This study documents patterns of primary feather molt and body mass changes in Least Sandpipers (Calidris minutilla) and Western Sandpipers (C. mauri) in Ensenada de La Paz, México. Both species use the same habitats and complete an uninterrupted primary feather molt between late July and October. Average timing of Least Sandpiper primary molt was from 29 July to 21 September (duration of 54 days), while Western Sandpipers molted from 29 July to 29 September (duration of 62 days). Molt models of individual primaries suggested that the molt of Least Sandpipers starts after all individuals have arrived in the study area, whereas the molt of Western Sandpiper starts before all individuals have arrived; the heavier Western Sandpiper tends to grow more feathers simultaneously than the Least Sandpiper. While Western Sandpipers are heavier than Least Sandpipers at the start of molt, both species decrease their body mass over the molt period. Although Least and Western sandpipers have similar natural histories, they show different primary molt patterns in Baja California Sur.

The millions of wetlands that define the Prairie Pothole Region (PPR) harbor large proportions of continental populations of several species of North American waterfowl, waterbirds, and shorebirds. The PPR also has some of the highest wind energy potential in the United States. Thousands of wind turbines are being erected in the PPR to produce electricity and have the potential to affect migratory bird populations through collisions, displacement, barriers to movement, habitat fragmentation, and habitat loss. We assessed occurrence of waterbirds and shorebirds from 2008 through 2010 on wetlands in two wind energy development sites, defined as wetlands within 805 m of a wind turbine, and two reference sites in the PPR of North and South Dakota. We conducted 10,321 wetland visits on 3,542 individual wetland basins and related bird occurrence to wetland characteristics, upland characteristics, survey type (roadside vs. off-road), seasonal timing of sampling, year of sampling, and site type (wind energy development vs. reference). Models characterizing occurrence of Willet (Catoptrophorus semipalmatus), Marbled Godwit (Limosa fedoa), Wilson's Phalarope (Phalaropus tricolor) and Black Tern (Chlidonias niger) indicated that occurrence varied with wetland characteristics and among sites and years, was not substantially reduced on either wind energy site, but was slightly and consistently lower on one of the wind energy sites for the three shorebird species. Our results suggest that wetlands have conservation value for these species when wind turbines are present, but additional sampling across time and space will be necessary to understand the effects of wind turbines on shorebird and waterbird presence, density, survival, and reproductive success.

Mauritanian Spoonbills (Platalea leucorodia balsaci) only breed at Banc d'Arguin, Mauritania, West Africa. Their populations have declined; however, nothing is known about possible ecological factors involved, including their primary food and foraging habits. Home range sizes, habitat selection, and foraging rhythm in six adult Mauritanian Spoonbills were documented by attaching backpack harnesses with solar-powered satellite GPS-transmitters. Based on 18 bird-months of data (5,844 selected ground positions) collected between 2008 and 2010, these individuals never left the study area centered on the island of Tidra. The fixed kernel home range size was 23–101 km² ( = 62 km²) and the core area 2–14 km² ( = 7 km²). Home range sizes did not differ between breeding and non-breeding seasons. Mauritanian Spoonbills fed only in intertidal areas where they preferred the seagrass-covered (Zostera noltii) areas and they fed primarily during the ebbing tide. Furthermore, the GPS-positions away from the high tide roosts were strongly associated with creeks dissecting the seagrass beds. During the non-breeding season, foraging occurred throughout the 24-hr period, but during the breeding season they foraged exclusively by night.

The Torrent Duck (Merganetta armata) inhabits the torrential rivers of the Andean mountains. As part of a long-term study, two rivers important for hydroelectric production were surveyed in Central Chile. Monthly indices of Torrent Duck abundance and reproduction were recorded at 74 sampling points distributed along 35.4 km of river between 2007 and 2009. Habitat variables were measured to determine the factors that influence species abundance. The number of rapids, gradient, total flow, water velocity, relative position to hydropower intakes and abundance of conspecifics were identified as important attributes in Torrent Duck habitat preferences. Torrent Ducks were observed in selected sections of rivers where the presence of rapids, high slopes and high water velocity occurred. These conditions were influenced by the width and shape of the river bed. Spatial segregation among individuals suggests the effect of territoriality. Torrent Ducks tended to avoid the presence of high vehicular traffic roads and sections downstream of the hydropower intakes. The hydropower intakes showed no impact on either the chemistry of the water or the composition of the macroinvertebrate community. The negative effects of hydroelectric power production on Torrent Duck populations could be mitigated through the modification of the shape of the river channel.

