Marsh Birds Research Articles

Effect of the invasive common reed on the abundance, richness and diversity of birds in freshwater marshes

AbstractThe Eurasian genotype of common reed Phragmites australis subsp. australis is rapidly invading freshwater marshes in North America. Several bird species depend upon particular plant assemblages for feeding and reproduction and could be adversely affected by the expansion of this invader. The objective of this study was to evaluate the effect of common reed on the abundance, richness, diversity and site occupancy of bird assemblages in freshwater marshes recently invaded by the plant (southern Quebec, Canada). We conducted fixed‐distance point counts for songbirds (passerines and rails) and visual surveys for waterbirds (ducks, geese and waders) during two nesting seasons (2009 and 2010). There were major structural differences between common reed stands and marsh vegetation assemblages dominated by other plant species (bulrushes, cattails, sedges). However, there was a little difference in abundance, richness, diversity and site occupancy for songbirds. Marsh wren Cistothorus palustris, a wetland specialist, was the only nesting bird that preferred a native plant (cattail) over common reed, probably because common reed stands have low plant diversity and few appropriate nest materials. No major differences were observed in the abundance of waterbirds between invaded and non‐invaded marshes. For most bird species, the water depth of the marsh had more influence on the abundance of individuals and on site occupancy than the composition of the plant assemblage. Common reed stands can therefore be used by generalist and specialist marsh passerines as feeding and reproduction sites. However, it is possible that in southern Quebec, the number and extent of common reed populations have not yet reached a threshold beyond which adverse effects of the invader on avian species could be significant. This study adds to a growing body of evidence showing that the relationship between invasive plants and birds is not straightforward.

Linking multi-temporal satellite imagery to coastal wetland dynamics and bird distribution

Ecosystems are characterized by dynamic ecological processes, such as flooding and fires, but spatial models are often limited to a single measurement in time. The characterization of direct, fine-scale processes affecting animals is potentially valuable for management applications, but these are difficult to quantify over broad extents. Direct predictors are also expected to improve transferability of models beyond the area of study. Here, we investigated the ability of non-static and multi-temporal habitat characteristics to predict marsh bird distributions, while testing model generality and transferability between two coastal habitats. Distribution models were developed for king rail (Rallus elegans), common gallinule (Gallinula galeata), least bittern (Ixobrychus exilis), and purple gallinule (Porphyrio martinica) in fresh and intermediate marsh types in the northern Gulf Coast of Louisiana and Texas, USA. For model development, repeated point count surveys of marsh birds were conducted from 2009 to 2011. Landsat satellite imagery was used to quantify both annual conditions and cumulative, multi-temporal habitat characteristics. We used multivariate adaptive regression splines to quantify bird–habitat relationships for fresh, intermediate, and combined marsh habitats. Multi-temporal habitat characteristics ranked as more important than single-date characteristics, as temporary water was most influential in six of eight models. Predictive power was greater for marsh type-specific models compared to general models and model transferability was poor. Birds in fresh marsh selected for annual habitat characterizations, while birds in intermediate marsh selected for cumulative wetness and heterogeneity. Our findings emphasize that dynamic ecological processes can affect species distribution and species–habitat relationships may differ with dominant landscape characteristics.

Sea level rise and prescribed fire management: Implications for seaside sparrow population viability

In the Chesapeake Bay, Maryland, unusually high rates of sea level rise threaten endemic tidal marsh birds, while prescribed burning benefits these bird populations. Effective conservation of tidal marsh birds requires that management actions be prioritized based on their impact to the long-term population viability for these species. We used a population viability analysis to evaluate the relative influence of two sea level rise scenarios and two prescribed fire management scenarios on the population viability of seaside sparrows, a tidal marsh obligate species, at Blackwater National Wildlife Refuge and Fishing Bay Wildlife Management Area. Marsh loss caused by rising sea levels had a greater impact on seaside sparrow population viability than did prescribed fire. Limiting marsh loss over the next 50years to 15% of the present extent caused a 19% probability of reaching the quasi-extinction threshold, while losing 33% of extant marsh caused a 50% probability of reaching the quasi-extinction threshold. Prescribed fire increased the likelihood of seaside sparrow persistence; increasing the amount of frequently-burned marsh from 12% to 53% lowered the quasi-extinction probability from 0.20 to 0.10. Slowing the rate of marsh loss will have a greater positive effect on seaside sparrow viability than increasing the frequency of prescribed fire. Sea level rise poses the single greatest threat to the long-term persistence of tidal marsh bird populations.

