Piping Plovers (Charadrius melodus) are primarily monogamous birds that usually raise only one brood per season, but rare instances of double brooding have been documented. Piping Plovers breeding in the northern Great Plains, USA were studied in two locations: the Missouri River near the Gavins Point Dam (2005– 2013) and the lower Platte River (2008–2013). There were 25 confirmed instances of double brooding on the Missouri River across the 9-year duration of the study. There were no instances of double brooding observed locally on the lower Platte River. However, in 2013, two female Piping Plovers successfully hatched eggs and fledged chicks from nests on the lower Platte River and later were observed nesting for a second time on the Missouri River. Factors predicted to increase the frequency of double brooding are: early nest initiation, male biased sex ratio, age of breeding adults, and decreased nesting density. Our results indicate density is an important factor that accounts for some of the difference in the proportion of double brooding on the Missouri River compared to the lower Platte River. It is likely a combination of factors is responsible for this behavior, previously thought to be rare, in Piping Plovers.

Foraging habitat use by colonial waterbirds breeding in New York Harbor was examined to identify resources that were particularly important for the provisioning of young. Stable isotope values of carbon, nitrogen, and sulfur were measured in nestling waterbird feathers to determine the habitat type (ranging from marine to freshwater and anthropogenic) in which adults primarily foraged. Six species were investigated: Black-crowned Night-Herons (Nycticorax nycticorax), Great Egrets (Ardea alba), Glossy Ibises (Plegadis falcinellus), Double-crested Cormorants (Phalacrocorax auritus), Great Black-backed Gulls (Larus marinus), and Herring Gulls (L. argentatus). Waterbird populations exhibited both inter- and intra-specific variation in stable isotope values (P < 0.001), indicating variation in foraging habitat use among focal species across the estuary. Therefore, depending on the species-and region-specific conservation goal, management strategies would potentially need to target very different foraging habitats for protection and remediation. For instance, habitat use by Double-crested Cormorants closely reflected available habitat near nesting colonies, while Glossy Ibises used primarily freshwater resources at one colony and marine resources at another, despite the fact that both colonies were located in marine environments. Great Egrets and Double-crested Cormorants both showed significant regional variation in isotopic niche size, and both species of gulls (considered to be generalist scavengers) were found to have isotopic niche sizes reflecting a specialist diet. Stable isotope analysis of nestling feathers provided novel information about the foraging resources that were most important to waterbirds in regions across the harbor.

This paper examines the reasons behind the large population explosion of the Herring Gull (Larus argentatus) in Great Britain, which started about 1900, continued for 60–70 years and was then followed by a decline in numbers. The increase has often been associated with food obtained at landfills, but it is better explained by other causes because such sites were not used for feeding until the increase had been in progress for 50 years and for less than 20 years before gull numbers started to decline. Further, the flock and frenzy method of feeding used by Herring Gulls at landfills is not well adapted for the successful exploitation of this food source, and the frequency of use has often been exaggerated. The historic increase in Herring Gulls starting in about 1900 should be attributed to protection and then food acquired from the marine environment, including fishing offal, and increased feeding on agricultural land. Culling has contributed more to the recent decline of the population than has been previously assessed because of secrecy and lack of detail about many such events. Feeding at landfills may have been detrimental to the Herring Gull population owing to increased mortality from botulism acquired there. It is concluded that culling and botulism both contributed appreciably to the end of the population explosion that occurred around 1970, and to the subsequent decline of the Herring Gull in Great Britain. The increase and continued spread of Herring Gulls nesting in urban areas in Great Britain cannot be explained by food obtained within the towns. Observations that, in some areas, most of these gulls rarely fed at landfill sites, and so avoided botulism, may account for their continued increase in urban areas.

