Geology topics

Paul L. Flint

Publications and source records attributed to Paul L. Flint.

At least 109 records · Page 6Linked to original sources

USGS1998

A drift experiment to assess the influence of wind on recovery of oiled seabirds on St Paul Island, Alaska

We used wooden blocks to estimate the proportion of oiled seabird carcasses that were likely to be recovered on beaches of St Paul Island, Alaska following a near-shore oil spill. We released a total of 302 blocks 6 km north of the island in 1997 at the site of a 17 II 1996 oil spill. We used a paired design and released half the blocks when the winds were onshore and released the second half when the winds were offshore. We systematically searched beaches after the second release to recover blocks. We recovered 93 of 152 (61%) blocks released when winds were onshore but only 1 of 150 (0.7%) blocks released when winds were offshore. Given that winds following the 1996 spill were offshore, we conclude that most birds killed at sea following the 1996 spill were likely not recovered on beaches.

Marine Pollution Bulletin↗

USGS1998

Blood lead concentrations of spectacled eiders near the Kashunuk River, Yukon Delta National Wildlife Refuge, Alaska

We collected, 342 blood samples from spectacled eiders ( Somateria fischeri ) on their breeding grounds in western Alaska from late May through to early August 1993–1995. Lead concentrations of ≥0.50 p.p.m. wet weight were found in the blood of 20% of the adult female eiders, 2% of the adult males and 6% of the ducklings. Lead was detected (≥0.02 p.p.m.) more frequently in the blood of adult females than in adult males or ducklings and the maximum concentrations were 14.37, 0.50 and 4.28 p.p.m. wet weight, respectively. In adult females, there was a significant difference in the proportion of detectable blood lead concentrations between three collection times (arrival/nesting, hatch and brood rearing), with the highest proportion (92%) occurring at hatch. Nine hens with blood lead concentrations of ≥0.50 p.p.m. were captured a second time several weeks to 1 year later. In the hens sampled twice at intervals of several weeks, the blood lead concentrations increased and declined at mean daily rates of 1.10 and 0.94, respectively. The lead concentrations in the blood of adults were not correlated with body weights. Radiographs were taken of 119 eiders and corresponding blood samples from 98 of these birds were analysed for lead. Ingested shot was seen in X-rays of 12 adults and three ducklings and, of the 13 blood samples tested, all had detectable lead concentrations. Of the birds without radiographic evidence of ingested shot, 84% of the adult females, 19% of the adult males and 17% of the ducklings had detectable lead concentrations in their blood. Breeding ground exposure of waterfowl to lead shot is unusual and is of particular concern in spectacled eiders because of their threatened status and declining numbers in western Alaska.

Alaska↗

USGS1998

Effect of lead poisoning on spectacled eider survival rates

Spectacled eider ( Somateria fischeri ) populations on the Yukon-Kuskokwim Delta (Y-K Delta), Alaska, declined rapidly through the 1980s, and low adult female survival was suggested as the likely cause of the decline. We used mark-resighting techniques to study annual survival rates of adult female spectacled eiders at 2 sites on the Y-K Delta during 1993-96. Our data suggest survival rates may differ among sites. However, a model fit to a subset of data on females for which we knew lead levels in blood suggests lead exposure influences survival. Adult females exposed to lead prior to hatching their eggs survived at a much lower rate (0.44 ?? 0.10) each year than females not exposed to lead before hatch (0.78 ?? 0.05). We suggest most mortality from lead exposure occurs over winter, and the related reduction in adult survival may be impeding recovery of local populations. We encourage managers to curtail input of lead shot into the environment.