Hydrology influences generalist–specialist bird-based indices of biotic integrity in Great Lakes coastal wetlands

Marsh bird habitats are influenced by water levels which may pose challenges for interpreting bird-based indices of wetland health. We determined how much fluctuating water levels and associated changes in emergent vegetation influence the Index of Marsh Bird Community Integrity (IMBCI) using data collected in Great Lakes coastal wetlands by participants in Bird Studies Canada's Great Lakes Marsh Monitoring Program. IMBCI scores for 90 wetlands in Lake Erie and 131 wetlands in Lake Ontario decreased with decreasing water levels due to decreasing number of marsh-dependent species in Lake Erie and perhaps also in Lake Ontario. The average magnitude of the decrease in scores between extremely high and low water periods for wetlands with sufficient data was 15% in Lake Erie where water dropped 0.9m on average (n=11 wetlands) and 18% in Lake Ontario where water dropped 0.5m (n=7). Scores in Lake Erie increased with increasing Typha due to increasing numbers of marsh-dependent species and decreased with increasing Phragmites due to increasing numbers of generalist species. The opposite was observed in Lake Ontario, perhaps due to denser Typha and sparser Phragmites. Scores were explained by the naturally fluctuating water levels of Lake Erie, which favored Phragmites expansion and the regulated water levels of Lake Ontario which promoted Typha expansion. Scores were influenced by fluctuating water levels and associated changes in emergent vegetation. Inter-annual water level fluctuations should be considered when interpreting any indicator of wetland health that is based on marsh-dependent bird species.

Influence of season and time of day on marsh bird detections

Call-broadcast surveys are frequently used to elicit responses of secretive marsh birds and produce greater detection rates than passive surveys. However, little is known about how detection rates of birds from these surveys differ by season and time of day. We conducted call-broadcast surveys for eight focal species at 56 wetlands throughout Iowa from 15 May–13 June 2010 (early season) and from 15 June–10 July 2010 (late season). Our focal species were Pied-billed Grebe (Podilymbus podiceps), American Bittern (Botaurus lentiginosus), Least Bittern (Ixobrychus exilis), King Rail (Rallus elegans), Virginia Rail (Rallus limicola), Sora (Porzana carolina), Common Gallinule (Gallinula chloropus), and American Coot (Fulica americana). Surveys were conducted in the early morning (30 mins before sunrise to 3 hrs after sunrise) and late evening (3 hrs before sunset to 30 mins after sunset) in accordance with the North American Marsh Bird Monitoring Protocol. We evaluated marsh bird detection rates as a function of a) time of day (morning and evening survey periods), b) season (early and late in the breeding season), and c) wetland size for four species with the greatest detection rates (Pied-billed Grebe, Least Bittern, Virginia Rail, and Sora). We also evaluated the above effects for two species groups; all eight species pooled and all rails pooled. We found significant (P < 0.05) effects on the number of detections for Pied-billed Grebe in response to time of day, time of season, and wetland size; Sora, Virginia Rail, all rails, and all species had an effect of time of season only. Understanding seasonal and time-of-day differences in detection rates, as well as area dependence of secretive marsh birds, will refine existing monitoring protocols by allowing researchers to maximize detection probabilities of target species.