The occurrence and nesting phenology of Ardeidae species and other wading birds were documented from 2009–2013 in the Bahía Kino bioregion of western Sonora, México. Two active colonies were surveyed: in a mangrove (Avicennia germinans; Rhizophora mangle) estuary and on a nearshore desert island. Thirteen species of nesting wading birds were recorded, 11 of which are year-round residents and two occurring only during the breeding season; two additional species were documented only in migration. The most abundant species was the Snowy Egret (Egretta thula), which had a peak of 234 nests in 2012. Of particular conservation interest is the Reddish Egret (E. rufescens), which had a peak of 149 nests in 2012. Potential prey of wading birds in the estuary was also sampled, with special focus on brachyuran crabs, which constitute the main prey items of the Yellow-crowned Night-Heron (Nyctanassa violacea). The rapid development of the region, and especially the establishment of largescale mariculture operations along Estero Santa Cruz, has the potential to impact local wading bird populations, and thus an understanding of wading bird diversity, abundance and habitat use may prove critical to inform future management and conservation initiatives.

Glossy Ibis (Plegadis falcinellus) populations have declined over much of their global range over the past 30 years and in Australia numbers fell by almost 40% between 1977–1981 and 1998–2002. In Australia, loss of wetland area and quality in relation to river regulation for irrigated agriculture are the main suggested causes. The species' diet has been quantified in many areas, but there have been no detailed studies of its foraging habitat requirements upon which to base conservation measures. This study quantified foraging habitat selection at Fivebough Swamp, New South Wales, an internationally important feeding and roosting site for non-breeding Glossy Ibis. Typical of many floodplain wetlands in southeastern Australia, Fivebough Swamp is temporary, flooding during the wet season and drying during the hot summer. Glossy Ibis showed a strong preference for feeding in areas of water couch grass (Paspalum distichum) less than 10 cm tall interspersed among open water, and avoidance of areas dominated by bulrush (Typha spp.), common spike rush (Eleocharis acuta) and open non-vegetated water. Water couch grass supported significantly higher densities of aquatic macroinvertebrate prey for Glossy Ibis than did the other habitats, including Gastrodpoda, Hemiptera and Coleoptera. Water couch grass can form dense contiguous mats of up to 50 cm in height above water level, which would be too high and dense for Glossy Ibis to probe through. In the absence of natural herbivores, livestock grazing by cattle (Bos taurus) at low stocking rates can be used to suppress this growth and maintain suitable conditions for Glossy Ibis.

Bird use of diked and undiked Michigan coastal wetlands (n = 17) was studied on Lake St. Clair and Lake Huron during late July to mid-October, 2005–2007. Relative abundance and diversity were compared via aerial (n = 9) and ground (n= 155) surveys and wetland characteristics were measured. Species richness and similarity indices suggested analogous bird use, but multivariate analyses indicated significant separation in diked and undiked bird assemblages. Wood Duck (Aix sponsa), Great Blue Heron (Ardea herodias), and Wilson's Snipe (Gallinago delicata) were more abundant on diked sites, whereas dabbling ducks combined, Mallard (Anas platyrhynchos), American Black Duck (A. rubripes), gulls (Laridae), Forster's Tern (Sterna forsteri), and Greater Yellowlegs (Tringa melanoleuca) were more abundant on undiked wetlands. Wetland characteristics also differed. Diked sites were primarily cattail (Typha spp.) marshes interspersed with small open-water areas containing aquatic plants. Undiked sites had larger openings fringed with bulrushes (Schoenoplectus spp.), fewer aquatic plants, and direct lake connections. Periodic drawdowns of diked wetlands could encourage greater plant species and structural diversity, making them more attractive to dabbling ducks. However, risk of common reed (Phragmites australis) expansion is high in the study areas, thus its control may be necessary before enhanced management can occur.