Alaska↗

USGS1998

A model of northern pintail productivity and population growth rate

Our objective was to synthesize individual components of reproductive ecology into a single estimate of productivity and to assess the relative effects of survival and productivity on population dynamics. We used information on nesting ecology, renesting potential, and duckling survival of northern pintails ( Anas acuta ) collected on the Yukon-Kuskokwim Delta (Y-K Delta), Alaska, 1991-95, to model the number of ducklings produced under a range of nest success and duckling survival probabilities. Using average values of 25% nest success, 11% duckling survival, and 56% renesting probability from our study population, we calculated that all young in our population were produced by 13% of the breeding females, and that early-nesting females produced more young than later-nesting females. Further, we calculated, on average, that each female produced only 0.16 young females/nesting season. We combined these results with estimates of first-year and adult survival to examine the growth rate (X) of the population and the relative contributions of these demographic parameters to that growth rate. Contrary to aerial survey data, the population projection model suggests our study population is declining rapidly (X = 0.6969). The relative effects on population growth rate were 0.1175 for reproductive success, 0.1175 for first-year survival, and 0.8825 for adult survival. Adult survival had the greatest influence on X for our population, and this conclusion was robust over a range of survival and productivity estimates. Given published estimates of annual survival for adult females (61%), our model suggested nest success and duckling survival need to increase to approximately 40% to achieve population stability. We discuss reasons for the apparent discrepancy in population trends between our model and aerial surveys in terms of bias in productivity and survival estimates.

Alaska↗

USGS1998

Observations of geese foraging for clam shells during spring on the Yukon-Kuskokwim Delta, Alaska

We studied the behavior of geese on exposed river ice during spring on the Yukon-Kuskokwim Delta. The predominant behavior while on the ice for both sexes was foraging; however, females foraged more than males. Visual inspection of the ice revealed no potential plant or animal food items. However, numerous small (<20 mm) clam shells ( Macoma balthica ) and pieces of shell were noted. It appeared that geese were foraging on empty clam shells. This potential source of calcium was available to breeding geese just prior to egg formation and geese likely stored this calcium in the form of medullary bone for use during egg formation.

Alaska↗

USGS1997

Persistence rates and detection probabilities of oiled king eider carcasses on St Paul Island, Alaska

Following an oil spill off St Paul Island, Alaska in February 1996, persistence rates and detection probabilities of oiled king eider (Somateria spectabilis) carcasses were estimated using the Cormack-Jolly-Seber model. Carcass persistence rates varied by day, beach type and sex, while detection probabilities varied by day and beach type. Scavenging, wave action and weather influenced carcass persistence. The patterns of persistence differed on rock and sand beaches and female carcasses had a different persistence function than males. Weather, primarily snow storms, and degree of carcass scavenging, diminished carcass detectability. Detection probabilities on rock beaches were lower and more variable than on sand beaches. The combination of persistence rates and detection probabilities can be used to improve techniques of estimating total mortality.

Marine Pollution Bulletin↗

USGS1997

Productivity of nesting spectacled eiders on the lower Kashunuk River, Alaska

We studied the chronology and success of nesting Spectacled Eiders ( Somateria fischeri ) along the lower Kashunuk River on the Yukon-Kuskokwim Delta from 1991-1995. Nest initiation dates ranged from 16 May-22 June. Median nest initiation dates were correlated with the break-up of ice on the Kashunuk River. Clutch sizes declined seasonally, and mean clutch size varied among years ranging from 4.8-5.6 eggs. The frequency of nests containing inviable eggs (24% of successful nests, x = 0.6 unhatched eggs per successful nest) did not differ among years or nest initiation dates, and may be related to exposure to contaminants. The rate of partial depredation also did not vary among years or initiation dates (23% of nests, x = 0.5 eggs taken/successful nest). We detected no effect of marking or visitation on daily survival rate of nests. Nests initiated early in the year were more successful than late nests; thus, early nesting females laid larger clutches and were more likely to nest successfully than late nesters. Nest success varied among years and declined from 73% in 1991 to 18% in 1994. Nest success increased to 76% in 1995 when we reduced the Mew Gull ( Larus canus ) population on the study area. While inviability and partial depredation averaged over 1 egg per successful nest, the production lost in nests that were abandoned or completely destroyed by predators was much greater. Our data indicate that Spectacled Eiders nesting on our study area experience relatively high production; however, without information regarding annual survival and recruitment. it is not possible to draw conclusions about population growth rates.

