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Geology topics

Craig R. Ely

Publications and source records attributed to Craig R. Ely.

54 records · Page 3Linked to original sources
USGS2002

Nesting ecology of tundra swans on the coastal Yukon-Kuskokwim Delta, Alaska

Nesting ecology of Tundra Swans (Cygnus columbianus columbianus) was studies the Kashunuk River near Old Chevak (61A?26a??N, 165A?27a??W), on the Yukon-Kuskokwim Delta of western Alaska from 1988-2000. Annual variation in snow-melt chronology, nesting phenology, nesting density, clutch size and nest success was examined. The same area (approximately 23 kmA?) was searched each year and nests were found as early as possible in the laying period. Laying initiation dates ranged from 1-27 May and hatch dates from 12 June a?? 4 July among pairs and years of study. The peak arrival of Tundra Swans and the phenology of nest initiation and hatch were highly correlated with the progression of ice and snow melt in spring. Nest density averaged 0.71 kmA? and 89% of nesting pairs hatched at least one egg. Incubation period ranged from 26 to 33 days with a median of 30 days. Clutch size varied significantly among years, driven by a low mean value of 3.4 eggs in 1999. Clutch sizes were generally larger than found in previous investigations on the Yukon-Kuskokwim Delta, and nearly one egg larger than reported for clutches from Alaskaa??s North Slope (=70A?N). There was no indication of reduced clutch size in years of late spring snow melt, although nesting density tended to be lower.

Waterbirds↗
USGS2001

Topography and flooding of coastal ecosystems on the Yukon-Kuskokwim Delta, Alaska: Implications for sea level rise

We measured surface elevations, stage of annual peak flooding, and sedimentation along 10 toposequences across coastal ecosystems on the Yukon-Kuskokwim (Y-K) Delta in western Alaska during 1994-1998 to assess some of the physical processes affecting ecosystem distribution. An ecotype was assigned to each of 566 points, and differences in elevations among 24 ecotypes were analyzed within individual toposequences and across the 40 x 40-km study area. Elevations of vegetated ecotypes along the longest toposequence rose only ~1 m over a distance of 7.5 km, and mean elevations of most ecotype across the study area were within 0.5 m of mean higher-high water (1.47 m). During 1994 to 1998, monitoring of annual peak stage using crest gauges revealed flooding from the highest fall storm surge reached 2.58 m (1.11 m above mean higher-high tide). In each year, only the highest surface was unaffected by flooding. Mean annual sedimentation rates for the various ecotypes were 8.0 ram/y on tidal flats, 1.4 to 3.8 mm/y on the active floodplain, 0.1-0.2 mm/y on the inactive floodplain, and 0 mm/ on the abandoned floodplain. If sea levels in the Bering Sea rise ~0.5 m by 2100, as predicted by some on a global basis, large portions of the coastal margin of the delta could be regularly inundated by water during high tides, and even the highest ecotypes could be affected by storm surges. Predicting the extent of future inundation is difficult, however, because of the changes in the ground-surface elevation through sedimentation, organic matter accumulation, and permafrost development.

Alaska↗
USGS1999

Behavioral correlates of heart rates of free-living Greater White-fronted Geese

We simultaneously monitored the heart rate and behavior of nine free-living Greater White-fronted Geese (Anser albifrons) on their wintering grounds in northern California. Heart rates of wild geese were monitored via abdominally-implanted radio transmitters with electrodes that received electrical impulses of the heart and emitted a radio signal with each ventricular contraction. Post-operative birds appeared to behave normally, readily rejoining flocks and flying up to 15 km daily from night-time roost sites to feed in surrounding agricultural fields. Heart rates varied significantly among individuals and among behaviors, and ranged from less than 100 beats per minute (BPM) during resting, to over 400 BPM during flight. Heart rates varied from 80 to 140 BPM during non-strenuous activities such as walking, feeding, and maintenance activities, to about 180 BPM when birds became alert, and over 400 BPM when birds were startled, even if they did not take flight. Postflight heart rate recovery time averaged < 10 sec. During agonistic encounters, heart rate exceeded 400 BPM; heart rates during social interactions were not predictable solely from postures, as heart rates were context-dependent, and were highest in initial encounters among individuals. Instantaneous measures of physiological parameters, such as heart rate, are often better indicators of the degree of response to external stimuli than visual observations and can be used to improve estimates of energy expenditure based solely on activity data.