Multiscale Habitat Selection of Wetland Birds in the Northern Gulf Coast

The spatial scale of habitat selection has become a prominent concept in ecology, but has received less attention in coastal ecology. In coastal marshes, broad-scale marsh types are defined by vegetation composition over thousands of hectares, water-level management is applied over hundreds of hectares, and fine-scale habitat is depicted by tens of meters. Individually, these scales are known to affect wetland fauna, but studies have not examined all three spatial scales simultaneously. We investigated wetland bird habitat selection at the three scales and compared single- and multiscale models. From 2009 to 2011, we surveyed marsh birds (i.e., Rallidae, bitterns, grebes), shorebirds, and wading birds in fresh and intermediate (oligohaline) coastal marsh in Louisiana and Texas, USA. Within each year, six repeated surveys of wintering, resident, and migratory breeding birds were conducted at >100 points (n = 304). The results revealed fine-scale factors, primarily water depth, were consistently better predictors than marsh type or management. However, 10 of 11 species had improved models with the three scales combined. Birds with a linear association with water depth were, correspondingly, most abundant with deeper fresh marsh and permanently impounded water. Conversely, intermediate marsh had a greater abundance of shallow water species, such as king rail Rallus elegans, least bittern Ixobrychus exilis, and sora Porzana carolina. These birds had quadratic relationships with water depth or no relationship. Overall, coastal birds were influenced by multiple scales corresponding with hydrological characteristics. The effects suggest the timing of drawdowns and interannual variability in spring water levels can greatly affect wetland bird abundance.

Waterbirds Population, Species Diversity and Similarity Fluctuation in Relation to Water Pollution in Miangaran Wetland, South of Iran

The Miangaran (also called Izeh) marsh located in vicinity (1.5 Km) of Izeh city at Khouzestan province in south of Iran. The wastewater (domestic sewage, urban-ran-off and industrial) of the Izeh city discharge into the south part of the Izeh marsh. The aim of this study was to determine the effect of water quality by comparing the relative number and species richness and diversity of marsh birds in south and north part of marsh, and to determine what landscape variables could be used to predict the relative number and species richness of marsh birds. Determination of species diversity, richness, evenness, similarity, and number of waterbirds in south part (more polluted part) and north part, as a (low-polluted part) of marsh were carried out from July to September 2011. Eighteen species of migratory waterbirds were present in both south (more Polluted) and north (low-polluted) parts of marsh, but total number of waterbirds in north part (4707 individuals) was twice more than south part (2110 individuals) in summer 2011. Maximum similarity between bird communities in south and north part of marsh was 64.57% (0.77 Morista’s index) in September 2011 and Minimum similarity was 13.44% (0.07 Maritsa’s index) in August 2011. Species diversity and richness of north part were more than south part of marsh, and were in range (10, 9, 11) and (14, 15, 15) species in July, August and September respectively. The study revealed that averages of COD, biological oxygen demand, salinity, SO4 and temperature were in range (9.66-102 mg/L), (50-55 mg/L), (0.96-1.6), (0.61-0.78mg/L), (20-21.6 siliceous) in north and south part of marsh in July, August, and September respectively. The pH, EC, Turbidity, DO, BOD, COD, SO4, NO3, salinity and temperature of water in south part were a little more than north part of marsh, but DO was inverse of other chemical parameters, and in north part was more than south part and were in range (4.66 - 2.90mg/L). A little difference between averages of physicochemical parameters of water in two parts of marsh has been cased significantly in number, species diversity, and richness of waterbirds in summer 2011.

Effect of Tide Level and Time of Day on Detection Rate and Abundance of Clapper Rails (Rallus longirostris) in a Mid-Atlantic Tidal Marsh System

Obligate marsh bird detection rates during surveys are affected by the time of day and the tide level, but previous research on both factors has produced conflicting results and no research has been conducted in east coast tidal marshes. Relative abundance and detection rate of Clapper Rails (Rallus longirostris) were compared between morning and evening surveys at high, medium, and low tide levels in Worcester County, Maryland, during 2006. The detection rate of Clapper Rails was greatest in the morning at the medium tide level ( = 0.69, SE = 0.14, F5,40 = 5.87, P = 0.001). Morning surveys ( = 1.2, SE = 0.14) resulted in a greater relative abundance of Clapper Rail detections compared to evening surveys ( = 0.8, SE = 0.12, F1,195 = 5.31, P = 0.022), and surveys done at medium tide level ( = 1.3, SE = 0.17) resulted in greater relative abundance than those conducted at low ( = 0.8, SE = 0.15) or high levels ( = 0.7, SE = 0.15, F2,195 = 6.56, P = 0.002). The results suggest that surveys should be conducted in the morning at medium tide to maximize detection rate of Clapper Rails. The detection rate of obligate marsh birds during surveys is affected by time and tide level so additional research is necessary to determine how these variables affect the detection rate of marsh birds other than Clapper Rails.

