Michael C. Zicus

Relationships of habitat patch size to predator community and survival of duck nests

We studied duck nest success and predator community composition in relation to size of discrete patches of nesting cover in the Prairie Pothole Region (PPR) of the United States in 1993-95 We focused on nests in uplands that were seeded to perennial grasses and forbs and enrolled in the Conservation Reserve Program (CRP) in Minnesota, North Dakota, and South Dakota. We estimated daily survival rates (DSRs) of upland duck nests and indices of activity for red foxes (Vulpes vulpes), coyotes (Canis latrans), American badgers (Taxidea taxus), striped skunks (Mephitis mephitis) and Franklins ground squirrels (Spermophilus franklinii) and related these variables to habitat patch size. The effect of patch size (small vs. large) on estimated annual mean DSR was dependent on date of nest initiation (early vs. late) and year. Examination of within-year comparisons for early and late nests suggested that DSR was generally greater in larger habitat patches Activity indices for the 5 mammalian nest predators were influenced differently by year, location, and patch size. Activity indices of the red fox were greatest in small patches. Coyote indices were the most inconsistent, demonstrating a year × location × patch size interaction. Activity indices of the striped skunk and American badger varied only among years. Franklins ground squirrel indices were affected by study area location, with higher indices in the southeast than the northwest. Red fox activity was weakly correlated with that of the striped skunk and coyote. Although a positive relationship between habitat patch size and nest success probably exists, we believe the experiment to fully test this hypothesis will continue to be elusive.

Common Goldeneye nest attendance patterns

Common Goldeneye (Bucephala clangula) nest attendance was recorded on three Minnesota lakes, 1982-1985. Data were from 22 nests monitored 545 days. Hens increased time at nests and frequency of overnight sessions as incubation approached. Incubation recesses were diurnal; most occurred between 9:00 and 19:00 CST. Recesses were fewest and longest in early incubation, but total recess time was greatest in late incubation. Daily incubation constancy was highly variable, ranging from 36.7 to 96.3%. Lake and year effects influenced the number of daily recesses and total daily recess time. Mean recess length did not differ among lakes and years. Three females monitored in both 1984 and 1985 recessed more daily (χ = 55 min) in 1984, and their yearly ranks were the same for all parameters suggesting strong hen effects. Incubation ranged from 28 to 30 days and was correlated (r = 0.72) with mean daily recess time. Nests incubated 29 and 30 days had mean total incubation times that differed by 13 min. While brooding young, incubation-like patterns were maintained but absences were fewer and shorter. Our results differed slightly from those reported for a recent Ontario study, but the differences may be due to analytical approaches

Nesting biology of hooded mergansers using nest boxes

I studied nesting by hooded mergansers (Lophodytes cucullatus) using nest boxes in an area of northcentral Minnesota having no previous nest box management. Boxes were scattered with a median density of about 0.8 boxes per km 2 , and from 39 to 87 nest boxes were examined yearly. Nearly half of the boxes contained merganser eggs each year; nest density was approximately 0.4 nests per km 2 . The proportion of nests that was incubated by mergansers did not vary among years and averaged 77.5±2.8 (SE)%. In contrast, the proportion of merganser eggs laid that was incubated varied yearly (P 13 eggs, and the average clutch size (13) exceeded that observed in other studies where nest box densities were greater. Most females changed nest sites in subsequent years; 9 to 13 movements were >1.0 km. Intraspecific laying in a single nest was common and appeared to be related more to hooded merganser abundance than to nest box density and distribution