Twenty adult male American Bitterns (Botaurus lentiginosus) were marked on summer range in central North America with satellite tracking Platform Transmitter Terminals (PTTs) to document migration routes and wintering range. Nineteen complete fall migration routes were documented for 17 individuals. Of the successful migrations, 63% (n = 12) went to southern Florida, 32% (n = 6) to southern Louisiana, and 5% (n = 1) to the Gulf coast of Texas. Spring migrations for nine birds were documented, and 78% (n = 7) showed fidelity to breeding range. Two complete migrations for two individuals were documented, and they demonstrated fidelity to winter range. The longest, fastest movement documented was 2,300 km in less than 74 hr. Extensive, post-breeding dispersal was not observed in the adult male American Bitterns in this study. Six male American Bitterns were marked with PTTs on winter range in Florida and Texas. Spring migration for these birds was documented to Nebraska, North Dakota, Saskatchewan, Manitoba and Ontario. Sixty-seven American Bitterns were marked with Very High Frequency radio transmitters on summer ranges, and 16% (n = 11) were located on wintering grounds used by the satellite-tracked birds, further documenting the importance of the Everglades and the Louisiana coast as winter habitat for American Bitterns that breed in Central North America.

Gull-billed Terns (Gelochelidon nilotica) are among the most widespread, yet scarce, Charadriiformes in the world. Two subspecies are recognized in the United States: G. n. aranea breeds along the U.S. Atlantic and Gulf coasts and G. n. vanrossemi breeds in the Salton Sea and San Diego Bay of California. Conservation concerns exist for the species due to its low abundance in the United States and apparent declines in some parts of its North American range. We used nuclear microsatellite markers and mitochondrial DNA sequences to assess genetic diversity and differentiation patterns among Gull-billed Tern populations from Virginia, Texas, and California. We also tested for evidence of population bottlenecks, and evaluated the support our data provide for the North American subspecies. Genetic diversity was highest in Texas and underscored the importance of habitat in that large population. Significant population differentiation existed, but could not be consistently identified using various analytical approaches and suggested that the magnitude of differentiation was low. No evidence for bottlenecks was identified. Our data could not distinguish individuals from different subspecies and therefore do not support the current intraspecific taxonomy. Tenable explanations for many findings are related to the low site tenacity demonstrated by the species.

Animal movements and habitat selection within the home range, or microhabitat selection, can provide insights into habitat requirements, such as foraging and area requirements. The King Rail (Rallus elegans) is a wetland bird of high conservation concern in the United States, but little is known about its movements, habitats, or demography. King Rails (n = 34) were captured during the 2010–2011 breeding seasons in the coastal marshes of southwest Louisiana and southeast Texas. Radio telemetry and direct habitat surveys of King Rail locations were conducted to estimate home ranges and microhabitat selection. Within home ranges, King Rails selected for greater plant species richness and comparatively greater coverage of Phragmites australis, Typha spp., and Schoenoplectus robustus. King Rails were found closer to open water compared to random locations placed 50 m from King Rail locations. Home ranges (n = 22) varied from 0.8–32.8 ha and differed greatly among sites. Home range size did not vary by year or sex; however, increased open water, with a maximum of 29% observed in the study, was correlated with smaller home ranges. Breeding season cumulative survivorship was 89% ± 22% in 2010 and 61% ± 43% in 2011, which coincided with a drought. With an equal search effort, King Rail chicks and juveniles observed in May-June decreased from 110 in 2010 to only 16 in the drier year of 2011. The findings show King Rail used marsh with ≤ 29% open water and had smaller home ranges when open water was more abundant.

Seabirds are important bio-indicators for marine ecosystem conservation. Monitoring at logistically-challenging seabird colonies takes extensive resources and expensive man-hours to complete. The use of remote time-lapse photography to collect population parameters at seabird colonies is a novel way to reduce researcher effort while collecting valuable data. To illustrate the applicability of this method, data were collected at a Thick-billed Murre (Uria lomvia) colony on Kippaku, Greenland. Time-lapse photography was used to take pictures once per hour of a predetermined study plot for the duration of the breeding season, and the pictures were then analyzed using GIS software. By using a photo-capture interval of one picture per hour during one murre breeding season, the study showed a seasonal trend in attendance peaking in the mid chick-rearing period, a diurnal trend with a small peak at ca. 07:00 hr and a larger peak at ca. 19:00 hr. The study showed that careful choice of photo-capture interval is important to reduce the possibility of misrepresenting the diurnal trend of the study species. Compared to the 1-hr photo-capture interval, intervals of 2 and 4 hr accurately depicted the diurnal trend, while a 3-hr interval showed the trend but with a misrepresentation of the first attendance peak. A 5-hr interval introduced stochastic effects that did not show the correct diurnal trend. The proposed method can be applied to colonial breeding seabirds and/or other similar systems for population monitoring. Researcher effort and costs associated with data collection for population monitoring of seabird colonies can be greatly reduced and population estimates can be drastically improved by the use of remote time-lapse photography.