A morphometric model to predict the sex of virginia rails (Rallus limicola)

Virginia rails (Rallus limicola) are secretive marsh birds found in freshwater wetlands across much of North American. There is currently no known way to differentiate between the sexes in the field. We suggest the use of morphometric discriminant analysis as an effective method to separate males and females. We compared the length of the culmen, tarsus, wing chord, and middle toe of live birds captured at Ottawa National Wildlife Refuge (Ottawa Co., OH) during the springs of 2002–2011 and museum specimens measured the summer of 2011. We genetically determined the sex of a subset of samples using an intronic region of the chromo-helicase-DNA-binding gene on the Z and W chromosomes. For live birds, 81% of males and 70% of females were classified correctly; and for museum specimens, 71% of males and 80% of females were classified correctly. This technique provides an accurate and simple method of determining Virginia rail sex that can contribute to efforts to better understand population demographics. © 2013 The Wildlife Society.

Status of marsh birds in the wetlands of the Colorado River delta, México

Populations of secretive marsh birds (Rallidae and Ardeidae) have declined in North America in the last decades. Despite drastic habitat changes, the Colorado River delta supports four species of protected marsh birds: California Black Rail, Virginia Rail, Least Bittern and Yuma Clapper Rail. Our goal was to assess the status (2010–2011) and detect population changes (1999–2011) of marsh birds in the Colorado River delta. This effort was focused on the Cienega de Santa Clara and the recent disturbance events that occurred in this wetland (changes in inflows, dredging and wildfires), but included other areas of the delta as well. The Cienega provides critical habitat for the four species, with estimated abundance of 405 California Black Rails, 7152 Virginia Rails, 8652 Least Bitterns and 8642 Yuma Clapper Rails. Populations of these species have remained stable since 1999, with no significant trend, although with some fluctuations in some years. Other wetlands in the delta also provide important habitat, especially El Doctor Wetlands for California Black Rails and Virginia Rails, the Hardy and Colorado rivers for Yuma Clapper Rails and Least Bitterns, and Laguna del Indio for Yuma Clapper Rails. The detections of marsh birds in 2011 were amongst the highest since the monitoring program began in 1999. This was probably linked to the disturbance regime that was recreated with a series of events in the Cienega, including the dredging of sediment, variations of inflows, and an extensive wildfire. Wetlands in the Colorado River delta support the majority of breeding Yuma clapper rails and important populations of other marsh birds. As these are shared species by México and the U.S., the conservation and restoration of the delta should be a shared responsibility.

Diversity and Habitat Distribution of Birds in Coastal Marshes and Comparisons with Surrounding Upland Habitats in Southeastern South America

We studied variation in bird assemblages with plant associations for three different coastal marshes from Southeastern South America (SESA) and assessed how marsh bird assemblages related to nearby upland bird assemblages. We surveyed bird species and plant structure along the tidal gradient of each locality from the low tide level to the upper habitats bordering coastal marshes. Twenty species frequently used coastal marshes, including relatively few migratory species. We found that birds occurring in SESA coastal marshes do not have distributions constrained to coastal marshes. Nonetheless, four bird assemblages were recognized in association with vegetation types and/or sites. Among the recorded coastal marsh species, the bay-capped wren-spinetail (Spartonoica maluroides) is both the most frequent and the most habitat constrained. Bird richness increases steadily along the tidal gradient associated with the increase in vegetation structure, suggesting that bird richness is directly explained by vegetation and indirectly by the physical conditions influencing vegetation structure. Results highlight the importance of SESA middle marshes as habitat for conservation of some threatened SESA grassland birds.

