Geology topics

Susan M. Haig

Publications and source records attributed to Susan M. Haig.

86 records · Page 5Linked to original sources

USGS2002

Regional fidelity and movement patterns of wintering killdeer in an agricultural landscape

Killdeer ( Charadrius vociferus ) is a common and widespread North American species for which there are few studies of residency patterns and movements. We quantified fidelity and movement patterns of 24 radio-tagged Killdeer in the Willamette Valley of Oregon during the winter of 1999-2000. Results from telemetry surveys and census efforts revealed that the group monitored was composed of winter residents (63%), winter transients (26%), and year-round residents (11%). Movements were localized with birds detected at an average distance of 5.15 ± 0.91 (SE) km from the site of capture. Mean home range size (95% kernel) was 7.73 ± 3.19 km 2 . However, results also indicated periodic exploratory movements, with some birds detected up to 30 km from marking sites. Overall, individuals exhibited a low degree of fidelity to specific sites and were detected at an average of 11.9 ± 1.1 sites. No differences were found in monthly movement patterns. In almost all cases, year-round residents were more sedentary than winter residents and winter transients. Results indicate a complex regional population structure and highlight the need to consider both migrant and resident birds, as well as seasonal differences in habitat needs and space use requirements, in future conservation planning efforts.

Oregon↗

USGS2001

Geographic variation and genetic structure in Spotted Owls

We examined genetic variation, population structure, and definition of conservation units in Spotted Owls ( Strix occidentalis ). Spotted Owls are mostly non-migratory, long-lived, socially monogamous birds that have decreased population viability due to their occupation of highly-fragmented late successional forests in western North America. To investigate potential effects of habitat fragmentation on population structure, we used random amplified polymorphic DNA (RAPD) to examine genetic variation hierarchically among local breeding areas , subregional groups , regional groups , and subspecies via sampling of 21 breeding areas (276individuals) among the three subspecies of Spotted Owls. Data from 11 variable bands suggest a significant relationship between geographic distance among local breeding groups and genetic distance (Mantel r = 0.53, P < 0.02) although multi-dimensional scaling of three significant axes did not identify significant grouping at any hierarchical level. Similarly, neighbor-joining clustering of Manhattan distances indicated geographic structure at all levels and identified Mexican Spotted Owls as a distinct clade. RAPD analyses did not clearly differentiate Northern Spotted Owls from California Spotted Owls. Among Northern Spotted Owls, estimates of population differentiation (F ST ) ranged from 0.27 among breeding areas to 0.11 among regions. Concordantly, within-group agreement values estimated via multi-response permutation procedures of Jaccard's distances ranged from0.22 among local sites to 0.11 among regions. Pairwise comparisons of F ST and geographic distance within regions suggested only the Klamath region was in equilibrium with respect to gene flow and genetic drift. Merging nuclear data with recent mitochondrial data provides support for designation of an Evolutionary Significant Unit for Mexican Spotted Owls and two overlapping Management Units for Northern and California Spotted Owls.

Conservation Genetics↗

USGS2001

Killdeer population trends in North America

Killdeers (Charadrius vociferus) are considered a common species that inhabits a wide range of wetland and upland habitats throughout much of North America, yet recent information suggests that they may be declining regionally, if not throughout much of their range. To address this issue, we examined population trends of this species at multiple spatial and temporal scales using data from two major avian survey efforts, the Breeding Bird Survey (BBS) and Christmas Bird Count (CBC). A summary of BBS trends indicates significant long-term (1966a??1996) declines in breeding populations across North America. Geographic regions driving this decline were Canada, western survey regions of the continent, and select southeastern states. In contrast, over the same time period, Killdeer populations increased in some midwestern states, particularly those in the Great Lakes region. Recent BBS trends (1986a??1996) indicate highly significant declines across most areas of North America surveyed. Trends from CBC data (1959a??1988) indicate declines at a smaller spatial scale. While the ability of current major avian survey efforts to detect population trends for Killdeer and other shorebird species warrants further examination, significant negative trends in Killdeer populations indicates the need to further investigate the status of this species.