Condor↗

USGS1997

Habitat use by nesting and brood rearing northern pintails on the Yukon-Kuskokwim Delta, Alaska

We studied habitat use by nesting and brood-rearing northern pintails ( Anas acuta ) on the coastal Yukon-Kuskokwim (Y-K) Delta, 1991-93. We used a digital habitat map constructed from color infrared aerial photos to assign habitat types to nest and brood locations and estimate habitat availability. Sixty-nine percent of females nested on slough banks in highly saline, tidally influenced habitats where we observed few mammalian predators. Nesting pintails likely preferred slough banks because they were higher and well drained early in the nesting season. Radiomarked females selected moderately saline habitats that were only occasionally or rarely influenced by tides for brood rearing. Eighty percent of females that nested in saline habitats moved their broods to less saline habitats, and those that nested in preferred brood-rearing habitats never moved to more saline habitats to rear their broods. Managers should be aware that in coastal wetlands the proximity of good-quality nesting and brood rearing habitats is important, and the distribution of nesting pintails may not reflect the distribution of broods and vice versa.

Alaska↗

USGS1997

Survival of spectacled eider adult females and ducklings during brood rearing

We studied survival of adult female and duckling spectacled eiders ( Somateria fischeri ) during brood rearing on the Yukon-Kuskokwim Delta, Alaska from 1993 to 1995. Duckling survival to 30 days of age averaged 34% with a 95% confidence interval from 25 to 47%. Half (49%) of radiomarked adult females had lost all their ducklings by 30 days after hatch. Most (74%) duckling mortality occurred in the first 10 days. Adult female survival during the first 30 days of brood rearing was 93 ± 3% (SE). Females died from lead poisoning, as a result of ingesting lead shot, and predation. Mortality of adult females during brood rearing is probably higher than during other times of the year. Low adult female survival during the breeding season may be contributing to the overall population decline of spectacled eiders.

Alaska↗

USGS1996

Survival of northern pintail ducklings on the Yukon-Kuskokwim Delta, Alaska

We studied survival rates of Northern Pintail ( Anas acuta ; hereafter pintail) broods and ducklings along the lower Kashunuk River on the Yukon-Kuskokwim Delta, Alaska. Survival rates were determined for 770 ducklings in 111 broods. Brood sizes at hatch were smaller in 1993 versus 1991 and 1992. Duckling survival rates were lower than those reported in previous studies and differed among years. Survival rates of ducklings declined with hatching date at a rate of 0.6% per day. Most mortality occurred during the first 10 days after hatch. Duckling survival rates were correlated with reported annual and seasonal variation in nesting success. This covariation probably results in large geographic and annual fluctuations in pintail production on the Yukon-Kuskokwim Delta. Early nesting pintails had better nesting success and duckling survival, which may offset higher nutritional costs of early nesting through higher recruitment.