Environmental conditions on wintering grounds and during migration influence spring nutritional condition and arrival phenology of Neotropical migrants at a northern stopover site

Assessing effects of winter habitat quality and environmental conditions on fitness of migratory birds is important to understand factors that regulate migratory bird populations throughout the annual cycle. We evaluated effects of winter habitat occupancy, as inferred from tissue stable-carbon (δ13C) and -nitrogen (δ15N) isotope values, on nutritional condition and arrival date of seven long-distance Nearctic–Neotropical migratory species sampled at Delta Marsh Bird Observatory (DMBO, Manitoba, Canada) during their spring migration to more northerly breeding areas. Additionally, we used a long-term dataset of DMBO to assess the effect of May minimum temperature, May minimum daily temperature, and El Nino–Southern Oscillation (ENSO) index on body condition and spring arrival date. A positive effect of assumed mesic winter habitat on nutritional condition and arrival phenology was detected primarily in species overwintering in the Caribbean (Palm Warbler Setophaga palmarum, Northern Waterthrush Parkesianovaboracensis). We caution, then, against generalizing the results of previous isotopic studies inferring winter habitat use applied to Neotropical migrants wintering in the Caribbean (e.g., American Redstart Setophaga ruticilla) to those species or populations wintering elsewhere and especially away from dichotomous mangrove versus scrub habitats. In general, birds arrived later and in lower nutritional condition during colder springs, and early migrants did not adjust their timing of migration to spring temperature. Early arrival was associated with poorer nutritional condition, and most species had their lowest nutritional condition during the coldest periods of migration. ENSO, probably through its influence on weather and food availability during winter, carried over to northern latitudes and affected both spring arrival date and nutritional condition.

Modeling water management scenarios for the Cienega de Santa Clara, an anthropogenic coastal desert wetland system, based on inflow volumes and salinities

The Cienega de Santa Clara in the Colorado River Delta, Mexico is a self-designed wetland system fed since 1977 by brackish groundwater diverted from the U.S. to Mexico. The vegetated upper portion of the Cienega provides habitat for endangered Yuma-Clappers rails and other marsh birds and fulfills other ecological functions. Outflow water pools in the Santa Clara Slough south of the Cienega and provides habitat for migratory shorebirds. Conditions in the Cienega and Santa Clara Slough could be altered by operation of the Yuma Desalting Plant (YDP), which will divert water from the Cienega and replace it with brine water resulting from the desalting process. Our objective was to integrate water budget components into models predicting the extent of the dominant vegetation (southern cattail, Typha domingensis Pers.) in the marsh and the area of the outflow pool below the marsh in response to different operating scenarios for the YDP. The models are intended to serve as tools for resource managers charged with maintaining this wetland complex. Unlike many wetland water budget models, this one explicitly takes into account salinity as a factor in the water budget. We modeled inflow rates ranging from 1 to 6m3s−1 and inflow salinities ranging from 0 to 6gL−1 Total Dissolved Solids. The model indicates that if the inflow rate is reduced below the current 4–5m3s−1 the vegetated area of the Cienega would decrease in proportion, as would the area of the outflow pool in the Santa Clara Slough. Increases in salinity will also reduce the vegetated area due to the low salt tolerance of T. domingensis. In winter about 90% of inflow water exits the Cienega into the Santa Clara Slough due to low evapotranspiration, and on an annual basis 70% of inflows exit into the Santa Clara Slough. These flushing flows maintain the salt balance in the Cienega. The Santa Clara Slough is periodically flushed by spring tides, making this a sustainable, open wetland system in its present state.

Multi-Species Call-Broadcast Improved Detection of Endangered Yuma Clapper Rail Compared to Single-Species Call-Broadcast

Broadcasting calls of marsh birds during point-count surveys increases their detection probability and decreases variation in the number of birds detected across replicate surveys. However, multi-species monitoring using call-broadcast may reduce these benefits if birds are reluctant to call once they hear broadcasted calls of other species. We compared a protocol that uses call-broadcast for only one species (Yuma clapper rail [Rallus longirostris yumanensis]) to a protocol that uses call-broadcast for multiple species. We detected more of each of the following species using the multi-species protocol: 25 % more pied-billed grebes, 160 % more American bitterns, 52 % more least bitterns, 388 % more California black rails, 12 % more Yuma clapper rails, 156 % more Virginia rails, 214 % more soras, and 19 % more common gallinules. Moreover, the coefficient of variation was smaller when using the multi-species protocol: 10 % smaller for pied-billed grebes, 38 % smaller for American bitterns, 19 % smaller for least bitterns, 55 % smaller for California black rails, 5 % smaller for Yuma clapper rails, 38 % smaller for Virginia rails, 44 % smaller for soras, and 8 % smaller for common gallinules. Our results suggest that multi-species monitoring approaches may be more effective and more efficient than single-species approaches even when using call-broadcast.