Fall Flock Behavior and Harvest of Canada Geese

We studied fall flock behavior and harvest of locally breeding Canada geese (Branta canadensis) and those that use the area as a migration stopover at the Talcot Lake Wildlife Management Area (TLWMA) in southwest Minnesota in 1980-81. We used neckbands and radio transmitters to measure movements and survival of geese. We conducted aerial and ground surveys to estimate the size of goose populations. The 800-ha TLWMA refuge provided hunting season sanctuary for geese breeding in a 1,500-km2 area surrounding the refuge. Fidelity of local geese to feeding and roosting sites was strong throughout the fall. Prehuntingseason flight patterns to feeding sites off the refuge continued despite heavy hunting pressure. Marked families from a given brood-rearing site fed and roosted together at rates greater than would have been expected by chance. This subflock behavior, combined with consistent flight patterns, resulted in differential mortality among brood-rearing groups. In contrast, migrants remained at TLWMA briefly, fed independently from local geese when off the refuge, and were harvested at a lower rate (P < 0.05) than local geese. J. WILDL. MANAGE. 52(4):679-688 The giant Canada goose (B. c. maxima) has been restored over much of its former midwestern range (Nelson 1963, Brakhage 1965, Dill and Lee 1970, Cooper 1978). This race has steadily increased to an estimated 108,000 birds in the Mississippi Flyway in 1981 (U.S. Fish and Wildl. Serv. and Can. Wildl. Serv. 1982). Although less numerous than subarctic and arctic goose populations (Bellrose 1976), resident populations of giant Canada geese provide recreation where geese were once rare or absent (Hine and Schoenfeld 1968). Management programs for local geese have included establishing additional populations, improving breeding habitat, and establishing refuges. Refuges have also contributed to an increase in subarctic and arctic nesting Canada geese stopping in the upper midwest (Vaught and Kirsch 1966, Reeves et al. 1968). Concurrent use of refuges by migrant geese and locally breeding geese is common. Goose concentrations on refuges have resulted in high hunter densities, firing lines, and crop depredations. These issues, and a goal to apportion the harvest of geese equitably in the Mississippi Flyway, have led to a search for methods to distribute migrant geese (Reeves et al. 1968). Sherwood (1968) identified hunting as an important limiting factor for restored populations; therefore, techniques are needed for managing the harvest of migrant and locally breeding geese concurrently using a refuge. An understanding of the behavior of migrant and resident geese during fall is necessary to attain this objective. Migratory and wintering subpopulations or subflocks of Canada geese have been described by Kennedy and Arthur (1974), Koerner et al. (1974), and Raveling (1969, 1978, 1979). Zicus (1981a) documented subflock behavior on the breeding grounds in summer and fall. Zicus (1981a) suggested that resident geese rearing young at specific sites associated with each other and differed from other subflocks in their use of a refuge for feeding and roosting; he speculated that subflocks may differ in their vulnerability to hunting. Our study examined behavior of resident and migrant Canada geese using a refuge concurrently during fall in southwest Minnesota. We studied chronological changes in size and composition of migrant and local flocks, use of feeding sites, family associations and mortality rates among local geese, composition of the Canada goose harvest, and factors affecting vulnerability of these geese to hunting. We thank J. R. Kitts and F. B. Martin, University of Minnesota, for reviewing the manuscript and for assisting with statistical procedures, respectively. R. J. Peterson, J. G. Beech, D. G. Opdahl, L. M. Koster, E. L. Larson, and other personnel of the Minnesota Department of Natural Resources (MDNR) helped with banding, observations, and bag checks. Additional banding assistance was provided by S. J. 1 Present address: Section of Wildlife, Minnesota Department of Natural Resources, 231 E. Second Street, Redwood Falls, MN 56283.

Factors influencing incubation egg-mass loss for three species of waterfowl

Abstract Many bird eggs lose ∼15% of their fresh mass before pipping, but individual species have been reported to lose 10–23%. Most published estimates have been imprecise due to small sample sizes. Moreover, published estimates of within- or among-species variance components of mass loss are virtually unknown. We modeled the influence of nest type, clutch size, and egg size on daily mass loss of Mallard (Anas platyrhynchos), Common Goldeneye (Bucephala clangula), and Hooded Merganser (Lophodytes cucullatus) eggs and compared fractional mass loss among species. Mallard eggs in artificial nest cylinders lost more mass than those in ground nests, but were unaffected by nest initiation date. Average-sized eggs in Mallard ground nests, Mallard cylinder nests, and Common Goldeneye and Hooded Merganser nest boxes lost 7.9 g (15.2%), 10.8 g (20.3%), 10.3 g (15.5%), and 9.2 g (15.8%) of fresh mass, respectively. For all species, daily mass loss increased as incubation progressed and was affected by an interaction between egg size and incubation time, but was not influenced by clutch size. Depending on species, smallest eggs lost 1.0–4.0% more of their fresh mass than did the largest. Egg-mass variability was partitioned into years, nests within years, and eggs within nests and years. Variability was evenly distributed among the variance components in Mallard ground nests; however, among-eggs within-nest variance predominated in nest cylinders. In contrast, among-nests variation was the dominant source for goldeneyes and mergansers. Nest-site selection and egg size likely involve trade-offs among optimum egg-mass loss and nest and hatchling survival. Factores que Influencian la Pérdida de Peso de los Huevos durante la Incubación en Tres Especies de Aves Acuáticas Resumen. Muchas aves pierden aproximadamente el 15% de su peso fresco antes de iniciar la ruptura del cascarón, pero se ha reportado que esto varía entre especies entre el 10 y el 23%. La mayoría de los estimados publicados han sido imprecisos debido a tamaños de muestra pequeños. Más aún, los estimados de los componentes de la varianza dentro de especies o entre especies en la pérdida de peso son virtualmente desconocidos. En este estudio modelamos la influencia del tipo de nido, el tamaño de la nidada y tamaño del huevo sobre la pérdida diaria de peso en huevos de Anas platyrhynchos, Bucephala clangula y Lophodytes cucullatus, y comparamos la fracción de peso perdida entre especies. Los huevos de A. platyrhynchos perdieron más peso en nidos cilíndricos artificiales que en nidos en el suelo, pero no fueron afectados por la fecha de iniciación de la nidificación. Huevos de tamaño promedio de A. platyrhynchos puestos en nidos en el suelo y en cilindros, y huevos de B. clangula y L. cucullatus puestos en cajas de nidificación, perdieron 7.9 g (15.2%), 10.8 g (20.3%), 10.3 g (15.5%) y 9.2 g (15.8%) de su peso fresco, respectivamente. Para todas las especies, la pérdida diaria de peso se incrementó a medida que progresó la incubación y fue influenciada por una interacción entre el tamaño de los huevos y el tiempo de incubación, pero no por el tamaño de la nidada. Dependiendo de la especie, los huevos más pequeños perdieron entre 1.0 y 4.0% más de su peso fresco que los huevos más grandes. La variabilidad en el peso de los huevos estuvo repartida entre años, entre nidos de un mismo año y entre huevos de un mismo nido en cada año. La variabilidad estuvo igualmente distribuida entre sus distintos componentes en los nidos de A. platyrhynchos del suelo. Sin embargo, la varianza entre huevos de un nido predominó en los nidos puestos en cilindros. En contraste, la variación entre nidos fue la más importante en B. clangula y L. cucullatus. La selección de sitios de nidificación y el tamaño de los huevos probablemente involucran una solución de compromiso entre los niveles óptimos de pérdida de peso de los huevos y de supervivencia de los nidos y pichones.

