Wetlands in the Playa Lakes Region of Texas are important habitats for North American wintering waterfowl and migrant shorebirds. However, shorebird breeding biology has been overlooked in characterizing the region’s ecological importance. In 1998 and 1999, American Avocet (Recurvirostra americana), Black-necked Stilt (Himantopus mexicanus), Killdeer (Charadrius vociferous), and Snowy Plover (C. alexandrinus) breeding ecology were studied in playas, saline lakes, and riparian wetlands in the Playa Lakes Region of Texas. Chronology of nest initiation, clutch sizes, and hatching success for 298 Snowy Plover, 111 American Avocet, 43 Killdeer, and 26 Black-necked Stilt clutches were measured. All four species nested in saline lakes, American Avocet and Killdeer also nested in playas, and Snowy Plover nested on riparian wetlands. American Avocet had higher hatching success in 1999 (52%) than 1998 (8%), because of more suitable hydrological conditions and lower predation. Hatching success was higher in 1998 than 1999 for Killdeer (1998, 63%; 1999, 21%) and Snowy Plover (1998, 47%; 1999, 33%) due to failures caused by flooding and hail in 1999. In other regions, clutch predation limits shorebird productivity, but hatching success in the Playa Lakes Region appears to be limited by unpredictable precipitation patterns and wetland hydroperiod. As such, breeding shorebird conservation and management should focus upon maintaining wetland hydrological integrity.

In 1995, parental activities of Wood Storks (Mycteria americana) were monitored in three coastal colonies during a series of 24-h long observation periods to document attendance, foraging, and other activities in relation to time of day, tide level, and breeding stage. During 5,400 nest-hours of observations, nest attendance declined and feeding rates increased with nestling developmental stage. Although some feeding arrivals occurred during darkness, the great majority of arrivals (including feeding) occurred during daylight periods. Mean times of return from feeding trips varied significantly among colonies and nestling developmental stages. Feeding arrivals were linked to tides, suggesting that most foraging occurred during the preceding low tide period. Inter-colony variation in foraging arrival times and interactions with tides were likely associated with differences in proximity to foraging sites and availability of both tidal and non-tidal (freshwater) foraging habitats.

The Caribbean Coot (Fulica caribaea) is endemic to the Caribbean region where it is uncommon to rare. Little is known about its breeding biology. From museum specimens, archives and correspondence, we document 134 records for Aruba, Curaçao and Bonaire, Netherlands Antilles, from the years 1955-2004, and map their distribution. The islands are arid and rainfall can be unpredictable but with the establishment of permanent freshwater ponds since the 1970s, the Caribbean Coot appears to have become more common. We recorded 68 cases of breeding for the three islands. Although breeding can occur in almost any month, there is a clear preponderance for birds to breed in the first few calendar months of the year, approximately three months after the annual peak in rainfall.

American Oystercatcher (Haematopus palliatus) numbers along the east coast of the United States are declining in some areas and expanding in others. Researchers have suggested that movement from traditional barrier beach habitats to novel inland habitats and coastal marshes may explain some of these changes, but few studies have documented oystercatcher reproductive success in non-traditional habitats. This study compares the reproductive success of the American Oystercatcher on three river islands in the lower Cape Fear River of North Carolina with that of birds nesting on barrier island beach habitat of Cape Lookout National Seashore. There were 17.6 times more oystercatcher breeding pairs per kilometer on the river island habitat than barrier beach habitat. The Mayfield estimate of daily nest content survival was 0.97 (S.E. ± 0.0039) on river islands, significantly higher than 0.92 (S.E. ± 0.0059) on barrier islands. The primary identifiable cause of nest failure on the river islands was flooding while the main cause of nest failure on the barrier islands was mammalian predation. Fledging success was equally low at both study sites. Only 0.19 chicks fledged per pair in 2002, and 0.21 chicks fledged per pair in 2003 on the river islands and 0.14 chicks fledged per pair in 2002 and 0.20 chicks fledged per pair in 2003 on the barrier islands. Many questions are still unanswered and more research is needed to fully understand the causes of chick mortality and the functional significance of non-traditional nesting habitats for the American Oystercatcher in the eastern United States.