Condor↗
USGS1996

Geographic variation in migratory behavior of greater white-fronted geese ( Anser albifrons )

We studied the migration and winter distribution of adult Greater White-fronted Geese ( Anser albifrons frontalis ) radio-marked on the Yukon-Kuskokwim Delta (YKD) and Bristol Bay Lowlands (BBL) of Alaska from 1987 to 1992. The major autumn staging site for geese from both breeding areas was the Klamath Basin on the California/Oregon border. However, temporal use of this area differed markedly between populations. Geese from the BBL arrived at the Klamath Basin nearly 30 days before geese from the YKD and departed before most YKD geese had arrived. Ninety percent of BBL geese used the Klamath Basin in autumn, whereas 30% of YKD geese bypassed the Klamath Basin during autumn and instead flew directly to the Central Valley of California. Nearly all BBL geese migrated directly from the Klamath Basin to wintering areas in Mexico, bypassing the Central Valley. Ninety percent of the BBL geese wintered in Mexico, as opposed to <20% of the YKD geese. Wetlands of the Interior Highlands in the state of Chihuahua, particularly Laguna Babicora, were used by >90% of the radio-marked geese in Mexico. Marshes along the West Coast comprised the other important wintering habitat in Mexico. The Sacramento Valley of California was the predominant wintering area for YKD geese. BBL geese migrated north from Mexico into the San Joaquin Valley or Sacramento-San Joaquin Delta of California by the last week of January. Fifty-five percent of the BBL population used the Klamath Basin in spring, but many birds staged in eastern Oregon and western Idaho. In contrast, geese from the YKD staged almost exclusively in the Klamath Basin during spring before flying to staging areas in Alaska. Breeding allopatry and temporal partitioning on staging and wintering areas likely has contributed to the evolution of previously described phenotypic differences between these populations. These two populations, along with the Tule Greater White-fronted Goose (A. a. gambeli), may constitute a portion of a Rassenkreis, a group of subspecies connected by clines, each ecotype of which has independent conservation needs.

The Auk↗
USGS1995

Morphological differences in Pacific Coast populations of greater white-fronted geese

We examined morphological relationships of three Pacific coast populations of Greater White-fronted Geese (Anser albifrons). Adult geese were captured and measured at three breeding areas in Alaska and two wintering areas in California, 1980-1991. A two-step discriminant function analysis examined morphological differences among the three populations. Stepwise discriminant function procedures created the simplest measurement models. Each sex was analyzed separately since multivariate analysis of variance indicated that males were significantly larger than females for all three populations. Tule Greater White-fronted Geese (A. a. gambelli) were significantly larger than Pacific Greater White-fronted Geese (A. a. frontalis), hereafter Pacific Geese. The first step of discriminant function analysis created models to differentiate Tule Geese from the Pacific Geese. Bivariate stepwise discriminant function models consisting of only two measurements correctly classified 92% of males (bill height, bill width) and 96% of females (bill height, culmen) of these subspecies. The second step of discriminant function analysis compared a small population of Pacific Geese from the Bristol Bay Lowlands (BBL) of southwestern Alaska with the large population of Pacific Geese that breed on the Yukon-Kuskokwim River Delta (YKD) of westcentral Alaska. We developed models with three (culmen, diagonal tarsus, midtoe) and five (culmen, diagonal tarsus, midtoe, total tarsus, bill height) measurements from stepwise discriminant function analyses to correctly classify 72% of males and 74% of females of these populations. Thus, morphology of Tule Geese differed highly significantly from Pacific Geese, as expected but differences between populations from the BBL and YKD areas were also significant. Morphometric analyses as these provided supporting evidence for clinal variation in populations of Greater White-fronted Geese. They also underscore a need for further studies of differences among North American populations of Greater White-fronted Geese to resolve classification and to allow formulation of subpopulation/subspecies management strategies.

