Squaw Creek National Wildlife Refuge Research Articles

Spatial Ecology and Habitat Use of the Western Foxsnake (Pantherophis vulpinus) on Squaw Creek National Wildlife Refuge (Missouri)

Knowledge of movements, habitat use, and resource requirements is critical to designing management strategies for species with a conservation status. For snakes, basic research needed to derive this information is often lacking or insufficient. We used radio telemetry to investigate the spatial ecology and habitat use of 21 adult Western Foxsnakes (Pantherophis vulpinus) during a single activity season at Squaw Creek National Wildlife Refuge in northwest Missouri, near the species' southern range limit. At the landscape level, monitored snakes located their home ranges in lowland areas in association with wet prairies and managed wetlands but avoided agricultural plots and were not observed to occupy upland areas. Snakes were not selective of macrohabitat within their home ranges but selected microhabitats with denser herbaceous vegetation than typically available at random sites, suggesting that snakes were responding mainly to microhabitat features at the home-range level. Unlike many other temperate snake species, P. vulpinus did not exhibit any sexual differences in selection of microhabitats because all snakes appeared to prefer dense vegetative structure. Home-range sizes were relatively large in comparison to many other terrestrial temperate colubrids and seemed to be explained by resource distribution patterns, such as the proximity of hibernacula and oviposition sites to foraging habitat. Movement patterns varied seasonally among sexes with males demonstrating peak movement distances in May and females in July, respectively. Management decisions to minimize habitat manipulations during the snake activity season and protect embankments used for hibernacula and oviposition will likely benefit Foxsnake conservation.

Spatial Ecology of Breeding Least Bitterns in Northwest Missouri

We examined the spatial ecology of breeding Least Bitterns (Ixobrychus exilis) on Squaw Creek National Wildlife Refuge in northwest Missouri using radiotelemetry. We collected 1,585 locations for 60 individuals (28 males, 32 females) during 23 May–2 August 2005 and 6 June-18 July 2006. Pooled data for both males and females, and both years resulted in mean 50 and 95% fixed kernel home range use distributions of 37.6 (n = 25) and 223.2 ha (n = 25) for all individuals with ≥30 locations. The mean maximum distance traveled between telemetry observations was 2,147.1 m (n = 28). There were no differences in home range size or mobility between male and female Least Bitterns, although there were great variations between years with birds in 2006 using home ranges five times larger than those in 2005. Habitat use was disproportionate to availability with birds using sites with cattail (Typha spp.) and arrowhead (Sagittaria spp.) to a greater extent than available in both 2005 and 2006. One of eight pairs monitored successfully reared young, while females of seven other pairs renested with new mates. Apparent nesting success was low due to severe weather events and nest depredation. We did not observe double brooding. Our study demonstrates that Least Bitterns are capable of using much larger home ranges than previously observed.

Pied-Billed Grebe Nesting Ecology on Squaw Creek National Wildlife Refuge,1996–2007

Pied-billed Grebes (Podilymbus podiceps) are secretive water-birds that build floating nests in smaller wetlands. Our study focused on the nesting ecology, including phenology, of Pied-billed Grebes at Squaw Creek National Wildlife Refuge in northwest Missouri during an 11 year period. We located 956 Pied-billed Grebe nests in wetlands from April to July 1996–2007 and documented the number of eggs in the nest, water depth at the nest, and surrounding vegetation. Using this information, the mean clutch size, mean nest initiation date, mean hatching date, mean water depth at nesting sites, and most common vegetation types surrounding nests were determined and analyzed for differences among years. The mean clutch size for all nests was 7.18 eggs/nest (SE = 0. 09, n = 249) although clutch size significantly varied among years (F=3.51, df=7, P=0.0013). Mean nest initiation date from 414 nests was 18 May while the mean hatching date was 11 June. Both dates were significantly different among years (F=31.86, df=11, P<0.0001 and F=31.93, df=11, P<0.0001). Mean water depth at nest sites was 62.03 cm (SE=0.45, n=561) and varied significantly across years (F=46.50, df= 7, P<0.0001). River bulrush (Schoenoplectus fluviatilis) was the most common vegetation type found at 72.2% of 573 nesting sites followed by arrowhead (Sagitarria latifolia) (23.2%), smartweed (Polygonum sp.) (20.8%), and American lotus (Nelumbo lutea) (19.5%). All Pied-billed Grebe nesting data from Squaw Creek NWR falls within the ranges reported in other nesting studies. It appears current management on the refuge is adequate to support quality Pied-billed Grebe nesting habitat.

