Point-count surveys of Black Terns (Chlidonias niger surinamensis) were conducted in Wisconsin from 1980 to 2011 to assess statewide population trends of this declining species. The survey program consisted of 19 roadside transects, each with 15 stops (N = 285 stops total), spread across 15 counties throughout the state. Surveys were conducted at the same sites each year during three periods (1980–1982, 1995–1997, 2009–2011) by observers who visited each site once during the breeding season (25 May to 24 June) and counted the number of Black Terns seen during a 5-min interval. Over the three survey periods, statistically significant changes in abundance occurred on 14 of the 19 transects, most of which either were linear or exponential declines; no significant increases were evident. Survey-wide, the population declined in abundance by nearly 70% over the past 30 years and site occupancy declined by a similar percentage. Complete extirpation was recorded on four transects. Nest counts in two intensive study areas were consistent with the declining trend indicated by the point-count surveys. Likely causes of the decline include continued loss and degradation of breeding habitat and low annual adult survival probability, the latter for which reasons currently are unknown. Protection of remaining breeding colonies and restoration of degraded wetlands are recommended conservation measures for this species in Wisconsin and elsewhere.

The status of Common Terns (Sterna hirundo) breeding in Canada is presented, with abundance trends in regions where data allow. Large (>12,000 pairs) concentrations of Common Terns nested in coastal Newfoundland, long the Gulf of St. Lawrence coast of New Brunswick, and in lakes Winnipeg, Winnipegosis and Manitoba in Manitoba. Nest numbers increased in the four provinces of Atlantic Canada ( 31%; 1973–2010), the Mingan Archipelago National Park Reserve Canada (MANPRC) in the Gulf of St. Lawrence ( 81%; 1986–2009) and possibly in Great Slave Lake ( 10%; 1988–2010). Nest numbers declined (-41%; 1976–2009) in Canadian waters of the North American Great Lakes. Based on recent census data (1999–2010), the number of Common Terns breeding in Canada was estimated at between 82,000–89,500 pairs, with possibly thousands of additional pairs elsewhere in Canada that have never been systematically censused: Manitoba, Saskatchewan, Alberta inland areas of eastern provinces and the boreal forest. Recommendations are that Common Terns be censused in these areas with protocols established for the Great Lakes and annual management be implemented at sites on the Great Lakes earlier identified as “high priority”. Adoption of these recommendations would achieve better understanding of national abundance trends and inform future consevation initiatives.

A decrease in wetland habitats throughout North America has caused a decline in populations of marsh birds. The objective of this study was to estimate population densities and abundances of secretive marsh birds in Iowa. Call-broadcast surveys were conducted in conjunction with distance sampling for eight species of marsh birds at wetlands in three regions of Iowa during 2009 and 2010. Regions were defined by observed microhabitat characteristics which also corresponded to physiographic regions. Region-specific density estimates were obtained using Program Distance for four species of marsh birds for which sufficient detections existed (Pied-billed Grebe [Podilymbus podiceps], Least Bittern [Ixobrychus exilis], Virginia Rail [Rallus limicola] and Sora [Porzana carolina]). The range of density estimates was 0.019 birds/ha (95% CI = 0.014-0.024) for Least Bittern to 0.12 birds/ha (95% CI = 0.11-0.14) for Pied-billed Grebe. Density estimates were highest in Region 2 for Pied-billed Grebe, Region 1 for Virginia Rail, and Region 3 for Sora. Least Bittern density was similar between Regions 1 and 2, but was 0.027 birds/ha lower in Region 3. The need to focus conservation efforts on areas of the state where large amounts of suitable habitat exist and marsh bird densities are highest is illustrated by the observed differences in species' densities across regions. Information on the current population status of marsh birds in Iowa and regions where conservation efforts can be directed are provided by these density estimates.

Wetland-dependent birds are considered to be at particularly high risk for negative climate change effects. Current and future distributions of American Bittern (Botaurus lentiginosus), American Coot (Fulica americana), Black Tern (Chlidonias niger), Pied-billed Grebe (Podilymbus podiceps) and Sora (Porzana carolina), five waterbird species common in the Prairie Pothole Region (PPR), were predicted using species distribution models (SDMs) in combination with climate data that projected a drier future for the PPR. Regional-scale SDMs were created for the U.S. PPR using breeding bird survey occurrence records for 1971–2000 and wetland and climate parameters. For each waterbird species, current distribution and four potential future distributions were predicted: all combinations of two Global Circulation Models and two emissions scenarios. Averaged for all five species, the ensemble range reduction was 64%. However, projected range losses for individual species varied widely with Sora and Black Tern projected to lose close to 100% and American Bittern 29% of their current range. Future distributions were also projected to a hypothetical landscape where wetlands were numerous and constant to highlight areas suitable as conservation reserves under a drier future climate. The ensemble model indicated that northeastern North Dakota and northern Minnesota would be the best areas for conservation reserves within the U.S. PPR under the modeled conditions.

