Regular surveys of waterbird colonies are needed to identify changes in abundance and distribution. Consistent surveys have been maintained in some regions, but one area where updated surveys were needed was southern Manitoba, where Lakes Winnipeg, Winnipegosis and Manitoba had not been jointly surveyed since 1979. In mid-June, 2012, an aerial survey of the region was conducted using digital photography to estimate abundance of six colonial waterbird species that are regular breeders on these lakes. Breeding by at least one of the six species was confirmed at 131 locations. Double-crested Cormorant (Phalacrocorax auritus) was the most abundant breeder (43,388 pairs, 47 colonies), followed by Ring-billed Gull (Larus delawarensis, 41,819 pairs, 67 colonies), American White Pelican (Pelecanus erythrorhynchos, 12,680 pairs, 20 colonies), Common Tern (Sterna hirundo, 7,950 pairs, 31 colonies), Herring Gull (L. argentatus, 4,013 pairs, 90 colonies) and Caspian Tern (Hydroprogne caspia, 3,207 pairs, 14 colonies). Comparisons with earlier surveys in this region suggest that all six species have increased in abundance from the 1970s when populations were still recovering from earlier threats. However, Double-crested Cormorants, Caspian Terns and Common Terns show evidence of declines since the early 1990s. Standardized surveys of colonial waterbirds on these lakes should be maintained at 10-year intervals similar to the Great Lakes Monitoring Program.

Barrier islands in Louisiana and elsewhere in the northern Gulf of Mexico region provide valuable breeding habitat for numerous waterbird species; however, these islands are also deteriorating at an alarming rate. Management and conservation of waterbird species in these dynamic environments require a better understanding of the breeding biology for northern Gulf of Mexico populations. Productivity parameters were investigated for Royal (Thalasseus maximus) and Sandwich (T. sandvicensis) terns at the Isles Dernieres Barrier Island Refuge in Terrebonne Parish, Louisiana, during the 2009 and 2010 breeding seasons. Mean hatching success for Royal Tern was 77% (n = 169 nests), while Sandwich Tern hatching success was 75% (n = 130 nests). For both Royal and Sandwich terns, the estimated probability that a chick survived from hatching to fledging age was 55% (n = 630 nestlings). Overall, estimated breeding success for Royal and Sandwich terns was 42.3% and 41%, respectively. Chick growth rates were similar for both species and among islands, suggesting similar habitat quality among islands of Isles Dernieres Barrier Island Refuge. Growth rates (K) for both Royal and Sandwich terns were greatest for tarsus (K = 0.194 and K = 0.184, respectively), followed by mass (K = 0.143 and K = 0.164, respectively), and then wing cord (K = 0.125 and K = 0.110, respectively). Future studies evaluating causes of chick mortality would provide insight into the quality of habitat provided during this life stage. Chick growth rates may also be a useful indicator of ecological change and response to disturbances such as the Deepwater Horizon oil spill.

Foraging habitat conditions (i.e., water depth, prey biomass, digestible energy density) can be a significant predictor of foraging habitat selection by wading birds. Potential foraging habitats of Whooping Cranes (Grus americana) using marshes include ponds and emergent marsh, but the potential prey and energy availability in these habitat types have rarely been studied. In this study, we estimated daily digestible energy density for Whooping Cranes in different marsh and microhabitat types (i.e., pond, flooded emergent marsh). Also, indicator metrics of foraging habitat suitability for Whooping Cranes were developed based on seasonal water depth, prey biomass, and digestible energy density. Seasonal water depth (cm), prey biomass (g wet weight m^-2), and digestible energy density (kcal g^-1m^-2) ranged from 0.0 to 50.2 ± 2.8, 0.0 to 44.8 ± 22.3, and 0.0 to 31.0 ± 15.3, respectively. With the exception of freshwater emergent marsh in summer, all available habitats were capable of supporting one Whooping Crane per 0.1 ha per day. All habitat types in the marshes had relatively higher suitability in spring and summer than in fall and winter. Our study indicates that based on general energy availability, freshwater marshes in the region can support Whooping Cranes in a relatively small area, particularly in spring and summer. In actuality, the spatial density of ponds, the flood depth of the emergent marsh, and the habitat conditions (e.g., vegetation density) between adjacent suitable habitats will constrain suitable habitat and Whooping Crane numbers.

Previous efforts to estimate the daily energy expenditure of American Black Ducks (Anas rubripes) have relied upon diurnal behavior observations or predictive allometric equations. American Black Duck behavior was quantified during morning crepuscular, diurnal, evening crepuscular and nocturnal periods to create a 24-hr time-energy budget. Behaviors and energy expenditure differed between periods and months, with hourly energy expenditure highest during the morning crepuscular period and lowest during the nocturnal period. Daily energy expenditure estimates based on a 24-hr time-energy budget were lower than estimates calculated from extrapolated diurnal behavioral data as well as a predictive allometric equation that uses a generalized dabbling duck resting metabolic rate. However, there was no difference between the 24-hr time budget and a predictive allometric equation using American Black Duck specific resting metabolic rates. Future researchers and managers should acknowledge the assumptions of each methodology to estimate daily energy expenditure when using a bioenergetic approach to estimate carrying capacity.