Most studies of the kleptoparasitic behavior of gulls have involved intermediate-sized species. This study examined the kleptoparasitic relationships between the Pied Oystercatcher (Haematopus longirostris) feeding on Surf Clams (Mactra rufescens) and a large gull species, the Pacific Gull (Larus pacificus) in the swash zone of an ocean beach in Tasmania, Australia. Oystercatchers caught Surf Clams buried in sand using visual cues when the clams were covered by shallow water at low tide. There was no selection for clam size, possibly because they were unable to assess size before capture. Shells were not broken by hammering, but by forcing the bill into and between the valves. Handling time was prolonged and was significantly related to shell length. The profitability of clams (ash-free dry mass of flesh ingested per second of handling time) was independent of shell length. Pacific Gulls stole 8% of all clams taken by the oystercatchers. The mean length and ash-free dry mass of clams stolen (54.3 ± 0.64 mm; 8.14 ± 1.5 mg, N = 51) were significantly greater than that of all clams (46.8 ± 0.65 mm; 5.10 ± 0.3 mg, N = 98) caught by the oystercatchers. The oystercatchers had frequent rest periods between bouts of foraging, suggesting they were able to capture and ingest clams faster than they could digest them and experienced a digestive bottleneck. Losses to Pacific Gulls probably had no significant effect on the oystercatchers as they had adequate feeding time available to compensate.

Although storm petrels are regarded as surface feeders, there is evidence that some species can dive. However, their diving performances and the importance of diving in their foraging tactics have never been accurately assessed. This study aimed to determine the occurrence of diving behavior and the diving ability of the Madeiran Storm Petrel (Oceanodroma castro) using maximum depth gauges. Out of 29 gauges deployed, 18 were recovered and 16 were readable. All the birds had dived, the maximum depths recorded averaging 0.85 m, and diving is part of the typical foraging behavior of the Madeiran Storm Petrel. This study provides a new insight on storm petrel foraging strategies.

We report on the incidence of kleptoparasites and the host avoidance responses in a colony of the Sandwich Tern (Sterna sandvicensis) at l’Albufera de Valencia, eastern Spain, in 2004. Apart from conspecifics, five species were kleptoparasites of breeding Sandwich Terns, particularly Black-headed Gull (Larus ridibundus) and Slender-billed Gull (L. genei). Avian kleptoparasites attacked 24% of the Sandwich Terns returning to the colony with fish (N = 659) and robbed 5.3% of them. Most terns (85%) delivered their prey to a mate or chick. Fish carried by terns were mainly Clupeiformes species (96%). Prey size declined significantly as the season progressed. The probability of attack increased significantly with fish size and declined significantly as the season progressed. Most attacks were on terns as they landed to deliver their prey. Overall success rate of attacks was 12.5% and were mostly performed by single birds. The time that the terns spent flying before landing to deliver prey increased with the size of carried fish.

During 1995, the relationship between the nesting chronology of the Least Tern (Sterna antillarum) and the near-shore abundance of fish was examined at La Purinera, Sonora, the site of one of the largest known Least Tern colonies in northwest Mexico. Fish abundance was measured adjacent to the shoreline during early mornings using a beach seine net, and the sampling periods corresponded to different phases of the Least Tern’s annual cycle. During this year, the nesting season (April to July) coincided with peak prey fish abundance, and peak hatching of tern eggs (early July) coincided with the greatest abundance of fish of adequate size for chicks. Departure of the terns from the area coincided with a marked reduction in suitable food in September. Collections of fish dropped and left uneaten by Least Terns in the colony contained five species, which were also present in the fish samples obtained with the beach seine net. The observations on foraging adult Least Terns and the collections of fish dropped in the colony suggested that the terns were preying mainly upon silversides (Leuresthes sardina, Colpichthys regis) and anchovies (Anchoa spp.). Terns foraged mainly on the bay side of the barrier beach where fish were more abundant. The results support the idea that seabird breeding and food abundance or availability coincide at the time of maximum need, when parents feed rapidly growing chicks.