Journal of Field Ornithology↗

USGS2001

Winter distributions of North American Plovers in the Laguna Madre regions of Tamaulipas, Mexico and Texas, USA

To determine the distribution and abundance of wintering plovers in the Laguna Madre of Texas and Tamaulipas, surveys were conducted in December 1997 and February 1998, along a 160 km stretch of barrier islands in Mexico and- 40 km of shoreline on South Padre Island, Texas. Altogether, 5,673 individuals, representing six plover species, were recorded during the surveys. Black-bellied Plovers Pluvialis squatarola were the most numerous (3 ,013 individuals) representing 53% of the total number of plovers observed. Numbers of Piping Charadriusm elodu, Snowy C . alexandrinus, Semipalmated C. semipalmatus and Wilson's Plovers C. wilsonia were 739, 1,345, 561, and 13 birds, respectively. Most individuals (97%) of all species except Wilson's Plovers were observed on bayside flats of the barrier islands. Similar numbers of Piping Plovers were recorded at South Padre Island, Texas, and in the Laguna Madre de Tamaulipas. Over 85% of the individuals of each of the other species were found in the more extensively surveyed Mexico portion of Laguna Madre. In Tamaulipas, most plover species were observed more often on algal flats than any other substrate. These results provide evidence of the value of these systems as wintering areas for plover species and indicate the need for more extensive survey efforts to determine temporal and spatial variation in the distribution of these species within the Laguna ecosystem.

Wader Study Group Bulletin↗

USGS2000

Viability of piping plover Charadrius melodus metapopulations

The metapopulation viability analysis package, VORTEX , was used to examine viability and recovery objectives for piping plovers Charadrius melodus , an endangered shorebird that breeds in three distinct regions of North America. Baseline models indicate that while Atlantic Coast populations, under current management practices, are at little risk of near-term extinction, Great Plains and Great Lakes populations require 36% higher mean fecundity for a significant probability of persisting for the next 100 years. Metapopulation structure (i.e. the delineation of populations within the metapopulation) and interpopulation dispersal rates had varying effects on model results; however, spatially-structured metapopulations exhibited lower viability than that reported for single-population models. The models were most sensitive to variation in survivorship; hence, additional mortality data will improve their accuracy. With this information, such models become useful tools in identifying successful management objectives; and sensitivity analyses, even in the absence of some data, may indicate which options are likely to be most effective. Metapopulation viability models are best suited for developing conservation strategies for achieving recovery objectives based on maintaining an externally derived, target population size and structure.

Biological Conservation↗

USGS2000

Status of a broadly distributed endangered species: Results and implications of the second International Piping Plover Census

Methods for monitoring progress toward recovery goals are highly variable and may be problematic for endangered species that are mobile and widely distributed. Recovery objectives for Piping Plovers ( Charadrius melodus ) include attainment of minimum population sizes within specified recovery units, as determined by two U.S. and two Canadian recovery teams. To assess progress toward these goals, complete surveys of the species' winter and breeding ranges in Canada, the United States, Mexico, the Bahamas, and the Greater Antilles are conducted every 5 years. In 1996, 1200 biologists and volunteers participated in the second International Piping Plover Census, tallying 2515 wintering birds and 5913 adults (2668 breeding pairs) during the breeding census. Winter numbers were 27% lower than those of the first international census conducted in 1991, with substantially fewer wintering birds along the Gulf of Mexico and an overall increase in numbers along the Atlantic Coast. Large numbers of wintering plovers remain undetected. In 1996, the total number of breeding adults was 7.7% higher than in 1991. Regionally, breeding numbers were 31% higher along the Atlantic Coast and 20% higher in the small Great Lakes population, but declined by 5% in the U.S. Great Plains and the Canadian Prairie. Target recovery numbers were met only for Saskatchewan but were approached in Alberta and New England. The results suggest that Piping Plover distribution and habitat use in the U.S. Great Plains/Canadian Prairie region may shift dramatically with water conditions.

Greater Antilles↗

USGS2000

Postbreeding movements of American Avocets and implications for wetland connectivity in the western Great Basin

Wetlands in the western Great Basin of the United States are patchily distributed and undergo extensive seasonal and annual variation in water levels. The American Avocet ( Recurvirostra americana ) is one of many shorebird species that use these wetlands as breeding and migratory stopover sites and must adjust to variable conditions. We used radio telemetry to determine postbreeding, premigratory movement patterns of avocets throughout the region. In 1996 and 1997, 185 breeding adults were captured and fitted with radio transmitters at five breeding areas in Oregon, California, and Nevada. Regular aerial and ground surveys were conducted at the five main study areas from June through September, or until all avocets had left a site. Other wetlands in the western Great Basin also were surveyed by aircraft for the presence of radio-marked birds. Fifty-six percent of radio-marked avocets were still detected in the region at least eight weeks after capture. Each of these individuals was detected at an average of 2.1 lakes (range 0 to 6), with 74% found at more than one lake system. Forty radio-marked individuals moved at least 200 km between wetlands prior to migration, most of which dispersed northward. Male and female patterns did not differ significantly. Overall, movements may be associated with a prebasic molt, exploitation of a superabundant food source in northern lakes, and reconnaissance for future breeding efforts or staging sites. These results also demonstrate wide-ranging patterns of dispersal in this species and suggest a need for the consideration of large-scale habitat connectivity issues in establishing conservation strategies for shorebirds in the western Great Basin.