Wetland loss has led to population declines of many species of North American marsh birds. However, due to the secretive nature of many of these species, there is uncertainty about their population status and habitat requirements. Recently developed techniques, such as the Standardized North American Marsh Bird Monitoring Protocol and analytical methods that account for variable detection probabilities, can be used to improve both the quality and quantity of information about secretive marsh birds. In 2009 and 2010, point counts were conducted using the marsh bird monitoring protocol to count Least Bittern (Ixobrychus exilis), Purple Gallinule (Porphyrio martinica) and Limpkin (Aramus guarauna) in the Kissimmee Chain of Lakes, Florida. Habitat factors thought to influence abundance were compared using competing hierarchical mixture models. Abundance of Least Bittern had a positive relationship with amounts of emergent vegetative cover and interspersion (i.e., vegetation to water edge). Purple Gallinule abundance was positively related to percentage of area cover by floating-leaved vegetation, interspersion and diversity of vegetation type. Limpkin abundance was non-linearly related to vegetation cover in both years. In 2009, Limpkin abundance was positively related to vegetation to water edge and vegetation type diversity, and negatively related to vegetation edge in 2010. Results demonstrate that marsh habitats with greater amounts of vegetative cover, interspersion, and vegetation diversity will support the greatest abundance of this suite of marsh birds.

As seabird nesting colonies have become concentrated on fewer managed islands, available nesting habitat for open-ground nesters such as Common Terns (Sterna hirundo) has rapidly become overgrown by guanofertilized vegetation, leading managers to try various methods of vegetation control to open usable nesting habitat. Two of these methods, burning and synthetic weed barrier treatments, were tested in the summers of 2009 and 2010 to assess their ability to open and maintain Common Tern nesting habitat on two nearshore seabird nesting islands in Maine. Treatments were applied to overgrown habitat pre-nesting, and vegetation regrowth and Common Tern nest and fledging success were monitored in treated plots, untreated vegetation plots and occupied Common Tern nesting habitat. Burned areas did not remain open for the full nesting season, but regrew shortly after egg-laying, creating unsuitable vegetation structure and leading to near-complete nest failure in these plots. However, vegetation characteristics produced by the two different weed barrier treatments—one a layer of muslin fabric overlaying newspaper mulch and the other a mosaic of synthetic turf and open ground—were similar to vegetation in pre-existing Common Tern nesting habitat throughout the season. Common Tern nest and fledging success was similar in weed barrier plots (1.37 chicks/pair) and pre-existing Common Tern nesting habitat (1.38 chicks/pair). While burning may not be a useful technique for creating nesting habitat, synthetic weed barriers offer a promising short-term solution to vegetation overgrowth in nesting habitat of Common Terns and species with similar habitat requirements.

Benthic substrate has a large impact on aquatic plant and invertebrate assemblages and likely directly or indirectly influences waterbird distributions. The association of birds with various substrates can be important in survey design or habitat management. Northern Shoveler (Anas clypeata), Common Goldeneye (Bucephala clangula), Eared Grebe (Podiceps nigricollis), Ring-billed Gull (Larus delawarensis) and California Gull (L. californicus) densities on the hypersaline Great Salt Lake, Utah, were estimated to determine the association of bird distributions with benthic substrates. Three of the four groups of species monitored had densities that varied by benthic substrate; gulls were the exception. Eared Grebes occurred at the highest densities over calcareous reef-like structures known as bioherms, either as a result of ideal water depths for foraging or greater prey densities, than over other substrates. The highest densities of Northern Shovelers and Common Goldeneyes were observed over mud substrates. This was likely due to mud being common near freshwater inflow sites and in lower salinity bays, areas waterfowl concentrate in because of the lower osmoregulatory demands compared to more pelagic areas of the Great Salt Lake. Knowing the relationship between waterbird densities and substrate will help managers estimate avian populations on hypersaline lakes.