Barrier islands provide numerous ecosystem functions and services, including critical breeding habitat for many waterbird species. Louisiana's barrier islands are experiencing rapid land loss and habitat degradation. Restoration of barrier islands has become a high priority in Louisiana and barrier island degradation has increased waterbird reliance on restored dredge material islands. To improve restoration and management of barrier islands, we investigated the hatching success of Black Skimmer (Rynchops niger) and determined important habitat characteristics for their hatching success. Nest monitoring and nest habitat characteristics were measured at breeding colonies on the Isles Dernieres Barrier Island Refuge, Louisiana, in 2009 and 2010. Hatching success varied greatly for Black Skimmers (1–84%). Predation, flooding, and competition were the three main causes of nest failure. Habitat modeling identified nest elevation relative to the high-tide line and distance to high-tide line as important habitat characteristics. Continued restoration to build landmass on the islands is necessary to maintain quality nesting areas for Black Skimmers. Additionally, dredge applications to increase elevation, vegetation management, and predator control can provide more quality habitat and increase hatching success.

Tropicbirds (order Phaethontiformes) are a well-studied seabird taxon, but there have been no published studies on sexual size dimorphism. Here, we investigated sexual size dimorphism in the Red-billed Tropicbird (Phaethon aethereus) and the White-tailed Tropicbird (P. lepturus), and evaluated the applicability of using morphometrics and discriminant functions to sex birds in the field. We sampled Red-billed Tropicbirds (n = 160) and White-tailed Tropicbirds (n = 57) in the Atlantic Ocean off the coast of Brazil. Each individual had seven morphometric traits measured and blood sampled for molecular sex determination. Discriminant functions were generated using generalized linear models (GLM). Red-billed Tropicbirds had significant male-biased intersexual differences in bill length, wing chord, nostril-to-bill-tip, and head-plus-bill, and the best GLM included bill length and wing chord. White-tailed Tropicbirds were characterized by significant intersexual differences for wing chord, with females larger than males, and the best GLM for this species included wing chord, bill width, and bill depth. Discriminant functions had accuracy similar to those used for other seabird species with similar body sizes.

Recovery of endangered birds often involves population establishment through introduction of captive-reared individuals. Growth of a captive-reared Whooping Crane (Grus americana) population introduced into central Wisconsin is currently limited by a high rate of nest desertion, which is thought to possibly be related to poor general nest attentiveness. Whooping Crane nest attentiveness and associated covariates were studied. Egg infertility and embryonic death rates were assessed as well as their effects on daily nest survival estimates. Techniques to minimize predation exposure of unattended eggs were developed and evaluated. Most Whooping Crane pairs deserted their eggs and all left them unattended. Nest desertion was associated with poor nest attentiveness. Variables related to age of the nesting pair were useful for modeling nest attentiveness. Daily nest survival estimates based solely on adult presence potentially produced inflated measures. Results suggest management interventions can minimize predation exposure of unattended eggs. Bypassing a portion of incubation has the additional advantage of simultaneously addressing nest failure and maximizing productivity.