Red-legged Cormorants (Phalacrocorax gaimardi) breed along a broad stretch of the Pacific coast and a section of the Argentinian coast on the Atlantic Ocean. To understand factors that might determine the breeding range along Argentina, physical and environmental characteristics of cliffed coastlines used by Red-legged Cormorants were compared with those not used. Red-legged Cormorant colonies were found in longer cliffed coastlines (mostly longer than 250 m) with shallow waters (median depth =12 m) and high sea productivity close to the coast (median chlorophyll a concentration = 4.4 mg/m3). Within the Red-legged Cormorants' breeding range the probability of occurrence of their colonies increased with the length of the cliffed coastline and decreased with the median sea depth around the colony. Mixed colonies were found in coastal areas with cliffs where the seawater close to shore was deeper (deeper than = 13 m). North of its distribution, sea productivity close to the coast was lower (median chlorophyll a concentration = 1.6 mg/m3) than within its distribution, and cliff faces were more exposed to the strong prevailing winds, which can blow eggs and chicks from their nests. South of its distribution, the climatic characteristics were more adverse to breeding success: higher precipitation, lower ambient temperature, and higher wind speed than within its distribution. At this scale of study (regional), new aspects of habitat structure of the Red-legged Cormorant, such as sea primary production, water depths and climatic features, were indentified. All these aspects could be affecting habitat selections by this species.

Data on the movement of immature Eurasian Spoonbills from the southern Pannonian Basin are presented for the first time and differences in migration patterns between the Atlantic and southern Pannonian breeding populations are identified. Movements of spoonbills from Western Europe are well known, but there is uncertainty about the movements of the eastern metapopulation, of which the southern Pannonian population forms part. Analyses were based on 707 resightings in Europe and North Africa of 272 color-ringed birds. The studied birds wintered in North Africa (predominantly Tunisia) or southern Italy (Sicily and Sardinia). Most birds used the central Mediterranean flyway, but crossed the Adriatic Sea at more northern latitudes than had previously been reported. With increase in age, the ratio of birds spending the breeding period at the wintering sites decreased (54.2% for second-year and 13.6% for third-year birds), while the ratio of those returning to the Pannonian breeding grounds increased (37.5% and 66.6% respectively). Older spoonbills arrived back at their natal areas earlier. Immature spoonbills from the southern Pannonian Basin population visited breeding colonies in Germany, confirming at least sporadic contacts between two metapopulations. Identification of migration routes and wintering areas is a major precondition for the conservation of the eastern metapopulation. Illegal hunting, tourism development on staging areas and lack of suitable feeding habitats along flyway have been identified as the most important threats.

Foraging trip duration of breeding seabirds is affected by characteristics of available feeding habitat in the marine environment, which may, in turn, generate inter-colony difference in the patterns of nest attendance. Here, nest attendance patterns and foraging areas of Streaked Shearwaters (Calonectris leucomelas) during their incubation period were examined using global location sensors. The study was conducted at Sangan (SI) and Mikura Islands (MI) in the northwestern Pacific, and Awa Island (AI) in the Japan Sea during 2006–2009. The duration of incubation shifts showed significant inter-colony difference, but no sex-related difference. Shearwaters from SI had shorter mean incubation shifts (5.6 days on average; range 3.0-8.0 days) than those from MI (7.2 days; range 4.8–10.7 days) and AI (6.9 days; range 6.0–9.7 days). During the incubation period, SI and MI shearwaters foraged in the northwestern Pacific's Kuroshio-Oyashio transition area, while shearwaters from AI mostly foraged in the Japan Sea. The Northwestern Pacific represents a high-productivity zone, and SI shearwaters appeared to forage in these waters, where foraging efficiency is potentially high, leading to shorter incubation shifts. Also, although MI shearwaters foraged in the northwestern Pacific, the distance between their colony and foraging areas was greater (645 km on average; range 546–756 km), compared to SI (272 km; range 244–297 km) and AI birds (228 km; range 75–518 km). In this study, inter-colony differences in incubation shift length of Streaked Shearwaters appeared to be related to differences in foraging areas associated with the local marine environment.