Condor↗
USGS1995

Arctic nesting geese: Alaskan populations

North American populations of most goose species have remained stable or have increased in recent decades (USFWS and Canadian Wildlife Service 1986). Some populations, however, have declined or historically have had small numbers of individuals, and thus are of special concern. Individual populations of geese should be maintained to ensure that they provide aesthetic, recreational, and ecological benefits to the nation. Monitoring and management efforts for geese should focus on individual populations to ensure that genetic diversity is maintain (Anderson et al. 1992). Alaska is the only state with viable breeding populations of arctic geese. Five species (11 subspecies) nest in Alaska, and although these species also breed in arctic regions of Canada or Russia, most geese of the Pacific Flyway originate in Alaska or use Alaskan habitats during migration. Alaskan geese are often hunted for subsistence by Alaskan natives. While data for some areas are lacking, populations of greater white-fronted geese ( Anser albifrons frontalis ) and medium-sized Canada geese ( Branta canadensis ) in interior and northern Alaska appear stable or have increased (King and Derksen 1986). Although only a small number of lesser snow geese ( Chen caerulescens caerulescens ) nest in Alaska, substantial populations occur in Canada and Russia. Populations of Pacific black brant ( B. bernicla nigricans ), emperor geese ( C. canagica ), greater white-fronted geese, and cackling Canada geese ( B.c. minima ) on the Yukon-Kuskokwim Delta (YKD) of western Alaska have declined from their historical numbers and are the focus of special management efforts (USFWS 1989). In addition, populations of tule white-fronted geese ( A.a. gambeli ), Aleutian Canada geese ( B.c. leucopareia ), Vancouver Canada Geese ( B.c. fulva ), and dusky Canada geese ( B.c. occidentalis ) are of special concern because of their limited geographic distributions and small numbers.

Book chapter↗
USGS1994

Classification of vegetation communities in which geese rear broods on the Yukon-Kuskokwim Delta, Alaska

Plant communities are described from an area on the Yukon – Kuskokwim (Y-K) delta of Alaska that is used extensively for brood rearing by three species of geese. Earlier studies identified plant species important as food for young geese, but few studies describe or quantify plant communities. We classified species presence or absence information from over 700 quadrats using a two-way indicator species analysis ( TWINSPAN ) and then tested for agreement of signatures on colour infrared air photos with the identified communities. Sedges were found to dominate all but the wettest and driest communities. Most of the brood-rearing area was covered by Carex ramenskii and Carex rariflora meadows, ponds, Carex mackenziei -dominated pond margins, and C . ramenskii and grass levee meadows. Our interpretation of airphotos accurately predicted vegetation community classes, which will facilitate future studies of habitat selection by geese during the time they are rearing young. The TWINSPAN classification was comparable to classifications of studies conducted elsewhere on the Y-K delta. The interpretation of air photos will enable the identification and evaluation of wetland vegetation complexes and potential goose brood-rearing areas away from our study site.

Alaska↗
USGS1994

Decline in a population of spectacled eiders nesting on the Yukon-Kuskokwim Delta, Alaska

The number of spectacled eiders nesting on two study areas near the Kashunuk River, on the central Yukon-Kuskokwim (Y-K) Delta, Alaska, declined by over 75% in the last 20 years. Nesting densities have remained low, but have not significantly declined since 1985. There has been no decrease in the reproductive effort of individual females as indicated by average clutch sizes. There has been a significant decline in the proportion of nests located on islands on one of the two study areas. Nesting success declined significantly during the 1970's. Success was not monitored in recent years, but has likely been low, based on the poor nesting success and declining numbers of cackling Canada geese and black brant nesting on the area. Nest predation by arctic foxes severely limited the productivity of cackling Canada geese, and foxes were likely the major predators of eider nests. Persistent high predation rates may lead to local extirpation in highly philopatric species such as eiders.

Northwestern Naturalist↗
USGS1994

Genetic diversity in Arctic-nesting geese: Implications for management and conservation

The North Pacific Rim harbors breeding populations of many unique wildlife resources, of which waterfowl are among the most abundant and taxonomically diverse. Arctic nesting geese in particular are wide-spread in distribution (Figure 1), and though only seasons residents, they have evolved many unique adaptations for breeding in northern latitudes. This diversity has been recognized and managed at many taxonomic and geographic levels (Figure 2). Populations are spatially structured on macro- and micro-geographic scales reflecting taxon-specific migratory tendencies, and breeding and winter site fidelity.