The Black Tern (Chlidonias niger) nests in freshwater wetlands that are prone to water level fluctuations, and nest losses to flooding are common. We examined temporal patterns in water levels at six sites with Black Tern colonies in Maine and determined probabilities of flood events and associated nest loss at Douglas Pond, the location of the largest breeding colony. Daily precipitation data from weather stations and water flow data from a flow gauge below Douglas Pond were obtained for 1960-1999. Information on nest losses from three floods at Douglas Pond in 1997-1999 were used to characterize small (6% nest loss), medium (56% nest loss) and large (94% nest loss) flood events, and we calculated probabilities of these three levels of flooding occurring at Douglas Pond using historic water levels data. Water levels generally decreased gradually during the nesting season at colony sites, except at Douglas Pond where water levels fluctuated substantially in response to rain events. Annual probabilities of small, medium, and large flood events were 68%, 35%, and 13% for nests initiated during 23 May-12 July, with similar probabilities for early (23 May-12 June) and late (13 June-12 July) periods. An index of potential nest loss indicated that medium floods at Douglas Pond had the greatest potential effect on nest success because they occurred relatively frequently and inundated large proportions of nests. Nest losses at other colonies were estimated to be approximately 30% of those at Douglas Pond. Nest losses to flooding appear to be common for the Black Tern in Maine and related to spring precipitation patterns, but ultimate effects on breeding productivity are uncertain.

Nocturnal incubating and brooding behavior of the Black Tern (Chlidonias niger) was studied at two colonies in successive years in The Netherlands. In late evening and early morning, nests were checked regularly for female or male nest attendance until or from complete darkness. During daytime females incubated eggs 60% of the time. At night, males took over completely, while females spent the night at a communal roost more than three km away from the breeding colonies. Few females stayed with their downy young at night and more females brooded young, as chicks became older. The total parental breeding investment (day and night) was equal (51% for males), but with higher nocturnal investment by males (79%). From six days after hatching, chicks were left unattended at night. The difference between male and female nocturnal investment might be explained by the preference for self-survival instead of clutch and brood survival. Males probably have greater interest in clutch survival than females, as they are not certain to maintain the pair bond after egg loss within or between seasons. Due to increased human disturbance in Dutch wetlands, chicks now leave their nests permanently more often. This may lead to more frequent cases of chick starvation, as sometimes the young cannot find alternative resting sites.

A number of factors were identified as causes of mortality in 254 (59%) of 431 sea ducks submitted for necropsy at the USGS-National Wildlife Health Center, Madison, Wisconsin from 1975 until 2003. Bacteria causing large outbreaks of mortality were Pasteurella multocida and Clostridium botulinum Type E. Starvation was responsible for large mortality events as well as sporadic deaths of individuals. Lead toxicity, gunshot and exposure to petroleum were important anthropogenic factors. Other factors that caused mortality were avian pox virus, bacteria (Clostridium botulinum Type C, Riemerella anatipestifer and Clostridium perfringens), fungi (Aspergillus fumigatus and an unidentified fungus), protozoans (unidentified coccidia), nematodes (Eustrongylides spp.), trematodes (Sphaeridiotrema globulus and Schistosoma spp.), acanthocephalans (Polymorphus spp.), predation, cyanide and trauma (probably due to collisions). There were also a number of novel infectious organisms in free-living sea ducks in North America, which were incidental to the death, including avipoxvirus and reovirus, bacteria Mycobacterium avium, protozoans Sarcocystis sp. and nematodes Streptocara sp. Apart from anthropogenic factors, the other important mortality factors listed here have not been studied as possible causes for the decline of sea ducks in North America.