The foraging behavior of Wood Storks (Mycteria americana) has been studied extensively because of their dramatic population decline and endangered status. The foraging by Wood Storks at an arribada beach with olive ridley sea turtles (Lepidochelys olivacea; turtle) at Ostional, Costa Rica, was examined to determine their depredation behavior on turtle eggs and hatchlings. Wood Storks, in association with Black Vultures (Coragyps atratus), foraged on turtle nests exposed by stream, tidal, and wind erosion, and on nests dug up by dogs (Canis familiaris). Wood Storks also foraged on emerging turtle hatchlings and those crawling to the sea. Wood Storks concentrated near stream beds where nearly half of the predation events (eggs/hatchlings being eaten) occurred. Usually, one to three Wood Storks fed at a turtle nest; an average of 87% of the Wood Storks that were within 5 m of a turtle nest obtained eggs or hatchlings. The number of Wood Storks present and feeding, and the percent feeding, depended upon feeding location, time of day, and whether they were feeding on exposed nests or on emerging hatchlings. An average of two Wood Storks per 30 sec obtained food at nests with exposed eggs, compared with four at nests with emerging turtle hatchlings. Most Wood Storks fed at nests exposed at stream banks (60%) or by tides (23%). Wood Storks had little effect on success of olive ridley sea turtles at Ostional because of the very large number of nesting female turtles, the small population of Wood Storks, and that most turtle hatchlings emerge at night when Wood Storks did not forage. Wood Storks were scared off by people during the peak daylight hatching period, and most Wood Storks and Black Vultures foraged at turtle nests exposed by wind, rain, tides, and dogs. The only viable olive ridley sea turtle offspring Wood Storks fed on were emerging hatchlings and those that crawled to the sea during the daylight.

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, F_5,40 = 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, F_1,195 = 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, F_2,195 = 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.

The structure of the waterbird community at Lago Salso in Southern Italy, Apulia, was surveyed over a 4-year period (2003–2006), during the breeding season (May-July). Lago Salso is an artificial lake with high water levels. Flooding of the surrounding fields, due to copious seasonal rainfalls, occasionally forms vast swampy wetlands around Lago Salso. The variation in waterbird structure and composition, concomitantly with the occurrence of these flooded habitats, is described. In particular, during 2003–2005 there was little variation in annual species richness and diversity at the lake. However, in 2006 the waterbird community changed in species composition and significantly increased in species richness (from 21 ± 3.8 to 32 ± 2.5 species) and abundance values (from 222 ± 167 to 988 ± 42.4 individuals) with the presence of wet grasslands. Lago Salso is one of the most Important Bird Areas on the Italian peninsula, and the occurrence of several species with high conservation value almost exclusive to wet grassland has important implications from a conservation point of view. The formations of temporary flooded meadows are rare in the south of Italy, and our results emphasize the need to define management guidelines for the maintenance of such flooded grasslands.

Senescence is a decline in body function with advanced age that manifests itself in birds as a decrease in survival rates or reproduction. Senescence is difficult to study in free-ranging birds because few birds reach old age and few studies last long enough to identify those birds that do. For 21 years, I studied lifelong reproduction among Canada Geese (Branta canadensis) nesting in New Haven County, Connecticut. These data were used to determine the impact of old age on female and male fecundity during the current year and during the remainder of the birds' lives. Old-aged geese were relatively common in this population; 15% of recruited geese lived 10 years, 3% lived 15 years, and one female lived 20 years. Females that nested when they were between 5 and 9 years old had a mean clutch size of 4.5, brood size at hatching of 3.4, and brood size at fledging of 2.9. Females that nested when they were at least 10 years old had a mean clutch size of 4.7, brood size at hatching of 3.4, and brood size at fledging of 3.3. These variables were independent of age for both sexes. Future reproduction (number of future nesting years and future production of eggs, hatchlings, and fledglings) declined with parental age for males but not females. Body mass of nesting birds did not change with age for either males or females. These results provided evidence of an effect of senescence in male Canada Geese but not females. The terminal investment hypothesis (i.e., that parental investment should increase as birds become older) was not supported for either sex.

This paper describes the interspecific fostering of two Ring-billed Gull chicks (Larus delawarensis) following natural adoption by a pair of Caspian Terns (Hydroprogne caspia) at Gull Island, Presqu'ile Provincial Park, Ontario, Canada, in 2011. Naturally-occurring, interspecific adoptions among waterbirds are rare and those between distantly-related species have not been confirmed to produce fledglings. The observation of one Ring-billed Gull chick being raised by Caspian Terns beyond fledging (approximately 46 days of age) appears to be the first record of successful adoption between different taxonomic families of waterbirds. Behavior, provisioning rate, and growth of chicks were recorded to document this adoption. During linear growth, the mass of the adopted Ring-billed Gull chicks were close to, or even exceeding, maximum mass of Ring-billed Gull chicks raised by their natural parents. After this period, however, the adoptive Caspian Tern parents reduced provisioning rates below those recorded for conspecifics and the adopted Ring-billed Gull chicks lost mass, one of which left the territory prematurely and died. Although initial circumstances leading to the adoption were unclear, that one Ring-billed Gull chick was ultimately fledged by Caspian Terns is remarkable given the different provisioning methods and diet of these species.