Previous Mottled Duck (Anas fulvigula) studies suggested that high female breeding season survival may be caused by low nesting effort, but few breeding season estimates of survival associated with nesting effort exist on the western Gulf Coast. Here, breeding season survival (N = 40) and breeding incidence (N = 39) were estimated for female Mottled Ducks on the upper Texas coast, 2006–2008. Females were fitted with backpack radio transmitters and visually relocated every 3–4 days. Weekly survival was estimated using the Known Fate procedure of program MARK with breeding incidence estimated as the annual proportion of females observed nesting or with broods. The top-ranked survival model included a body mass covariate and held weekly female survival constant across weeks and years (S_W = 0.986, SE = 0.006). When compared to survival across the entire year estimated from previous band recovery and age ratio analysis, survival rate during the breeding season did not differ. Breeding incidence was well below 100% in all years and highly variable among years (15%–63%). Breeding season survival and breeding incidence were similar to estimates obtained with implant transmitters from the mid-coast of Texas. The greatest breeding incidence for both studies occurred when drought indices indicated average environmental moisture during the breeding season. The observed combination of low breeding incidence and high breeding season survival support the hypothesis of a trade-off between the ecological cost of nesting effort and survival for Mottled Duck females. Habitat cues that trigger nesting are unknown and should be investigated.

Little has been documented on large (>250 g), water-associated birds in the north-eastern KwaZulu-Natal, South Africa, that nest colonially and rely on suitable sites for breeding. The purpose of this study was to highlight these species and the importance of nesting sites for their effective conservation management. From 1920–2010, there were 622 records of 27 of these species breeding at more than 48 sites. Five sites accounted for 65% of these breeding events, four at Lake St Lucia, highlighting its importance for bird conservation. Several sites were abandoned. However, two new sites have established more recently (Nsumo Pan, Mkhuze Game Reserve; Nyamithi Pan, Ndumo Game Reserve) that are important in terms of number of individuals as well as variety of species. Some species (Pink-backed Pelican Pelecanus rufescens, Grey-headed Gull Larus cirrocephalus, Caspian Tern Sterna caspia, Great-white Pelican P. onocrotalus and African Spoonbill Platalea alba) have bred regularly but have used only a few sites, mainly at Lake St Lucia. Two species (Glossy Ibis Plegadis falcinellus and Black Heron Egretta ardesiaca) have bred once only on Lane Island (1961) and in trees at the mouth of the Hluhluwe River (before 1964) respectively. Two colonial sites hosted 10-12 species while others (n = 8) only two. Twenty-one sites were used by only one species. Two species (Pink-backed Pelican and Yellow-billed Stork Mycteria ibis) nest nowhere else in South Africa on a regular basis. Recommendations for the ongoing monitoring and conservation of these colonially-nesting birds in the region, particularly in terms of securing these sites, are made.

Wood Stork (Mycteria americana) foraging flight studies at 20 colonies throughout the US range were reviewed to summarize foraging ranges and compared to 20, 25 and 30 km-wide regulatory buffers (“core foraging areas”) created to provide sufficient foraging habitats for breeding storks. Mean (per colony) direct distances to foraging sites ranged from 2.7 to 18.1 km, and between 75-100% of all follow flights went to foraging sites within 20 km of their colony. Overall, reviewed follow flight data suggested that the 20-km buffer would be sufficient for all breeding colonies in the US. However, such a reduction is not supported at this time due to limited recent data for certain regions of the Wood Stork breeding range (e.g. central and southern Florida). Additional, preferably multi-year, foraging habitat use studies are needed to fill data gaps for these areas to better assess the validity of the CFA buffers.

Winter foraging ecology of Marbled Godwit (Limosa fedoa), Long-billed Curlew (Numenius americanus), Whimbrel (Numenius phaeopus) and Willet (Tringa semipalmata) was studied in relation to conspecific density at Estero de Urías, a tropical coastal lagoon in northwestern Mexico. Specifically, the effect of ecological factors in relation to individual prey capture rates for Marbled Godwits and both Numenius spp. was examined. There was a consistent, inverse relationship between conspecific density and foraging activity, but the slope differed among species. The inverse relationship suggests that conspecific density was an important determinant of individual foraging behavior and habitat use across species. For Marbled Godwits, prey capture rate was positively correlated with conspecific density and water depth, but negatively correlated with tidal height, at least during spring tides. In contrast, for both Numenius spp., prey capture rate was significantly higher for territorial birds and tactile foragers, in the case of Curlews, but was independent of tidal conditions. When neap tides resulted in reduced foraging time budget, Marbled Godwits increased prey capture rate, but Numenius spp., did not. Differences in foraging mode, availability of preferred prey in relation to water depth, as well as handling time of prey, could drive these distinct patterns between godwits and both Numenius spp. These results support suggestions that the increased conspecific density during periods of neap tides might explain the reduced prey capture rate of individuals with less competitive ability, especially within large shorebirds showing a sparse foraging distribution.