Ducks are unusual in that males of many species acquire brightly pigmented plumages in autumn rather than in spring. This has led to confusion in defining molts and plumages, using both traditional European terminology and that proposed by Humphrey and Parkes (1959). To investigate molt patterns in waterfowl relative to molt and plumage nomenclature, 2,227 specimens of ducks and geese were examined. Both the “first prebasic” (“post-juvenile” using traditional European terminology) and the “definitive prebasic” (“adult post-breeding”) body molts in most ducks, the latter producing the cryptic spring (female) and summer (male) plumages preceding the wing molt, are considerably more variable and less extensive than reported. By contrast, the “definitive prealternate” (“adult pre-breeding”) body molt of most ducks, which follows the wing molt and produces the brightly colored plumages of males, is complete or virtually so. Based upon presumed homologies with the molts of geese, the wing molt and ensuing complete body molt of ducks are better considered the prebasic rather than the prealternate molt and, thus, the bright feathering of male ducks should be considered the basic plumage. The incomplete and ephemeral cryptic plumages, attained by some ducks in spring and summer, may have evolved more recently in species that benefit from camouflage at this time, and should be considered alternate plumages. The molts and plumages of the adult Ruddy Duck (Oxyura jamaicensis) appear to be homologous with those of other Anatine ducks, with a slight temporal shift in the hormonal cycles that control pigment deposition (as opposed to differences in molt patterns) explaining the differences in plumage-coloration patterns in males. Because feather pigment-deposition patterns are controlled by various factors related to seasonal and reproductive phenomena, which differ considerably both among and within taxa, plumage color should not be a critical factor in attempts to define homologous molts and plumages.

Models of the Snowy Egret (Egretta thula), that use the tendency of wild birds to join foraging aggregations, were used in manipulative experiments to test the ability of wild individuals to use environmental and social information indicative of patch quality, including pool depth, prey accessibility, prey density, and prey exploitation, when choosing foraging patches. Snowy Egrets, but not some other aggregation species, preferred shallow (<20 cm) compared to deep (>40 cm) pools, perhaps because they could wade throughout the shallow pools, disturbing fish prey and making them more accessible for capture. Snowy Egrets responded to an artificial increase in fish density by visiting prey-enhanced pools more than pools with most fish removed or unmanipulated pools. Snowy Egrets also responded to a decrease in prey density resulting from recent exploitation by aggregations by visiting these pools less than unmanipulated pools. These results indicate that, in addition to the presence of other individuals, Snowy Egrets used discernible pool characteristics such as depth, as well as the availability and density of prey when choosing patches in which to forage.

Foraging by Grey Herons (Ardea cinerea) on fish regurgitated by Great Cormorants (Phalacrocorax carbo) was investigated in large mixed colony (ca. 10,000 pairs of cormorants and 700 pairs of herons) at Kąty Rybackie (north Poland). Experiments with displaying fish in different parts of the mixed and monospecific colonies were carried out. Herons took fish only within the area of mixed nests. Herons foraged on regurgitated fish during the whole breeding season but most intensively (up to 18% of all birds) in the fledging period. The main foraging area of herons (the Vistula Lagoon) has abundant food and is situated close to the colony. The fish regurgitated by cormorants constituted an important source of food for fledglings in the critical period after leaving the nest and was an alternative or supplementary food for adult birds during a period of bad weather. Extra food available in the colony could be responsible for high breeding success of the herons in the mixed colony at Kąty Rybackie.