Apicomplexan blood parasites Plasmodium and Haemoproteus (together termed “Avian malaria”) and Leucocytozoon are widespread, diverse vector-transmitted blood parasites of birds, and conditions associated with colonial nesting in herons (Ardeidae) and other waterbirds appear perfect for their transmission. Despite studies in other locations reporting high prevalence of parasites in juvenile herons, juvenile Little Egrets (Egretta garzetta) previously tested in the Camargue, Southern France, had a total absence of malaria parasites. This study tested the hypotheses that this absence was due to insufficient sensitivity of the tests of infection; an absence of infective vectors; or testing birds too early in their lives. Blood was sampled from juveniles of four species shortly before fledging: Little Egret (n = 40), Cattle Egret (Bubulcus ibis; n = 40), Black-crowned Night-Heron (Nycticorax nycticorax, n = 40), and Squacco Heron (Ardeola ralloides; n = 40). Sensitive nested-Polymerase Chain Reaction was used to test for the presence of parasites in both birds and host-seeking female mosquitoes captured around the colonies. No malaria infection was found of in any of the heron species. Four different lineages of Plasmodium were detected in pooled samples of female Culex pipiens mosquitoes, including two in potentially infective mosquitoes. These results confirm that the absence of malaria parasites previously demonstrated in Little Egret is not due to methodological limitations. Although the prevalence of infection in mosquitoes was low, conditions within the colonies were suitable for transmission of Plasmodium. These colonial heron species may have evolved strategies for resisting malaria infection through physiological or behavioral mechanisms.

The reproductive biology of the Striated Heron (Butorides striata) was studied in the lagoon of the Reserve of the Universidad Nacional del Litoral, Santa Fe, Argentina, during two breeding seasons: September 2012–February 2013 (n = 77) and September 2013–March 2014 (n = 125). All nests (n = 202) were built on waxy-leaf nightshade (Solanum glaucophyllum) at 0.99 ± 0.27 m above water level. The incubation period was 20–23 (21.71 ± 1.57) days; laying and hatching took place on successive days. An average of 2.63 ± 0.60 (Range = 2–4) opaque pale blue eggs were recorded per nest. Length, width and weight of eggs did not differ between seasons. Double (n = 43) and triple (n = 47) broods were recorded. A total of 631 eggs were monitored; no differences were detected in breeding, hatching, nesting, or fledging success between seasons. The time spent by chicks in the nest was 14.6 ± 2.16 days, and the average number of chicks per nest was 2.15 ± 0.55. Age-specific mortality rate for eggs was 22% and 38% and for chicks 47% and 35% for the first and second seasons, respectively. Sixty-one percent of nest failures were related to the disappearance of eggs or chicks from the nests, possibly due to predation or climatic factors.

The Reddish Egret (Egretta rufescens) is a species of conservation concern on an international scale, yet relatively little is known about its life history strategies and demographics. To estimate post-fledging survival and examine dispersal patterns/rates, Reddish Egrets (n = 30 fledglings) were monitored and marked with VHF radio transmitters in the Laguna Madre, Texas, in 2006. Overall daily survival rate was 0.78 (SE = 0.11). Reddish Egrets dispersed from their natal colony at 12–15 weeks after hatching, and the average distance traveled in the Laguna Madre ranged from 0 to 488 km. These results help fill a knowledge gap during this little-known time period of the Reddish Egret. Furthermore, these results show that the Laguna Madre is an important system during this critical stage of development as many of the juveniles remained in this lagoon through the duration of our 6-month study.