Alaska↗

USGS1996

Variation in egg size of the northern pintail

Egg size is an important determinant of reproductive investment by birds. For many species, total investment in a clutch is limited by the size of stored reserves (Ankney and MacInnes 1978, Esler and Grand 1994a). Egg size determines the unit by which these stored reserves are partitioned. Individual females in most species of waterfowl show a high repeatability for egg size, implying that individual either cannot, or do not, alter their egg size in response to varying environmental conditions (batt and Prince 1979, Duncan 1987, Laurila and Hario 1988, Lessells et al 1989, Flint and Sedinger 1992). Thus differences in egg size appear to represent different reproductive strategies among individuals. Fitness can be measured by the number of offspring an individual contributes to a population. Egg size may be related to fitness in some species fo waterfowl as young from larger eggs are better able to survive extreme conditions (Ankney 1980, Thomas and Brown 1988). Birds laying larger clutches are almost always more fit as they fledge more young (Lessells 1986, Rockwell et al 1987, Flint 1993). These fitness patterns create the potential for a trade-off between clutch size and egg size where females laying large clutches of small eggs have the same fitness as females laying smaller clutches of large eggs. The fact that Northern Pintails ( Anas acuta ) utilize stored reserves (Mann and Sedinger 1993, esler and Grand 1994a) and have a high repeatability for egg size (i.e. egg size is fixed) (Duncan 1987), makes them candidates to engage in clutch size=egg size trade-offs (Rowher 1988, Rowher and Eisenhauer 1989). An inverse relationship between egg size and clutch size would be indicative of a phenotypic trade-off among these fitness components. Our goal in this study was to describe egg size variation in Northern Pintails (hereafter pintails) with regard to female age, body size, clutch size, year, initiation date, and nesting attempt. We compare our results to those from other populations of nesting pintails and discuss whether phenotypic clutch size-egg size tradeoffs exist for pintails.

Alaska↗

USGS1996

Allocation of limited reserves to a clutch: A model explaining the lack of a relationship between clutch size and egg size

Lack (1967, 1968) proposed that clutch size in waterfowl is limited by the nutrients available to females when producing eggs. He suggested that if nutrients available for clutch formation are limited, then species producing small eggs would, on average, lay more eggs than species with large eggs. Rohwer (1988) argues that this model should also apply within species. Thus, the nutrition-limitation hypothesis predicts a tradeoff among females between clutch size and egg size (Rohwer 1988). Field studies of single species consistently have failed to detect a negative relationship between clutch size and egg size (Rohwer 1988, Lessells et al. 1992, Rohwer and Eisenhauer 1989, Flint and Sedinger 1992, Flint and Grand 1996). The absence of such a relationship within species has been regarded as evidence against the hypothesis that nutrient availability limits clutch size (Rohwer 1988, 1991, 1992; Rohwer and Eisenhauer 1989).

The Auk↗

USGS1995

Variation in brood behavior of Black Brant

We studied behavior of broods of Black Brant ( Branta bernicla nigricans ) during five summers between 1987 and 1993, a period in which the local breeding population increased >3-fold. Goslings spent more time foraging than adults of either sex, while adult males spent more time alert and less time foraging than adult females. Percentage of time spent alert was positively correlated with brood size for adult males but not adult females. Foraging time for all age and sex classes increased with date following hatch within years. Foraging time increased and time spent alert decreased between 1987 and 1993 for both adult males and adult females. The trend in foraging behavior for adults is consistent with an hypothesis of declining food availability at higher brood densities and declining alert behavior by adults has implications for prefledging survival of young.

Alaska↗

USGS1995

Environmental influence on life-history traits: Growth, survival, and fecundity in Black Brant ( Branta bernicla )

We studied relationships between body size of female Black Brant goslings ( Branta bernicla nigricans ) late in their growth period and first year survival, eventual adult body size, breeding propensity, and size and volume of clutches they eventually produced to examine the relationship between growth and fitness in this population. We indexed body size by calculating PC1 scores based on either culmen and tarsus, or culmen, tarsus, and mass. Gosling (PC scores based on culmen and tarsus) size was positively correlated with resighting rate (P = 0.005), indicating that larger goslings survived at a higher rate than did smaller goslings. Gosling size was correlated with adult size of the same individuals (P = 0.0004). Larger goslings were more likely to breed as 2- or 3-yr-olds than were medium or small goslings (P = 0.008). Larger adult brant laid more eggs (P = 0.03) and produced clutches with greater total volume (P = 0.03) than did smaller brant. Given the important role of foraging environment in growth of goslings, these data suggest an important role of early environment in determining life-history traits.