An Appraisal of the Use of Hydrogen-Isotope Methods to Delineate Origins of Migratory Saw-whet Owls in North America

Abstract. Northern Saw-whet Owls (Aegolius acadicus) breed throughout the boreal forest of North America, but little is known about their population trends or distribution within this region. Analysis of stable hydrogen isotopes (δ2H) in feathers can delineate origins of a variety of avian migrants, but raptors are reported to have high intra-feather isotopic variance and mean δ2H values higher than predicted from δ2H isoscapes specific to raptor feathers, making assignment of geographic origin sometimes difficult. We examined the applicability of δ2H analysis of saw-whet owl feathers to delineating origins of migrants and to assessing differences in the migratory behavior of adult and young owls by using multiple generations of feathers from owls captured during fall migration at the Delta Marsh Bird Observatory, Manitoba, 2006–2007. Values of δ2H in saw-whet owl feathers were higher than predicted from a δ2H isoscape specific to raptor feathers and from patterns of movements inferred from analysis of ba...

The Birds of the Ciénega de Santa Clara, a wetland of international importance within the Colorado River Delta

The Ciénega de Santa Clara is the largest marsh in the Sonoran Desert and the most important wetland in the Colorado River delta. We present the information on the state of the birds in the Ciénega and a checklist of the species that have been detected at the site. We also summarize the ornithological work that has been conducted and compiled recommendations for bird conservation. A total of 261 species of birds have been detected in the Ciénega de Santa Clara, representing 71% of the species known to the Colorado River delta. The birds of the Ciénega include 189 migratory species (70.4%), 49 year-round residents (18.7%), and 28 breeding visitors (10.7%). Twenty-seven species are federally protected in Mexico, four of them as Endangered, eight as Threatened, and 15 under Special Protection. The Ciénega provides critical habitat for migratory waterbirds, with maximum counts of 280,000 shorebirds in the southern mudflats, as well as for breeding marsh birds, including Yuma Clapper Rails, Virginia Rails and California Black Rails, with maximum estimates of 8600, 7150 and 400 individuals respectively. Other species of concern that occur regularly in the Ciénega include Least Bittern, Snowy Plover, Least Tern, and Large-billed Savannah Sparrow. This wetland also provides important stopover habitat for 81 species of Neotropical migratory landbirds during their northbound spring migration, particularly for Wilson's Warbler, Swainson's Thrush, Yellow Warbler, Pacific-slope Flycatcher, and Willow Flycatcher. Binational cooperation is essential to protect the Ciénega in the long-term, especially in terms of dedicating the necessary water for its maintenance. Active management actions are also becoming an important part of habitat conservation, including land protection mechanisms, sediment removal, and fire management.

Habitat Associations of Secretive Marsh Birds in Iowa

Drastic losses of wetland habitats across North America over the past century have resulted in population declines of many marsh birds therefore emphasizing the need for proper management of remaining wetlands for the conservation of marsh birds. Our objective was to evaluate the probability of site occupancy of secretive marsh birds in Iowa in response to habitat variables at multiple scales. We conducted call-broadcast surveys for eight species of marsh birds at wetlands in Iowa from 16 May–15 July 2009 and from 20 April–10 July 2010. We utilized occupancy models in Program MARK to estimate site occupancy probability based on habitat covariates for four species with the most detections (Pied-billed Grebe [Podilymbus podiceps], Least Bittern [Ixobrychus exilis], Virginia Rail [Rallus limicola], and Sora [Porzana carolina]). Wetland size had a positive effect on site occupancy for Least Bitterns, water depth positively affected site occupancy for Pied-billed Grebes and Least Bitterns, and percent cover of cattail positively affected site occupancy for Virginia Rails. Knowing habitat associations of secretive marsh birds in Iowa will allow us to provide guidance on wetland restoration and management decisions that will aid the conservation of these birds.