DOES MALLARD CLUTCH SIZE VARY WITH LANDSCAPE COMPOSITION: A DIFFERENT VIEW

Abstract We report on the relationship between Mallard (Anas platyrhynchos) clutch size and cropland area in the landscape in western Minnesota during 1997–1999. We measured clutch size in two types of nest structures and fit a mixed-effects model to the data to examine the relationship. Our model also included covariates to control for the effects of year, nest initiation date, estimated pair numbers, and nest structure type. Unique landscapes associated with each nest (n = 134) ranged from 46.4–84.8% cropland. Clutch size was unrelated to cropland area, nest structure type, and estimated number of pairs with access to structures. Mean clutch size declined with nest initiation date early in the nesting season, but increased somewhat for nests initiated after 30 May. Clutch size also differed among years. Mean clutch size, adjusted for nest initiation date, was 11.0 ± 0.19 SE for 1997, 10.5 ± 0.19 SE for 1998, and 11.0 ± 0.19 SE for 1999. Conclusions regarding the significance of the year effect and the degree of nonlinearity due to nest initiation date were sensitive to potential clutch size outliers, but cropland area had no effect on clutch size regardless of the way we constrained clutch size. Nest parasitism by philopatric females laying in certain structures might explain the observed increase in clutch size in late nest initiations.

Cost and Precision Functions for Aerial Quadrat Surveys: a Case Study of Ring-Necked Ducks in Minnesota

Abstract Cost considerations may be as important as precision when making survey-design choices, and the ability to accurately estimate survey costs will be essential if survey budgets become more constrained. We used data from a survey of ring-necked ducks (Aythya collaris) to illustrate how simple distance formulas can be used to construct a cost function for aerial quadrat surveys. Our cost function provided reasonable estimates of effort (hr) and costs, and allowed us to evaluate plot-size choices in terms of expected cost-precision tradeoffs. Although factors influencing costs in wildlife surveys can be complicated, we believe that cost functions deserve more attention and should be routinely considered in conjunction with traditional power analyses.

Influence of Land Use on Mallard Nest-Structure Occupancy

Abstract We investigated the relationship between land use and mallard (Anas platyrhynchos) occupancy of single- and double-cylinder nest structures on a 658-km2 (254-mile2) western Minnesota, USA, study area from 1997–1999. We used hierarchical logistic regression to spatio-temporally model structure occupancy as a function of land use, number of nearby structures, number of mallard pairs with access to the structure, size of the open-water area including the structure, and structure type. We fit models to data from 4 different-sized buffers around each structure to investigate scale influences. Goodness-of-fit, predictive ability, and amount of reduced spatio-temporal correlation were similar for each buffer-size model. We made inferences using the 1.6-km-radius buffer model because it produced the lowest deviance. The amount and attractiveness of nesting cover (i.e., as indexed by visual obstruction measurements [VOMs]) within a buffer interacted with nest-initiation period (P = 0.003). The VOMs and nest occupancy were positively associated early in the nesting season, but the pattern reversed later in the nesting season. Structure occupancy and area of open water around a structure were related quadratically (P = 0.004), with odds of a structure in median-sized open-water areas being occupied increasing until the open-water area was ~16 ha. Year and nesting-season period interacted (P = 0.002), reflecting different nest-initiation phenology. Number of pairs with access to a structure had no effect on nest initiations (P = 0.7), perhaps due to our inability to account for within-season changes in pair numbers. Number of nearby structures (P = 0.8) was unrelated to initiation probability, but structure density was low (0.05/km2). We suspect that mallard settling patterns and an unmeasured temporal relationship between VOMs and numbers of pairs with access to structures produced the VOM × period interaction. Structures deployed in larger open-water areas where surrounding residual upland cover is abundant can improve mallard nest success early in the nesting season when duckling survival is the greatest and can reduce hen mortality associated with nest destruction and re-nesting.