Behavior by a foraging seabird during the breeding season can be examined by analyzing time invested throughout the foraging route to determine the presence of Area-Restricted Search (ARS) as well as other characteristics related to the shape of the foraging path and activity (flying, resting or diving). Forty-six Imperial Cormorants (Phalacrocorax atriceps), 18 males and 28 females breeding at Punta León, Argentina (43°04′S; 64°2′W), were fitted with GPS loggers recording one foraging trip (sampling interval: 1 second) in 2004, 2005, 2007 and 2008. Trip duration was longer, on average, for females (6.3 ± 1.9 h) than males (5.3 ± 1.6 h) (Mann-Whitney U test z 1,45 = 2.23, P = 0.026), but year had no significant effect on any of the path characteristics. ARS was detected in 43 individuals, 22 of which made smaller-scaled searches nested within larger ARS areas. Search scale was not correlated to maximum distance reached and did not differ between sexes nor years. Cluster analysis separated four types of behavior: short direct return trips (N = 7), long direct return trips (N = 31), random flight searches (N = 6) and loops (N = 2), with each behavioral type present in both sexes. Behavioral variability within a population may be due to differences in targeted prey type and spatio-temporal stability during the season, as well as to individual physiological constraints and life-history traits linked to how individuals search for food at sea.

The application of stable-isotope analysis (SIA) in ecology has increased exponentially in the last 20 years. As with any novel field of inquiry, there has been inconsistent (and sometimes confusing) use of terminology and great variation in how the results of SIA are presented in the scientific literature. Recently, guidelines and recommendations for the consistent use of terminology, the expression of results, and presentation of symbols were prepared and published at the request of the Commission on Isotopic Abundances and Atomic Weights (CIAAW) of the International Union of Pure and Applied Chemistry (IUPAC). Here, key components of the CIAAW recommendations pertinent to ecologists are summarized, along with suggestions for best practices in reporting results of SIA not covered by the CIAAW guidelines. A set of universally adopted and consistently used terminology and practices will minimize ambiguity, especially in the overlap of different fields, such as analytical chemistry and ecology. The Erratum for this article can be found in Waterbirds 35(3).

Determining the sex of Crab Plovers (Dromas ardeola) based on morphology has, hitherto, proven difficult. Here, six morphological traits (head-bill length, bill length, bill depth, wing chord, tarsus length and weight) of 39 molecularly or behaviorally sexed breeding Crab Plovers were compared in order to find a reliable morphometric way to determine their sex. Males were significantly larger than females in all traits, except tarsus length, and especially in traits related to head and bill size, where males were 6.8 to 11.4% larger than females. Discriminant Function Analysis correctly classified 97.4% of birds using only bill depth and bill length, providing an efficient tool for sexing Crab Plovers in the hand.

Cannibalism has never been documented in any species of cormorant. While conducting a study on the Socotra Cormorant (Phalacrocorax nigrogularis) colony of Siniya Island, Umm Al Quwain, United Arab Emirates, several instances of heterocannibalism were observed and photographed during October–December 2011. Older fledgling chicks were observed consuming younger altricial chicks. Such behavior may be due to a period of forced starvation, caused by abandonment by the parents in the third creching stage. The frequency of observed events suggests that this behavior may be common in Socotra Cormorants and should be investigated to determine possible causes and effects on the conservation of the species.

Several methods exist to capture ground-nesting birds, yet questions remain concerning their effectiveness, cost and safety. An experiment was conducted comparing traps commonly used to capture ground-nesting shorebirds. Data were collected on Snowy Plovers (Charadrius nivosus) nesting at Great Salt Lake, Utah during the 2009 breeding season. The three most common traps used to capture nesting Snowy Plovers (spring trap, walk-in funnel trap, leg-hold noose mats) were compared in the time required to use the trap (e.g. time to install at nest), capture success and construction costs. These results indicated that the funnel trap had the lowest total time at the nest (P < 0.01) and per trapping attempt, highest capture rate, fewest failed set up attempts, low disturbance to the nest site and was the least expensive to build. Based on these findings, the funnel trap should allow avian researchers to maximize their time, resources and efforts when trapping ground-nesting shorebirds.

In the United States, the Snail Kite (Rostrhamus sociabilis plumbeus) is a federally endangered species and restricted to the wetlands of south-central Florida where the current population numbers less than 1,500. The Snail Kite is an extreme dietary specialist, previously feeding almost exclusively on one species of snail, the Florida Apple Snail (Pomacea paludosa). Within the past decade, an exotic species of apple snail, the Island Apple Snail (Pomacea insularum), has become established on lakes in central Florida. Island Apple Snails are larger than the native Florida Apple Snails, and Snail Kites handle the exotic snails less efficiently. Juvenile Snail Kites, in particular, have lower daily energy balances while feeding on Island Apple Snails. An inexpensive, easy-to-construct platform was developed that would provide Snail Kites with a flat, stable surface on which to extract snails. The platform has the potential to reduce the difficulties Snail Kites experience when handling exotic snails, and may benefit the Snail Kite population as a whole. Initial observations indicate that Snail Kites use the platforms frequently, and snails extracted at the platforms are larger than snails extracted at other perches.