and 2002, we conducted aerial surveys to compare indices of Eastern Prairie Population (EPP) Canada goose (Branta canadensis interior) brood distribution and abundance near Cape Churchill, Manitoba with those obtained in 1977 and 1978. Since the late 1970s, many of the coastal salt marsh areas used for brood-rearing have been degraded as a result of increased foraging pressure from locally breeding and migrating light geese [snow geese (Chen caerulescens) and Ross’s geese (C. rossii)] and the density of nesting Canada geese has declined. The mean Canada goose brood density across the entire survey area in 2001-2002 was not different from 1977-1978 (difference between means ± 95% CI; 0.20 broods/km2 ± 0.36); however, the mean brood density in the southern portion of the survey area was significantly higher in 2001-2002 than in 1977-1978 (0.45 ± 0.39). In 2002, the mean snow goose brood density was higher than the mean Canada goose brood density (27.31 ± 10.92), with higher densities of snow geese in northern coastal flats/beach ridge areas and higher densities of Canada geese in southern coastal flats/beach ridge areas. The mean number of Canada goose broods observed on 15 traditional brood-rearing areas decreased since 1977 (-8.67 ± 6.19) and the mean number of snow goose broods observed increased (43.91 ± 38.22). Canada goose broods appear to have shifted use of brood-rearing areas in response to reduced food availability, direct interactions with snow geese on brood-rearing areas, or both. Loss and degradation of brood-rearing habitat may be a factor in declines in nest density of Canada geese and has implications for EPP management.
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    Fishing in Minnesota: A Study of Angler Participation and Activities
    (2004) Schroeder, Sue; Fulton, David, C.
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    PRODUCTION OF EPP CANADA GEESE NEAR CAPE CHURCHILL IN 2004
    (2004) Andersen, David E. et al
    Nest searching for Eastern Prairie Population Canada geese was conducted on the Nestor One Study Area near Cape Churchill, Manitoba from 16-21 June 2004. A total of 6 nests was found in initial searches of 732 ha of wetlands in 14 primary sample areas, 11 nests were located in searches of 6 coastal sample areas, and 7 nests were located in 3 additional sample units south and east of the primary units. A total of 24 nests was located on the Nestor One study area in 2004. Nest density (unadjusted for observability) in the primary sample areas was 0.82 nests per 100 ha of wetland— the lowest nest density recorded on the Nestor One study site from 1976-2004, and 89% lower than that estimated in 2003. Clutch size in 21 nests with eggs present when located averaged 2.19—lower than the long-term mean of 3.87 (1976-2004) and the clutch size expected based on the established relationship between mean clutch size and median hatch date. Estimated median hatch date was 11 July, and ranged from 7 to 15 July, with no nests initiated on or before 23 May 2004 (the date used to define “bust” production). Nest success calculated as the average apparent success rate of nests active when first located during initial nest searching (0.15) and the 28-day survival of nests based on exposure days through nest location (0.33) was 0.24—considerably lower than the average nest success of 0.63 observed during the 1990s. Based on these estimates of nest density, clutch size, and nest success, gosling production at Nestor One was approximately 0.43 per 100 ha of wetland—the lowest productivity recorded from 1976-2004 and well below the average of 33.48 goslings per 100 ha of wetlands observed during that period.