The Cay Sal Bank in The Bahamas is one of the Caribbean region's most important areas for breeding seabirds, but the colonies previously lacked solid estimates. This paper describes results of four visits between 2010 and 2012. The Santaren Channel, used to transit to and from Cay Sal Bank, contained high numbers (6.1 ± 0.4 birds per km²) of seabirds. The Cay Say Bank has at least 117 detectable islands with 484 ha of land area; the most numerous colony was at Elbow Cay (23 ha). Audubon's Shearwaters (Puffinus lherminieri) were breeding at 97 pairs per ha (total: 2,200; 95% CI = 1,650–2,800 pairs), Sooty Terns (Onychoprion fuscatus) at 382 pairs per ha (total: 8,800; 95% CI = 6,900–10,700 pairs), Bridled Terns (Onychoprion anaethetus) at 38 pairs per km coastline (5,829 m coastline; total: 220; 95% CI = 145–295 pairs) and Brown Noddies (Anous stolidus) at 72 pairs per ha (total: 1,609; 95% CI = 1,070–2,250 pairs). The population of Audubon's Shearwaters is among the largest in the world while populations of the other species are regionally significant. Roughly 420 ha (87% of the available land) were visited; however, many of the smaller cays (43 islands with 30 ha of habitat) have still not been surveyed. Seabirds were present in low densities (0.3–20 total pairs per ha) on the other large islands, all of which contain populations of introduced black (Rattus rattus) or Norway (R. norveigicus) rats. These visits provide the first repeatable surveys of breeding seabirds at Cay Sal Bank.

Little is known about sublethal effects on birds of low level exposure to oil. White blood cell parameters (total leukocyte counts and/or differentials) were measured in blood samples from Common Terns (Sterna hirundo; n = 71) exposed to low levels of oil from an oil spill in Buzzards Bay, Massachusetts, in 2003. Data from Common Terns (n = 16) sampled at the same site in a non-spill year were used for reference. Total leukocytes and lymphocytes were severely depressed when individuals were first sampled, 14–20 days after the spill, and returned to near to or above reference levels by day 39. Heterophils and heterophil/lymphocyte ratios were markedly elevated 14–20 days after the spill, and returned to below reference levels by day 39. These changes were closely parallel to changes in hematocrit in the same birds, but hematocrits were not correlated with white blood cell parameters, suggesting that mechanisms of action were different. The combination of immune suppression and anemia during the physiologically demanding period prior to and during egg-laying is likely to have caused adverse effects on reproduction.

Leg-loop harnesses for the attachment of telemetry devices have been used for over two decades in terrestrial bird research. Recently, the technique has been extended to waterbird applications. An equation exists for predicting the dimensions of correctly fitting leg-loop harnesses in terrestrial bird research. This equation appears robust to the varied life histories of terrestrial birds. Yet, the applicability of this equation for waterbird research has not been tested. Here, we present the dimensions of leg-loop harnesses fitted to Lesser Frigatebirds (Fregata ariel), a sexually dimorphic seabird species. For both sexes, measured harness spans were shorter than those predicted by the terrestrial bird equation. Additionally, leg-loop harnesses trialed on Brown (Sula leucogaster) and Masked (S. dactylatra) boobies were unsuitable and hence unsuccessful. Morphological and behavioral features of species suited to leg-loop harness attachment are identified.

A Sandwich Tern (Thalasseus sandvicensis sandvicensis) banded as a chick in 2002 at Coquet Island off the northeast coast of Great Britain was observed at two locations on Cape Cod, Massachusetts, USA, in August and September 2013. This is the first record of a banded Sandwich Tern from the United Kingdom being observed in the United States.

Forster's Terns (Sterna forsteri) breed mainly in central Canada and the north-central USA, and along both coasts of North America. In Mexico, only five nesting colonies were known prior to this study and all are coastal, three from Baja California, one from Colima on the Pacific coast, and one from Tamaulipas on the Gulf of Mexico. In 2014, a new inland colony was found at the Lake of Texcoco, east of Mexico City, Mexico. Eight nests that were located on small islets 400 m away from shore were monitored from April to June 2014. Almost 90% of the eggs (n = 16) were lost by flooding, and only two chicks hatched. One chick died and the other survived to fledging, and at 25 days old it dispersed more than 3 km from the colony. This nesting colony at the Lake of Texcoco represents a new breeding site of Forster's Tern in Mexico, the first breeding record in an interior wetland of Mexico, and a southward expansion of the known breeding range for this species. These observations reinforce the importance of the Lake of Texcoco for breeding waterbirds in the Valley of Mexico.