Ground-truthing surveys were conducted in conjunction with a statewide aerial survey of Florida wading bird colonies to evaluate the efficacy of the aerial technique. Five species, Brown Pelican (Pelecanus occidentalis), Double-crested Cormorant (Phalacrocorax auritus), Anhinga (Anhinga anhinga), Cattle Egret (Bubulcus ibis), and Wood Stork (Mycteria americana), were most often detected during the aerial survey. Most of these species are large birds that tend to nest higher in the canopy or are white-plumaged, and therefore would be expected to be more visible from the air. Five other species, Tricolored Heron (Egretta tricolor), Reddish Egret (E. rufescens), Black-crowned Night Heron (Nycticorax nycticorax), Yellow-crowned Night Heron (Nyctanassa violaceus), and Glossy Ibis (Plegadis falcinellus), were not detected during the aerial survey, presumably because these dark-plumaged species typically nest beneath the tree canopy. Disagreement between aerial and ground survey results also was caused by the inability of the aerial survey to detect some species when they were present in larger colonies or distinguish resting birds from breeding birds. The aerial detection rate of 45 previously unknown colonies was about 71%. Recommendations for improving future aerial surveys of colonial waterbirds include more use of ground surveys for smaller species of day herons and night herons to augment aerial information and smaller width of flight corridors.

The coastal grasslands of eastern Buenos Aires Province (Argentina) are used by Rufous-chested Dotterel (Charadrius modestus), Tawny-throated Dotterel (Oreopholus ruficollis), American Golden Plover (Pluvialis dominica) and Buff-breasted Sandpiper (Tryngites subruficollis). These species differ in size but all use visual pecking when feeding. The diet of each species was studied, measuring temporal variation in the abundance of invertebrates and dietary preferences of invertebrates. From March 1996 to January 1999, feces were collected of shorebirds on Medaland Ranch grasslands (Villa Gesell District, Buenos Aires Province, Argentina). Pitfall traps were used to capture surface-active invertebrates (from June 1996 until March 1998). All four bird species ate animal and plant items. In all cases, plant fragments rather than seeds dominated the plant fraction. Beetles comprised the dominant item in all four species of shorebirds. Earthworms were important for Patagonian shorebirds, but they were less frequent in the diets of Nearctic shorebirds. Relative use (proportion in the diet) of items differed by site and date. Numbers of captures were high in spring-summer and low in autumn-winter. All shorebird species preferred adult beetles. Rufous-chested Dotterel and Nearctic shorebirds also showed a preference for beetle larvae. In contrast, spiders and ants were avoided by all shorebird species. Diet information from Nearctic shorebirds at other sites in the Northern Hemisphere and in South America, confirmed that co-occurring species within a given region typically had similar diets, but that the same species in different regions showed low similarity. Dietary flexibility allows exploitation of variable resources and, as a consequence, is highly advantageous to shorebirds that migrate over long distances and use a variety of habitats.

Nest-site selection and nesting habitat use by the Sooty Gull (Larus hemprichii) was studied on Jarnein Island in the United Arab Emirates during the 2002 breeding season. Sooty Gull nests were located mainly on the north and northeast sides of the island. Birds showed definite preference for rocky substrates.

The efficacy of long-term predator removal in urbanized areas is poorly understood. The impact of predation on ground-nesting waterbirds, as well as predator abundance and composition in predator removal versus non-removal or reference sites were examined at South San Francisco Bay. The success of natural nests and predator activity was monitored using track plates, trip cameras, wire haircatchers and simulated nests. Removal sites had higher nest densities, but lower hatching success than reference sites. Predator composition and abundance were not different at the removal and reference sites for any predator other than feral Cat (Felis domesticus). Striped Skunk (Mephitis mephitis) comprised the majority (84%) of predators removed, yet remained the most abundant predators in removal and reference sites. Urban environments provide supplemental food that may influence skunks and other nest predators to immigrate into vacancies created by predator removal. Based on the findings from this study, predator removal should be applied intensively over a larger geographic area in order to be a viable management strategy for some mammalian species in urbanized areas.

A case of intra-specific infanticide is recorded in the Great Egret (Ardea alba) and two cases of inter-nest infanticide are reported for the Black-crowned Night Heron (Nycticorax nycticorax).