Transactions of the North American Wildlife and Na↗
USGS1993

Distribution, abundance, and age ratios of Wrangel Island lesser snow geese Anser caerulescens during autumn migration on the Yukon-Kuskokwim Delta, Alaska

We monitored the distribution, abundance, and productivity of Lesser Snow Geese on the Yukon-Kuskokwim (Y-K) Delta, Alaska during September and October 1991, when the geese were en route from their nesting grounds on Wrangel Island, Russia to wintering areas along the Pacific Coast. Adult geese in brood flocks were captured on Wrangel Island and fitted with either satellite platform transmitting terminal (PTT) transmitters (29 birds) or conventional very high frequency (VHF) radio transmitters (68 birds). All geese with active PTTs used the Y-K Delta. Geese marked with PTTs and VHF transmitters were first detected on the Y-K Delta on 19 and 25 September, respectively, and stayed 8-9 days (range 1 to 25 days) Geese with PTTs used the same areas as unmarked geese and geese with VHF radios, except for the south Delta where only satellite data were obtained. Flocks averaged 1122 birds, and did not vary significantly in size during the study. Population estimates from two independent methods ranged from 58,000 to 88,000 geese during October. Productivity of the Wrangel Island population, as determined from the proportion of young in flocks using the Y-K Delta, has varied from 0.5 to 42.1% with a mean of 29%, since 1975. Age-ratio estimates from the Y-K Delta were highly correlated with, and not significantly different from, those from autumn staging and wintering areas further south, which may indicate that immatures in this population of geese suffer little mortality during the second half of their autumn migration.

Alaska↗
USGS1992

Time allocation by Greater White-fronted Geese: Influence of diet, energy reserves and predation

I determined the amount of time Greater White-fronted Geese ( Anser albifrons frontalis ) allocated to various activities from September to May, 1980-1982 at their primary wintering areas in the Pacific Flyway of North America. The length of time spent on roosts during the day was positively correlated to day length. Geese at roost sites spent the majority of their time sleeping (24-46%), alert (17-40%), walking or swimming (6-24%), and in comfort behaviors (3-25%). The amount of time geese fed each day varied little from early autumn to late spring (4.5-4.9 hr), except during mid-winter when minimum temperatures were below freezing (3.9 hr), and immediately before migration in spring (6.3 hr). The proportion of time devoted to feeding and alert behavior, the two most dominant activities at field sites, varied significantly among seasons and locations. The amount of time geese were actively engaged in foraging each season was more dependent on feeding intensity than the amount of time spent at foraging sites (fields), and varied almost three-fold, from 1.8 hr during late winter to 5.1 hr during late spring. Geese fed in closer proximity to conspecifics, were more frequently disturbed, and spent less time feeding during the hunting season. Exploitation of high energy foods and catabolism of substantial energy reserves probably enabled geese to minimize foraging time during periods of harsh weather and high predation pressure. Seasonal variation in the proportion of time spent feeding corresponded closely to changes in body mass. Greater White-fronted Geese wintering in the Pacific Flyway spent substantially less time feeding than they do in Europe, as geese in California fed primarily on high energy cereal grains, while in Europe they subsist on green vegetation which has relatively less digestible energy than cereal grains.

The Condor↗
USGS1991

Energy dynamics, foraging ecology, and behavior of prenesting greater white-fronted geese

We collected greater white-fronted geese (Anser albifrons frontalis) on their nesting grounds on the Yukon-Kuskokwim Delta, Alaska, when they arrived and again before incubation during 1986 and 1987. Body mass, water content, crude fat, and crude protein increased in female geese between arrival and incubation onset in 1986 and 1987 (P = 0.0001, 0.0002, 0.0329, and 0.0003, respectively). Body mass of male geese during prenesting did not change, but total fat content decreased by about 30%. Crude protein of males was different between years (P = 0.0014). Female geese spent more time feeding than did males (P < 0.001). Primary foods during the prenesting period were pendent grass (Arctophila fulva) shoots and arrowgrass (Triglochin palustris) bulbs. Gizzard contents and orifice staining indicated crowberries (Empetrum nigrum) also were consumed. Of the commonly consumed food items, arrowgrass bulbs had the greatest protein content (21%), and crowberries had the greatest lipid content (10%). Unlike other medium-sized, northern-nesting geese, food (energy) acquired on the nesting grounds by white-fronted geese before incubation increased endogenous reserves necessary for reproduction.