Effects of coypu (Myocastor coypus) abundances and diet selection on a wetland of the Patagonian steppe

We assessed diet selection, impact on vegetation, and explored habitat relationships with marsh birds of coypus (Myocastor coypus) in a steppe lagoon in Argentinean Patagonia. In two consecutive springs, abundance and spatial use of the coypus and nesting marsh birds were estimated by direct counts. The coypu was a selective consumer with seasonal variations in food items, and Myriophyllum sp. and Schoenoplectus californicus dominated its diet. Coypus and marsh birds showed a differential spatial use when rushes cover was high. However, when rushes cover decreased by coypu browsing, there was a similar use of space, and marsh birds were displaced to nest on the open water and other poorly protected areas of the rushes. Our results suggest that high abundances of coypu can have a detrimental effect on wetland ecosystems. Systematic monitoring and evaluation of their effects on wetlands in recently colonized areas is recommended.

Modeling climate change impacts on tidal marsh birds: Restoration and conservation planning in the face of uncertainty

The large uncertainty surrounding the future effects of sea‐level rise and other aspects of climate change on tidal marsh ecosystems exacerbates the difficulty in planning effective conservation and restoration actions. We addressed these difficulties in the context of large‐scale wetland restoration activities underway in the San Francisco Estuary (Suisun, San Pablo and San Francisco Bays). We used a boosted regression tree approach to project the future distribution and abundance of five marsh bird species (through 2110) in response to changes in habitat availability and suitability as a result of projected sea‐level rise, salinity, and sediment availability in the Estuary. To bracket the uncertainty, we considered four future scenarios based on two sediment availability scenarios (high or low), which varied regionally, and two rates of sea‐level rise (0.52 or 1.65 m/100 yr). We evaluated three approaches for using model results to inform the selection of potential restoration projects: (1) Use current conditions only to prioritize restoration. (2) Use a single future scenario (among the four referred to above) in combination with current conditions to select priority restoration projects. (3) Combine current conditions with all four future scenarios, while incorporating uncertainty among future scenarios into the selection of restoration projects. We found that simply using current conditions resulted in the poorest performing restoration projects selected in terms of providing habitat for tidal marsh birds in light of possible future scenarios. The most robust method for selecting restoration projects, the “combined” strategy, used projections from all future scenarios with a discounting of areas with high levels of variability among future scenarios. We show that uncertainty about future conditions can be incorporated in site prioritization algorithms and should motivate the selection of adaptation measures that are robust to uncertain future conditions. These results and data have been made available via an interactive decision support tool at www.prbo.org/sfbayslr.

Substantive Parenting Arrangements: The Tragedy of the Snipe Hunt

The snipe is a shore or marsh bird that is difficult for even trained hunters to catch. Inexperienced hunters (or campers) are teased with the impossible (or imaginary, in the case of campers) task of going on a snipe hunt. The snipe hunt has therefore become a metaphor for an impossible task, usually undertaken by the unwary and unequipped in the fog or dark. Developing the “best” child custody standards has become rather like a snipe hunt, for policy makers use (or misuse) studies that are often not up to the task in order to serve adult interests that are necessarily at odds. When things are not resolved, they resort to other strategies (such as unfounded accusations of domestic violence or of the “parental alienation syndrome”) that are the legal equivalents of banging rocks together, completely ineffective except for hurting the child.In the United States, children’s voices are mediated primarily through their parents. Most of the time this is the best solution, but in cases of conflict between the parents, or any time when parents’ and children’s interests conflict, a variety of processes ostensibly safeguard the child. While over the last thirty years there has been a focus on various sorts of ADR, a critical question in determining “best interests” involves the standard that should focus the decisionmakers’ attention. In particular, should individual decisionmaking protect the most vulnerable parents and their children, who may well have their cases decided by a judge, or should rules be more determinate to facilitate non-conflicted resolution of the vast majority of cases? What is the appropriate role of social science research in making this substantive choice or reaching the best conclusion from the child’s perspective?