Assessment of Allelic Variation Among Massasauga Rattlesnake Populations via Microsatellite Analysis

The decline in populations of the eastern massasauga rattlesnake (Sistrurus catenatus catenatus) across its range is of concern to conservation managers and the species is currently a candidate for federal listing. Because only four eastern massasauga populations are known to occur in Missouri, the species is on the Missouri Endangered Species List. We sought to produce a molecular genetic data set that could be used to inform conservation management decisions about three of these populations. Our method was to collect and analyze data from three microsatellites sites in an effort to provide insight into the genetic health of the populations and into relationships between them. Our method was controlled by inclusion of two populations of the western massasauga (Sistrurus catenatus tergeminus) from southeastern Nebraska. The final data set included 111 individuals from Missouri and Nebraska populations. Although a significant portion (92%) of alleles were shared between each population, low levels of heterozygosity were detected, indicating local inbreeding. Tests of population differentiation suggested that little to no gene flow between these populations has occurred, giving rise to unique allele frequencies and combinations which may be of high conservation value. Most notably, significant differentiation was observed between putative subpopulations at the Squaw Creek National Wildlife Refuge that are in close proximity to one another. Our results illustrate the value of molecular genetics analysis in conservation management and have important implications for the management of Missouri massasauga populations.

Estimating Shorebird Numbers at Migration Stopover Sites

Abstract Abstract We describe a method for estimating the totalnumber of shorebirds that use a migration stopoversite during spring and fall migration. We combinedweekly shorebird counts with parameter estimatesfor detection probability, sampled proportion, andlength of stay on the Squaw Creek National WildlifeRefuge. Double sampling was used to determinedetection probability and estimated values variedamong wetland units from a low of 0.07 to a high of0.82. The sampled proportion of most wetland unitswas 100% but was lower in some of the largerunits. Length of stay (measured for Pectoral[Calidrismelanotos] and LeastSandpipers [C.minutilla] combined)averaged 10.0 days in spring and3.7 days in fall. Spring shorebird numberswere approximately five times greater than fallnumbers on the Refuge. Annual shorebird numbersvaried among years from an estimated low in 2003 of15 734 to a high in 2002 of 69 570.Peak daily counts during study years averaged only12% of estimated spring totals and 4%of fall totals. An estimate of shorebird numbersbased on summing weekly counts, not corrected fordetection probability or sampled proportion, wouldhave been only 21% (spring) to31% (fall) of the total number ofbirds. These results reveal that peak counts andnonadjusted counts can significantly underestimatethe number of shorebirds that use migrationstopover sites in the midcontinent of NorthAmerica.

Effects of Mowing and Summer Burning on the Massasauga (Sistrurus catenatus)

Prescribed fire is used to reduce coverage of woody vegetation in early successional habitats, but burning may also result in direct and indirect mortality of reptiles inhabiting the burn site. Mowing prior to burning has been hypothesized to render grassland habitats unsuitable for the massasauga (Sistrurus catenatus), thereby reducing the number of individuals that may be affected in the management unit at the time of burning. I evaluated the impact of mowing prior to summer burning on massasaugas at Squaw Creek National Wildlife Refuge, in northwestern Missouri, during the summer of 2003 using radiomarked snakes. Pre-burn mowing resulted in the direct mortality of three (43%) of seven radiomarked massasaugas present in the treatment area. Prescribed fire resulted in a mortality of one of two remaining individuals. Pre-burn mowing did not reduce mortalities as hypothesized and likely added to the overall snake mortality rate. Management alternatives other than mowing and prescribed fire when snakes are active should be considered when managing massasauga habitat.

ESTIMATING SHOREBIRD NUMBERS AT MIGRATION STOPOVER SITES

Abstract ABSTRACT We describe a method for estimating the totalnumber of shorebirds that use a migration stopoversite during spring and fall migration. We combinedweekly shorebird counts with parameter estimatesfor detection probability, sampled proportion, andlength of stay on the Squaw Creek National WildlifeRefuge. Double sampling was used to determinedetection probability and estimated values variedamong wetland units from a low of 0.07 to a high of0.82. The sampled proportion of most wetland unitswas 100% but was lower in some of the largerunits. Length of stay (measured for Pectoral[Calidrismelanotos] and LeastSandpipers [C.minutilla] combined)averaged 10.0 days in spring and3.7 days in fall. Spring shorebird numberswere approximately five times greater than fallnumbers on the Refuge. Annual shorebird numbersvaried among years from an estimated low in 2003 of15 734 to a high in 2002 of 69 570.Peak daily counts during study years averaged only12% of estimated spring totals and 4%of fall totals. An es...