The Auk↗

USGS2000

Space use of killdeer at a Great Basin breeding area

Wetland conservation efforts require knowledge of space use by a diversity of waterbirds. However, determining space use of animals requires intensive monitoring of individual organisms. Often, activity patterns during much of the annual cycle are neglected in analyses of home range and habitat use. From 1995-97, we monitored space use in a population of individually marked killdeer ( Charadrius vociferus ) that breed, and reside for a number of additional months each year, in the western Great Basin. We used linear distance measures and home range-area estimates, derived by fixed-kernel methods, to examine patterns of space use of adults prior to, during, and following nesting. Overall, killdeer used a local area of approximately 6 ha. Birds remained closer to nests while tending eggs than either before or after nesting, although extensive movements away from the nest were observed during all time periods. Females tended to move farther from nests than did males. Birds nesting farther from water bodies were generally observed at greater distances from nests than those nesting closer to shorelines during all time periods. Twenty-seven percent of individuals were observed greater than 1 km from nest locations, particularly during postnesting periods. During nesting periods, males were less likely to be observed at longer distances from nests than were females. There were no differences in home range size based upon sex, time period, or distance from water. We suggest that home range size may not always accurately measure differences in space use and that multiple measures, including distance from nests, should be considered. Understanding the sedentary nature of killdeer during much of the annual cycle and their intense use of local areas is important for making management decisions. Coupled with data on other shorebird species, this information also has broader implications for management of wetland systems by indicating large scale spatial and habitat requirements and the connectivity of geographically distinct habitat patches.

California, Idaho, Nevada, Oregon, Washington↗

USGS2000

Application of a modified harness design for attachment of radio transmitters to shorebirds

Radio transmitter attachment methodology is important to the design of radio telemetry studies. In 1998, we attached 5 transmitters to a captive population of Western Sandpipers ( Calidris mauri ) and 7 transmitters to wild Killdeer ( Charadriusv ociferus ) using a modified version of the Rappole and Tipton (1991) figure-8 leg-loop harness. Captive birds fitted with harnesses did not exhibit quantifiable differences in behavior relative to control birds. Based on initial success in using the leg-loop harnesses, we used harnesses to attach transmitters in the wild to 30 Killdeer and 49 Dunlin ( Calidris alpina ) during the winters of 1998-1999 and 1999-2000. This was part of a study on movements of wintering shorebirds in the Willamette Valley of Oregon, USA. Wild birds showed no adverse effects of the harnesses.Thus, the described harness is a practical method for attachment of transmitters to shorebirds. Advantages of this harness method include a reduction in handling time at capture, elimination of the need to clip feathers for attachment, and increased transmitter retention time.

Oregon↗

USGS1998

Molecular contributions to conservation

Recent advances in molecular technology have opened a new chapter in species conservation efforts, as well as population biology. DNA sequencing, MHC (major histocompatibility complex), minisatellite, microsatellite, and RAPD (random amplified polymorphic DNA) procedures allow for identification of parentage, more distant relatives, founders to new populations, unidentified individuals, population structure, effective population size, population-specific markers, etc. PCR (polymerase chain reaction) amplification of mitochondrial DNA, nuclear DNA, ribosomal DNA, chloroplast DNA, and other systems provide for more sophisticated analyses of metapopulation structure, hybridization events, and delineation of species, subspecies, and races, all of which aid in setting species recovery priorities. Each technique can be powerful in its own right but is most credible when used in conjunction with other molecular techniques and, most importantly, with ecological and demographic data collected from the field. Surprisingly few taxa of concern have been assayed with any molecular technique. Thus, rather than showcasing exhaustive details from a few well-known examples, this paper attempts to present a broad range of cases in which molecular techniques have been used to provide insight into conservation efforts.