Journal of Wildlife Management↗
USGS1989

Extra-pair copulation in the greater white-fronted goose

Controlled experiments and quantitative field studies with both captive and wild waterfowl (Family Anatidae) have demonstrated that extra-pair copulations (EPCs, both forced and unforced) may be a viable alternative reproductive strategy for males (Mineau and Cooke 1979; Burns et al. 1980; Cheng et al. 1982, 1983; Afron 1985; Evarts and Williams 1987). In a review of EPCs in waterfowl, McKinney et al. (1983) stressed the need for additional information on the extent of such behavior in seemingly monogamous species of birds. Such information would increase our understanding of the extent of mixed reproductive strategies as formally hypothesized by Trivers (1972). Extra-pair copulations have been reported for only three of 22 (14%) species of geese and swans (Tribe Anserini), but are known to occur in 37 of 122 (30%) of the remaining species of waterfowl (McKinney et al. 1983, 1984; Welsh 1988). Socioecological differences between Anserini and most other anatids may provide insight into the evolution of extra-pair copulatory behavior, as male Anserini (unlike most other Anatidae) provide extensive parental care and maintain long-term pair bonds (Owen 1980, p. 76). Cuckolded male Anserini thus stand to lose more in the form of reproductive investment than other male anatids, which may invest less in a given clutch and generally have short-term pair bonds. I describe here an observation of extra-pair copulation in wild Greater White-fronted Geese (A nser albifrons frontalis ). The observation is significant not only because it augments our meager documentation of this behavior within the Anserini, but it is the first observation of such behavior in a noncolonial goose (Mineau and Cooke 1979, McKinney et al. 1983). The occurrence of EPC behavior in a dispersal-nesting goose is important, as proximity to potential mates has been hypothesized as a factor possibly selecting for EPC behavior in geese (McKinney et al. 1983) and other species of monogamous birds (Gladstone 1979, but see Westneat 1987).

Alaska↗
USGS1987

An inexpensive device for recording animal behavior

Recording animal behavior is tedious and time consuming when behaviors are recorded on tape and transcribed to data sheets. Data loggers circumvent these problems, but can be prohibitively expensive and may require extensive programming (see Hensler et al. [1986]). I describe an inexpensive, efficient alternative for recording behavioral observations.

Wildlife Society Bulletin↗
USGS1984

Breeding biology of Pacific white-fronted geese

Nesting ecology of Pacific white-fronted geese ( Anser albifrons frontalis ) was studied on a 9.9-km 2 area on the Yukon-Kuskokwim (Y-K) Delta, Alaska, during 1977-79. Availability of nesting habitat varied considerably among years because of differences in time of snow- and icemelt. Mean clutch size was 3.7 eggs in the late spring thaw year and 5.2 and 5.7 eggs in early snowmelt years. Peak (and duration) of nest initiation was 1-2 June (16 days) in the late spring and 15-18 May (20-21 days) during early springs. When nest sites were available early, the time interval between arrival and date of nest initiation closely approximated the time required for rapid yolk development. This suggests that whitefronts may be physiologically prevented from nesting earlier in such years. The duration of nest initiation was comparable to that of other goose species nesting on the Y-K Delta, but longer than for goose populations of several species nesting farther north or in the midcontinent. Overall, 68% of whitefront nests were in lowland habitat, 23% in intermediate habitat, and 10% in upland habitat, but habitat use varied significantly between early and late years. Whitefronts most commonly nested on slough banks (55%), lake shores (23%), and grass-sedge meadows (11%). A quantitative description of vegetation associated with nest sites is given. Major causes of nest destruction were flooding (28%) and predation (9%). Nesting success over the 3-year period averaged 62%.

Alaska↗