Ecology and conservation of an endangered rattlesnake, Sistrurus catenatus, in Missouri, USA

The life history and ecology of the massasauga Sistrurus catenatus, an endangered rattlesnake, was studied from 1979 to 1983 at the Squaw Creek National Wildlife Refuge, Missouri, USA. Except for tail length, this population exhibits little sexual dimorphism. Massasaugas are active from April to October, and are primarily diurnal, except in summer. Snakes are found mainly in a cordgrass prairie in spring and autumn, utilising drier, upland areas in summer. Mean brood size for this population was 6·35, and there was a significant positive relationship between brood size and female body size. Although this species apparently demonstrates considerable geographic variation in reproductive potential, the significance of this variation cannot be currently assessed. Growth rates, estimated from size-frequency data, suggest an age of maturity of 3–4 years for females. Massasaugas at Squaw Creek feed mainly on rodents and other snakes. Current refuge practices, such as controlled burning of the prairie and unrestricted visitor usage, may have significant negative impacts on Sistrurus populations. Recommendations for mitigating these impacts are provided.

Dieldrin Mortality of Lesser Snow Geese in Missouri

In March and April 1974, 157 lesser snow geese (Chen caerulescens) died from dieldrin poisoning during northward migration through western Missouri. Evidence strongly suggested that the mortality in Missouri resulted from delayed effects upon geese exposed to aldrin-treated rice seed on wintering areas in southeast Texas. J. WILDL. MANAGE. 41(1):100-103 From late March to mid-April 1974, widespread mortality of lesser snow geese occurred in western Missouri. Dead birds were found shortly after the arrival of spring migrants, and mortality continued during the peak of northward migration of snow geese through the state. Dead and dying geese were first observed the last week of March at the Schell-Osage Wildlife Area in west-central Missouri. From 1 through 12 April, mortality was observed near Neosho, Newton County, in southwestern Missouri; Schell-Osage Wildlife Area, Vernon and St. Clair counties; Trimble Wildlife Area, Clinton County; and Squaw Creek National Wildlife Refuge, Holt County, in northwestern Missouri. Delayed effects on birds from stored aldrin-dieldrin residues may occur during the stress of migration at considerable distances from areas where the birds were exposed. This paper provides evidence that snow geese died during migration through western Missouri from aldrin-dieldrin poisoning, and that the most probable source of exposure was on wintering areas of southeast Texas. We express our appreciation to R. Vaught, K. Slagle, R. Baskett, and R. Dobbins of the Missouri Department of Conservation for assistance in determining snow goose losses and collecting specimens for examinations. We thank E. L. McCune, University of Missouri, for necropsies and R. Schoettger and D. Stallings, U.S. Fish and Wildlife Service, for chemical analyses of brain tissue samples for pesticides. We also extend appreciation to C. Stutzenbaker, Texas Parks and Wildlife Department, and G. Nugent, U.S. Fish and Wildlife Service for providing snow goose banding data; J. Szymanski and H. Lobpries ,Garwood, Colorado County, Texas, for collecting goose bands from guides and hunters; and personnel of the U.S. Fish and Wildlife Service, Office of Migratory Bird Management, for providing band recovery records for snow