Flock Behavior and Vulnerability to Hunting of Canada Geese Nesting at Crex Meadows, Wisconsin

Fall movement and survival of 64 Canada goose (Branta canadensis) families within a flock re-established in a 579-km2 area closed to Canada goose hunting were studied in 1972 and 1973. Distinct groups of families (subflocks) formed from 5 different brood-rearing areas. On attaining flight, families in different subflocks first fed in fields closest to the marshes from which they fledged. Later, more distant fields were used, but subflocks continued to feed separately. Geese roosted in marshes nearest their feeding sites during the entire period. Hunting pressure caused families feeding outside the refuge area to change fields, but subflock composition and roosting locations were unchanged. Shallow marsh freezeup altered subflock composition, distribution of feeding geese, and roosting locations. Geese in subflocks feeding most often in the refuge were least vulnerable to hunting, and appeared to have the lowest local mortality. Two subflocks also had different wintering areas. Geese in a subflock migrating and wintering east of the Mississippi River were reported shot more often than those to the west. These results demonstrate the need to understand subflock behavior before assessing survival in local populations. J. WILDL. MANAGE. 45(4):830-841 Restoration of nesting Canada geese where they were eliminated because of habitat loss and overharvest has become common, and many reestablishments have been reported (Brakhage 1965, Dill and Lee 1970, Cooper 1978). Although the welfare of these geese depends on effective management throughout the year, many local goose populations are limited by local hunting (Sherwood 1968:82-84). Understanding fall behavior of local geese in relation to habitat and refuge needs and hunting season vulnerability is essential for their optimum management. The flock behavior of giant Canada geese (B. c. maxima) nesting on the Crex Meadows Wildlife Management Area was investigated in autumn 1972 and 1973 and in spring 1974. Objectives were to examine: (1) impact of fall hunting seasons and marsh freeze-up on the feeding and roosting patterns of resident pairs and their young of the year, (2) relationship of flock behavior to local hunting vulnerability, and (3) relationships between flock behavior and migration routes, wintering areas, and nonlocal mortality. W. H. Marshall and J. A. Cooper made suggestions during the study and reviewed the manuscript, and N. R. Stone, J. O. Evrard, and other employees of the Wisconsin Department of Natural Resources provided valuable assistance in the field. University of Minnesota graduate students, A. H. Grewe, and students from St. Cloud University helped capture the geese banded in this study. D. Heisey helped with the statistical treatments, and V. Hellquist typed numerous drafts of the manuscript. Financial support was provided by a National Defense Education Assistantship, the Malvin E. and Josephine D. Herz Foundation, Daytons Natural History Fund, and the Department of Entomology, Fisheries, and Wildlife, University of Minnesota. The Malvin E. and Josephine D. Herz Foundation also provided funds for publication of the study results. Present address: Minnesota Department of Natural Resources, Wetland Wildlife Populations and Research Group, 102 23rd Street, Bemidji, MN 56601. 830 J. Wildl. Manage. 45(4):1981 This content downloaded from 207.46.13.184 on Fri, 29 Jul 2016 04:30:44 UTC All use subject to http://about.jstor.org/terms CANADA GEESE AT CREX MEADOWS * Zicus 831

Cost‐Effectiveness of Single‐ Versus Double‐Cylinder Over‐Water Nest Structures

Abstract Minnesota waterfowl management plans prescribe widespread deployment of mallard (Anas platyrhynchos) nest structures. We compared 53 single- and 57 double-cylinder nest structures from 1996 to 2003 because managers used both structure types but were uncertain about their respective cost-effectiveness. More nests occurred in double-cylinder structures, but numbers of successful nests and hatched ducklings were comparable for both types. Nest success in single- and double-cylinder structures was 92.8% and 79.4%, respectively, with nest abandonment being >4.5 times greater in doubles. Structure damage occurred only at ice-out and was greater for doubles. However, relative risk of failure for double- versus single-cylinder structures was similar (1.26; 95% CI = 0.91–1.75) and increased with size of the open-water area containing the structure. Modeling indicated approximately 95% of recruits from nest structures were additional recruits. A case-history approach indicated doubles produced an additional recruit for