Alaska↗

USGS1995

Survival of juvenile black brant during brood rearing

Survival of young is an important and poorly understood component of waterfowl productivity. We estimated survival of black brant ( Branta bernicla nigricans ) goslings during summers 1987-89 on the Yukon-Kuskokwim Delta, Alaska, to determine timing and magnitude of gosling mortality and to compare methods of estimating gosling survival. Eighty-two percent of radio-tagged adult females (n = 61) fledged ≥1 gosling (brood success). We estimated survival of goslings within broods by 3 methods: (1) changes in mean brood size through time, (2) observation of goslings associated with marked adults, and (3) age ratios of brant captured in banding drives. Estimates of gosling survival within successful broods averaged 81% and ranged from 66 to 92%. Combining brood success and gosling survival within successful broods yielded estimates of overall gosling survival that averaged 68%, ranging from 79% in 1987 to 56% in 1989. Eighty-two percent of gosling mortality occurred in the first 15 days. Estimates of survival on the basis of age ratios of birds captured in banding drives are biased low. Our estimates of average gosling survival are higher than reported for other species of geese.

Alaska↗

USGS1995

Effects of harness-attached transmitters on premigration and reproduction of Brant

Radio transmitters are an important tool in waterfowl ecology studies, but little is known about their effects on free-ranging geese. We attached transmitters to female brant ( Branta bernicla nigricans ) to investigate migration schedules at a fall staging area, return rates to nesting grounds, and nesting rates of returning females in subsequent breeding seasons. Radio-tagged females (n = 62) carried either 35-g back-mounted transmitters attached with ribbon harnesses, or 26- or 32-g back-mounted transmitters affixed with plastic-coated wire harnesses (Dwyer 1972). Arrival and departure schedules at Izembek Lagoon, Alaska, did not differ (P > 0.05) between radio-tagged females and the entire population in 1987-89. Color-banded females with transmitters returned to the breeding colony in subsequent nesting seasons (1988-92) at a lower (P ≤ 0.003) rate (≤4%) than color-banded females without transmitters (57-83%). The 1 returning color-banded female with a transmitter did not breed, while an average 90% of the returning color-banded females without transmitters nested in subsequent breeding seasons (P = 0.005). Back-mounted, harness-attached transmitters may bias data in studies of waterfowl behavior, productivity, and survival.

Alaska↗

USGS1995

A device for simultaneously measuring nest attendance and nest temperature in waterfowl

Previous studies of waterfowl have measured nest attendance and nest temperature separately using a variety of methods. A device was developed that monitors nest attendance and temperature simultaneously. The device consists of an artificial egg with a microswitch that records nest attendance and a thermistor probe that records temperature. Data are stored in a single-channel data logger. The device described measures the length of incubation breaks, and nest cooling and warming rates.

Journal of Field Ornithology↗

USGS1991

Growth rate is negatively correlated with hatch date in Black Brant

Arctic geese nest in a highly seasonal environment in which ungrazed plants reach peak nitrogen concentrations when goslings hatch (Sedinger and Raveling 1986). Grazing by geese prolongs peak nutrient concentrations but reduces food availability. This should cause nutrient availability to decline seasonally. Here, we test the hypothesis that late-hatching goslings of Black Brant ( Branta bernicla nigricans ) grow more slowly than those hatching early. We substracted the sizes of wild goslings from those of captive-reared goslings of the same age and regressed the differences against hatch date. Differences between wild- and captive-reared goslings for body mass, tarsus length, and culmen length were significantly negatively related to hatch date; i.e., late-hatching wild goslings were smaller than those hatching early, after accounting for age. We detected no between-year difference in gosling size, but male goslings were larger than females of the same age for all measures. Egg size was only weakly associated with size of goslings 1 mo after hatching, but we detected no effect of other brood characteristics on growth. Seasonal variation in gosling growth rate may favor early nesting in arctic geese.

Alaska↗