Capturing Waterfowl in Iowa by Night-Lighting

A night-lighting technique was successful in capturing ducks and other marsh birds on shallow Iowa marshes in July and August. In 164 nights of night-lighting from 196 through 1968, 5,084 ducks of 13 species were captured. An average of 31 ducks per night was captured for a catch rate that varied from 4.0 birds per two-man crew hour to 6.6 birds per crew hour. Local birds made up 55 percent, immatures 27 percent, and adults 18 percent of the birds captured. The cost per bird captured varied from $1.10 per bird in 1, to $1.50 per bird in 1967 and 1968. Waterfowl production, weather, and marsh conditions were the three most important variables that determined capture success. 956 Journal of Wildlife Management, Vol. 33, No. 4, October 1969 ( Anser albifrons ) after individual release. Bird-Banding 36 ( 3 ) :18>191. NASS, R. D. 1964. Sexand age-ratio bias of cannon-netted geese. J. Wildl. Mgmt. 28 ( 3 ): 522 527. RAVING, D. G. 1966. Factors affecting age ratios of samples of Canada geese caught with cannon-nets. J. Wildl. Mgmt. 30 ( 4 ): 682-691. . 1969a. Social cIasses of Canada geese in winter. J. Wildl. Mgmt. 33(2):304-318. . 1969b. Roost sites and flight patterns of Canada geese in winter. J. Wildl. Mgmt. 33 ( 2 ): 319-330. SCHI0LER, E. L. 1924. Om de skandinviske aeunder, deres dragtskifte og traek. Dansk. Om. Tids. Kjbenhaven 18:85-95. SHERWOOD, G. A. 1967. Behavior of family groups of Canada geese. Trans. N. Am. Wildl. and Nat. Resources Gonf. 32: 340L355. VAUGHT, R. W., AND H. BIJRGESS. 1966. The 1966 progress report on goose management at Squaw Creek National Wildlife Refuge, Missouri. 33pp. Mimeo. , AND L. M. KIRSCH. 1966. Canada geese of the Eastern Prairie population, with special reference to the Swan Lake flock. Missouri Dept. Conserv. Tech. Bull. No. 3. 91pp. Received for publication May 5, 1969. This paper describes night-lighting equipment and subsequent captllre results of waterfowl in Iowa. The technique of nightlighting is an old practice. Reeves (1966) and Drewien et al. (1967) sumrnarized the history of night-lighting. Other writers have reported their efforts using this technique on waterfowl (Lindmeier and Jessen 1961, Cummings and Hewitt 1964) Lovrien 1965, Drewien et al. 1967). The reported techniques vary as to equipment, time of year, species of birds capturedn and types of habitat worked, but all authors verify that it is a successful method of captunng water birds and pheasants (Phasianus colchicus). We wish to thank R. Howing, Unit Game Manager of the Iowa Conservation Commission, for his help in improving this operation and for assistance in capturing wa-

Fowl Cholera in Waterfowl at Squaw Creek National Wildlife Refuge, Missouri

An epizootic of fowl cholera (Pasteurella multocida), in lesser snow geese (Chen h. hyperborea), blue geese (Chen caerulescens), mallards (Anas platyrhynchos), and other waterfowl occurred on Squaw Creek National Wildlife Refuge, Holt County, Missouri, during early January, 1964. More than 1,000 geese died in one night. Symptoms and previous case histories of fowl cholera, an infrequently reported disease among wild waterfowl, are reviewed. Pertinent field observations and methods of diagnosis are described. Observations indicated that mallard ducks were the probable early carriers of the disease. Snow, blue, and small Canada geese (Branta c. hutchinsii) were quite susceptible while large Canada geese (Branta c. interior and maxima) were not involved. Stresses caused by limited open water, overcrowding of birds, and inclement weather may have been conducive to the epizootic. Direct mortality from fowl cholera on wintering areas is not indicative of total mortality. Losses may continue along the migration routes. Secondary effects may result in loss of productivity. This paper describes an epizootic of fowl cholera (Pasteurella multocida) in lesser snow and blue geese and other waterfowl on Squaw Creek National Wildlife Refuge, Holt County, Missouri, during late 1963 and early 1964. Fowl cholera is a serious disease of domestic fowl, but it is infrequently reported as an epizootic disease of wild waterfowl. The earliest documented record of fowl cholera in wild ducks was reported by Quortrup et al. (1946) in Texas. Petrides and Bryant (1951) reported that periodic outbreaks of fowl cholera among ducks have occurred there since. The largest reported losses occurred in California where Sperry (1949 unpublished report filed at Patuxent Wildlife Research Center, Laurel, Maryland) estimated a die-off of 36,000 ducks. Rosen and Bischoff (1950) reported losses of coots, ducks, and gulls to Pasteurella multocida over a broad coastal area near San Francisco Bay. More recently, in Maine, a fowl cholera outbreak in eider ducks (Somateria mollissima) was reported by Gershman et al. (1964). The absence of signs of disease before death from fowl cholera has been recorded in numerous cases. Curtice (1902) reported a case in domestic geese where some specimens in prime condition were found dead with scarcely any appearance of previous sickness. Quortrup et al. (1946:99) observed that 10 minutes before death, ducks were apparently in good health except that normal reflexes were not as sensitive as in healthy birds, and they did not become frightened so easily. They also noted, Many birds died with their heads up in a natural sitting position and rigor mortis was immediate. Rosen and Bischoff (1949: 186) observed ducks in normal flight or in loafing attitudes, or else the carcasses were seen floating on the ponds or lying along the shoreline. Barger et al. (1958) reported that, when the disease was very acute, the first indication of infection was the finding of dead chickens that had not shown any signs before death. They also found that ex1 This project was supported by Federal Aid to Wildlife Restoration, Surveys and Investigation Projects, Missouri 13-R; by funds from the Department of Veterinary Microbiology, University of Missouri; and by funds from the Bureau of Sport Fisheries and Wildlife, Squaw Creek National Wildlife Refuge.