The dietary compositions of the three most abundant tern species breeding on Nakhilu and Omol-Karam Islands in the Persian Gulf were investigated to determine the dietary segregation between sympatric breeders. Chick dietary samples were collected from Bridled Tern (Sterna anaethetus), Lesser Crested Tern (S. bengalensis) and Swift Tern (S. bergii) in the 2010 and 2011 breeding seasons. Fish prey dominated the diet of the community (99% of prey consumed), although shrimps (primarily the Green Tiger prawn (Penaeus semisulcatus) were present in the food samples from Lesser Crested and Swift tern chicks. Regurgitates of Bridled Tern contained on average 12.48 ± 1.13 prey items (Range = 3–30, n = 31), Lesser Crested Tern contained 1.14 ± 0.01 (Range = 1–6, n = 365) and Swift Tern contained 1.08 ± 0.01 (Range = 1–4, n = 132). Pianka Overlap Index (O_jk) in food type was highest between Lesser Crested Tern and Swift Tern (0.98), while there was less similarity between Bridled Tern and Lesser Crested Tern (0.21) and Bridled Tern and Swift Tern (0.16) prey items. The results showed significant difference between the prey selected among the three tern species studied here in weight and length. Prey length and weight increased from 1–2-week-old chicks to 5–6-week-old chicks in both the Lesser Crested and Swift terns. Although there is high dietary overlap in Lesser Crested and Swift terns, they are segregated in terms of prey size, which likely reduces competition for prey. Although, there was some overlap between the diets of the three tern species, diet segregation on the basis of prey species and prey size are the main factors that should contribute to reduced competitive interactions for food resources.

Strong winters may increase mortality in avian species, with potentially severe consequences for populations. A period of 10 cold days during an otherwise mild winter occurred in the Wadden Sea during February 2012, causing a mass mortality of more than 1,100 Eurasian Oystercatchers (Haematopus ostralegus). This study investigated whether mortality was highest in certain bird-classes (sex, age, diet specialization). By comparing dead with live individuals captured before and after the cold spell, significantly more immature Eurasian Oystercatchers were found dead (> 60%) than expected. Sex ratio did not differ significantly between dead and live individuals, the proportion of males being higher in both dead and live birds. All the dead individuals collected showed significantly smaller body masses (overall mean: 324 g) than live ones (overall mean: 457 g). Few individuals showed internal lesions or anatomical abnormalities, and no influenza virus was found. Dead Eurasian Oystercatchers had completely empty stomachs in 25% and 37% of the individuals in both study areas, Büsum and Amrum, respectively; all other individuals showing only few prey remains. The most frequent prey items were common cockles (Cerastoderma edule). Based on bill shapes, most of the dead Eurasian Oystercatchers were bivalve specialists, and fewer than expected worm eaters died. From band recoveries (n = 19), many of the dead individuals originated from Scandinavia (37%). The main reason for the high mortality appeared to be low food availability and quality before the cold spell combined with sudden low temperatures.

The Red-legged Cormorant (Phalacrocorax gaimardi) is a neotropical cormorant with a moderately small population and is currently categorized as “Near Threatened” by the International Union for Conservation of Nature. The Red-legged Cormorant is distributed only along the coasts of Peru, Argentina and Chile; however, the most important breeding population for this species occurs within a small area in Chile. Between 1998 and 2000, the entire breeding population size of the Red-legged Cormorant and its distribution in Chile were determined, but some areas were poorly surveyed. The breeding population sizes of the Red-legged Cormorant were surveyed along the Araucania coast, an area in south-central Chile not considered in previous studies. A total of 3,175 nests and 13,018 adults were distributed over 10 breeding colonies along the Araucania coast. Our results increased the known breeding population size of the Red-legged Cormorant in Chile by almost 62% (from 5,018–5,218 to 8,193–8,393 breeding pairs) and the rangewide population estimate by almost 43% (from 30,000 to 43,018 individuals). This area could be one of the most important breeding areas for this species throughout its range. Currently, the colonies of Piureo-Puaucho (1,506 nests), Nigue (1,009 nests) and Punta Ronca (Queule) (964 nests) represent almost 42% of the breeding population of this species in Chile, so these breeding sites should be a priority for conservation efforts.

A method for trapping adult herons and egrets in foraging habitats is described. This method will give researchers access to adult members of Ardeidae. Over five trapping seasons, Great Egrets (Ardea alba) and Snowy Egrets (Egretta thula) (n = 78) were captured in non-tidal areas. The technique used decoys, live bait in basins and modified foot-hold traps. It is not appropriate for catching many birds at one time. The method could be modified for similarly-sized species.

Three avian footprints from a well-known early Eocene fossil track locality in Utah appear to represent an otherwise unknown stilt-like bird, possibly referable to the Recurvirostridae. The bird that made these tracks had very long legs but relatively short toes and was probably somewhat smaller than modern stilts (Himantopus). There was a vestigial hind toe and the feet were webbed, but the webbing was reduced more than in Recurvirostra or Cladorhynchus, but not nearly as much as in Himantopus. This may constitute the oldest evidence yet found of a recurvirostid-like bird, although the family probably originated even earlier if it gave rise to flamingos (Phoenicopteridae), which were already in existence by the early and middle Eocene.