Ecology↗

USGS1998

Wetland connectivity and waterbird conservation in the western Great Basin of the United States: Introduction to workshop

As scientists, managers and landowners, we have come to realize that to best understand the local and regional value of individual wetlands, we need to take a broad geographic, taxonomic, and management view. In December 1994, a symposium was held in Reno, Nevada that addressed this topic for shorebirds by bringing together researchers and managers from the Western Great Basin to discuss shorebird research and management in the region (Reed et al. 1997, International Wader Studies 9). In February 1998, a similar, but broader, symposium was held in Bend, Oregon that addressed wetland connectivity and waterbird conservation in the Western Great Basin. Over 100 participants spent one day listening to talks from waterbird researchers that focused on multi-scale habitat use and movements of birds in the region. From American Avocets Recurvirostra americana to White Pelicans Pelcanus erythrorhynchos we learned of phenomenal intra-season movements throughout the Basin and the value of collecting detailed data of this nature for representative waterbirds. We learned also about the National Shorebird Conservation Plan and spent the next day in discussion groups where future research and management priorities were outlined. These discussions were the first regional planning effort for the National Plan.

Great Basin↗

USGS1997

Shorebird-prey interactions in South Carolina coastal soft-sediments

We investigated the simultaneous influence of benthic prey (primarily insect larvae, oligochaetes, and polychaetes) on spring-migrating shorebirds (Charadriiformes) and shorebirds on prey in brackish managed wetlands of South Carolina. We proposed that positive correlations between shorebird and prey densities and between prey reduction and shorebird density might result in a negative feedback loop. The loop would be characterized by shorebird redistribution over time and equalization of shorebird and prey densities (and biomass) across the site. In support of the feedback loop ( i ) there were positive correlations between shorebird and prey densities (and biomass) early in migration; ( ii ) shorebird predation was responsible for declines of 49% in prey density and 50% in prey biomass in a shorebird exclosure experiment, with shorebird density positively correlated with prey decline in open plots; ( iii ) there was equalization of prey biomass across the site, and relative prey species abundance appeared to become more equal. Contrary to predictions, shorebirds did not redistribute after prey reduction, and patchiness of shorebird and prey densities persisted across the site. This failure was attributed to high prey density, even at the season's end, and high water depths. There were no confounding indirect trophic-level effects.

South Carolina↗

USGS1997

Shorebird diet and size selection of nereid polychaetes in South Carolina coastal diked wetlands

Coastal wetlands that are diked and managed may supplement declining natural habitat for migrating shorebirds (Charadriiformes). However, data on shorebird diet in these diked wetlands are scarce. We examined shorebird diet and prey size selection in brackish diked wetlands at the Yawkey Center on South Island, South Carolina, USA. Gut contents of seven Lesser Yellowlegs (Tringa flavipes) and seven Short-billed Dowitchers (Limnodromus griseus) were examined. The most common items in gut contents were mandibles of the nereid polychaete, Laeonereis culveri, followed by insects. L. culveri eaten by Short-billed Dowitchers were significantly larger than those eaten by Lesser Yellowlegs. This difference may be related to differences in bill length and feeding tactics. We make suggestions on how to maintain high numbers of L. culveri in diked wetlands, but more research on the timing of colonization by invertebrates is needed in shorebird conservation efforts.

Journal of Field Ornithology↗

USGS1996

Shorebird use of South Carolina managed and natural coastal wetlands

While many migrating and wintering shorebird (Charadriiformes) species face declines in quality and quantity of natural stopover sites, diked wetlands managed for shorebirds may provide supplemental habitat. We describe an integrative shorebird-waterfowl management strategy used at Tom Yawkey Wildlife Center on South Island, South Carolina, during 3 winter-spring seasons (1991-93). We compared shorebird use and invertebrate density between diked, managed wetlands and adjacent natural coastal mudflat areas. About 3,000 shorebirds overwintered each year at the site. Migration numbers peaked at 15,000-19,000 during late May. In 1991, shorebird density and absolute numbers were higher ( P < 0.05) in managed wetlands at high tide than natural mudflats at low tide. In 1993, we counted shorebird density at low tide both in managed wetlands and Mother Norton Shoals, the largest natural area. During February, shorebird frequency was higher in Mother Norton Shoals and lower in managed wetlands than expected values based on area ( P < 0.005). In contrast, from March to May, shorebird frequency was higher in managed wetlands and lower in natural mudflats than expected ( P < 0.005 for each month). Invertebrate density from March to May was generally greater in managed wetlands than at Mother Norton Shoals, which may explain shorebird preference during that time. Greater invertebrate density did not explain the pattern in February. Mean water depth in managed wetlands for each shorebird species was <5 cm except for American avocet ( Recurvirostra americana ) which used deeper water ( x̄ = 8.4 cm, SD = 4.5). Results indicate that an integrative shorebird-waterfowl management strategy provides supplemental shorebird habitat at high tide, and managed wetlands can be preferred to local natural mudflat areas at low tide.

South Carolina↗