Jerry W. Hupp

Questionable multivariate statistical inference in wildlife habitat and community studies (a reply)

We analyzed a data set constructed from functionally unrelated, easily collected observations (e.g., meat, stock, and liquor prices) around Fort Collins, Colorado, using principal components analysis (PCA), canonical correlation analysis (CC), and discriminant function analysis (DFA). Each produced seemingly significant results and suggested strong relationships between the variables measured. We suggest that multivariate techniques can provide invalid inferences when used with data containing no relationships. We question the use of these techniques in studies of wildlife habitat.

A NEW SPECIES OF SAGE-GROUSE (PHASIANIDAE: CENTROCERCUS) FROM SOUTHWESTERN COLORADO

Abstract The Gunnison Sage-Grouse (Centrocercus minimus) is described as a new species from southwestern Colorado and contrasted with the Sage-Grouse (Centrocercus urophasianus) from northern Colorado and western North America. Gunnison Sage-Grouse differ from all other described sage-grouse (C. u. urophasianus, C. u. phaios) in morphological measurements, plumage, courtship display, and genetics. The species currently is limited to 8 isolated populations in southwestern Colorado and adjacent San Juan County, Utah. Total estimated spring breeding population is fewer than 5000 individuals with the largest population (<3000) in the Gunnison Basin (Gunnison and Saguache counties), Colorado.

Interspecific exchange of avian influenza virus genes in Alaska: the influence of trans-hemispheric migratory tendency and breeding ground sympatry

The movement and transmission of avian influenza viral strains via wild migratory birds may vary by host species as a result of migratory tendency and sympatry with other infected individuals. To examine the roles of host migratory tendency and species sympatry on the movement of Eurasian low‐pathogenic avian influenza (LPAI) genes into North America, we characterized migratory patterns and LPAI viral genomic variation in mallards (Anas platyrhynchos) of Alaska in comparison with LPAI diversity of northern pintails (Anas acuta). A 50‐year band‐recovery data set suggests that unlike northern pintails, mallards rarely make trans‐hemispheric migrations between Alaska and Eurasia. Concordantly, fewer (14.5%) of 62 LPAI isolates from mallards contained Eurasian gene segments compared to those from 97 northern pintails (35%), a species with greater inter‐continental migratory tendency. Aerial survey and banding data suggest that mallards and northern pintails are largely sympatric throughout Alaska during the breeding season, promoting opportunities for interspecific transmission. Comparisons of full‐genome isolates confirmed near‐complete genetic homology (>99.5%) of seven viruses between mallards and northern pintails. This study found viral segments of Eurasian lineage at a higher frequency in mallards than previous studies, suggesting transmission from other avian species migrating inter‐hemispherically or the common occurrence of endemic Alaskan viruses containing segments of Eurasian origin. We conclude that mallards are unlikely to transfer Asian‐origin viruses directly to North America via Alaska but that they are likely infected with Asian‐origin viruses via interspecific transfer from species with regular migrations to the Eastern Hemisphere.

Effects of Abdominally Implanted Radiotransmitters with Percutaneous Antennas on Migration, Reproduction, and Survival of Canada Geese

Abstract Abdominally implanted radiotransmitters with percutaneous antennas are increasingly used to monitor movements, survival, and reproduction of waterbirds. However, there has been relatively little assessment of the effects of such radios on avian demographic parameters or migration. We implanted either a 26- or 35-g abdominal transmitter with percutaneous antenna in 198 adult female lesser Canada geese (Branta canadensis parvipes) in Anchorage, Alaska during 2000 and 2001. We compared migration chronology, reproductive effort, and survival of radiomarked females to 118 control females marked with leg bands. Arrival dates following spring migration were similar among females in different treatments in 2001. However, in 2002, wind direction during late migration was less favorable, and arrival of females with 35-g radiotransmitters lagged 1–2 days behind that of control females. Nest initiation dates, clutch size, and mean egg volume were similar for 152 nests of females that lacked radios and 62 nests of radiomarked females. Estimated nesting propensity for females with operable radiotransmitters was 61% and 72% in 2001 and 2002, respectively. Apparent annual survival (φ = 0.82, 95% confidence interval: 0.76 to 0.87) was similar among treatments in the first year after geese were marked. In the second and third years after marking, model-averaged estimates for survival of females with large radiotransmitters were 10% lower than estimates for control females. However, the effect of large radios on long-term survival was equivocal because of uncertainty surrounding treatment estimates. We conclude that abdominally implanted radiotransmitters with percutaneous antennas had small effects on migration chronology but no apparent effects on fecundity. Abdominal transmitters can provide unbiased estimates of anserine survival in the first year after deployment. Because of the potentially greater effects of larger transmitters on migration and long-term survival, we recommend that biologists minimize the size of implanted transmitters and deploy radios with caution if long-term survival of marked birds is a concern.

Forage digestibility and intake by lesser snow geese: effects of dominance and resource heterogeneity

AbstractWe measured forage intake, digestibility, and retention time for 11 free-ranging, human-imprinted lesser snow geese (Chen caerulescens caerulescens) as they consumed underground stembases of tall cotton-grass (Eriophorum angustifolium) on an arctic staging area in northeastern Alaska. Geese fed in small patches (

LINE TRANSECT ESTIMATES OF DENSITY AND THE WINTER MORTALITY OF GRAY PARTRIDGE

\bar x

THE PRELAYING INTERVAL OF EMPEROR GEESE ON THE YUKON-KUSKOKWIM DELTA, ALASKA

=21.5 m2) of forage that made up ≤3% of the study area and consisted of high-quality “aquatic graminoid” and intermediate-quality “wet sedge” vegetation types. Dominant geese spent more time feeding in aquatic graminoid areas (r=0.61), but less total time feeding and more time resting than subdominant geese. Subdominant geese were displaced to areas of wet sedge where cotton-grass was a smaller proportion of underground biomass. Geese metabolized an average of 48% of the organic matter in stembases and there was a positive correlation between dominance and organic matter metabolizability (r=0.61). Total mean retention time of forage was 1.37 h and dry matter intake was 14.3 g/h. Snow geese that stage on the coastal plain of the Beaufort Sea likely use an extensive area because they consume a large mass of forage and exploit habitats that are patchily distributed and make up a small percentage of the landscape. Individual variation in nutrient absorption may result from agonistic interactions in an environment where resources are heterogeneously distributed.

Seasonal Survival of Radiomarked Emperor Geese in Western Alaska

Gray partridge (Perdix perdix) habitat use was studied in eastern South Dakota by monitoring 46 radio-tagged birds between 22 December 1978 and 21 August 1980. Partridge coveys used pastures in a winter with deep snow (56 cm, 1979) and row crops in a winter with little snow (4 cm, 1980). During spring dispersal, partridge used many different habitat types. Idle habitat (roadside, fencerows, shelterbelts) was used in late spring during the nesting period and small grain crops in early summer as broodrearing cover. Partridge used standing row crops during late summer after small grain harvest. They continued to use row crops after fall harvest. Partridge did not use different habitat types during 3 diurnal time periods. Mean home range was 96 ha (N = 8); however, individual home ranges were variable (SD = 110.6). Variability in home range may be related to season, weather, and stage in the partridge life cycle. J. WILDL. MANAGE. 46(3):580-587 Gray partridge are becoming more important as a game species in the northern prairies. In South Dakota, hunter harvest of partridge increased from 3,125 birds in 1970 to 69,170 in 1978 (South Dakota Dep. Game, Fish and Parks, unpubl. rep., 1980). Although partridge are an important wildlife resource, few data are available on their ecology in South Dakota. The objectives of this study were to examine seasonal habitat use and home range size of gray partridge in eastern South Dakota. We thank W. L. Tucker and G. C. White for assisting with statistical analysis and J. E. Dunn for providing the home range program. K. McElvain provided assistance with computer programming. W. Balda, D. Doudna, B. Gehring, J. Jasmer, E. Keyser, and D. Lundborg assisted with field work and R. P. Davison, L. D. Flake, C. G. Scalet, J. P. Weigand, and W. A. We tz reviewed drafts of the manuscript. We thank the study area landowners for their support and L. Ratti for editorial suggestions.