The Kittlitz's Murrelet (Brachyramphus brevirostris) is a poorly-known species of alcid and a seabird of conservation concern. Nesting murrelets were discovered at Agattu Island in the western Aleutian Islands, and a field study provided new information on nest site selection, chick growth rates and reproductive success. Twelve ground nests were located in upland habitats (441 masl) at inland areas of Agattu (2.3 km from shore). All nests contained one egg or chick. Murrelets tended to nest in association with a ground cover of orange crustose lichens, bare ground, small rocks and graminoids. Estimates of growth rates for the body mass of nestling Kittlitz's Murrelets were lower (K_L < 0.10) than published estimates for other small-bodied alcids with semiprecocial young (K_L = 0.14 to 0.23). Murrelet young departed from nests after 30 days of growth at 47% of adult mass but at 80% of adult wing length. Optimal wing-loading may ensure successful dispersal flights from terrestrial nest sites to ocean habitats. Survival of eggs and young were low during the incubation (0.26; 30 d) and brood-rearing periods (0.22; 30 d), leading to a low probability of nest survival (0.06). Losses during incubation were mainly due to avian predators, whereas mortality of young after hatching was caused by inclement weather. Kittlitz's Murrelets have a suite of life-history traits associated with low reproductive potential (small clutch size, slow growth and poor reproductive success) and may have limited ability to recover from population declines.

Field-collected and hunter-donated ducks obtained during September-January of 1997–98 and 1998–99 were used to determine if food habits and body mass of Northern Pintails (Anas acuta) and Mallards (A. platyrhynchos) wintering in Suisun Marsh (Suisun), California, a managed estuarine brackish marsh, differed from values in the adjacent Sacramento-San Joaquin River Delta (the Delta), a freshwater region of grain fields flooded after harvest. Ducks in Suisun fed primarily on seeds of Sea Purslane (Sesuvium verrucosum), followed by Alkali Bulrush (Schoenoplectus maritimus) and Wild Millet (Echinochloa crusgalli), together forming 73–90% (aggregate % dry mass) of the diets. Ducks in the Delta fed primarily on seeds of Smartweed (Polygonum spp.), followed by corn (Zea mays) and tomato seeds (Lycopersicon esculentum), together forming 62–88% of the diets. Pintails and Mallards collected in Suisun each had similar (5 of 11 seasonal comparisons) or greater (6 of the 11 comparisons) body mass compared to their conspecifics collected from the Delta (90% confidence interval analyses), despite a composite diet in the Delta having about 39% greater metabolizable energy content (ME) and 24% greater protein content than in Suisun. Therefore, diet quality alone was not a predictor of body mass in these two areas. Other factors must have been involved, such as greater food abundance and density, lower waterfowl abundance and density, or lower daily energy costs in Suisun. Direct measurement of these factors should explain the apparent inconsistencies in body mass relative to food quality in these brackish and freshwater habitats.

Interactions of Double-crested Cormorants (Phalacrocorax auritus) and fish in a constricted shallow basin near a cormorant nesting site (Young Island) in Lake Champlain, Vermont were studied. Much of the basin was dominated by submerged aquatic vegetation (SAV), which led to the investigation of how fish residing among SAV could affect cormorant foraging. Data were collected on foraging flocks, individual birds and their stomach contents, the fish community, and SAV from May to September. Fish were most abundant in August and September; they did not migrate from the basin during the warmest time periods or the greatest densities of SAV. Although many fish species (N=28) were collected, Yellow Perch (Perca flavescens) numbers comprised almost half of the fish community and were the major prey, based on numbers, in cormorant stomachs. Double-crested Cormorants regularly foraged in the basin until early August when they began foraging in more distant areas. The shift occurred soon after the peak in SAV biomass and height, which covered essentially the entire area previously frequented by foraging birds. The results indicate that cormorants expand their foraging range when prey become less available. Thus, dense SAV can indirectly contribute to the expansion of Double-crested Comorants, adding complexity to strategies for managing cormorant numbers throughout the lake.

Seasonal variation in abundance, time activity budgets and foraging behavior of non-breeding Marbled Godwits (Limosa fedoa) and Willets (Tringa semipalmata) were compared at four sites at the Laguna Ojo de Liebre—Guerrero Negro saltworks complex, Baja California, Mexico. Habitat use varied between species, seasons and sites. Marbled Godwits (182 ± 44.1 individuals per site) were more abundant than Willets (70 ± 16.1 individuals per site), reflecting their overall pattern in northwestern Mexico. Overall abundance diminished throughout the season (270 ± 69 individuals per site in Oct–Nov, 85 ± 21 in Dec–Jan and 60.2 ± 24 in Feb–Mar), although it remained high at mudflat. Consistent with bill length, Willets foraged mostly by pecking, while Marbled Godwits did so mostly by probing (proportion of pecks: 0.95 ± 0.17 and 0.4 ± 0.27, respectively). Marbled Godwits changed their time activity budgets through the wintering season: time devoted to vigilance changed from 8–23% in Oct–Nov, to 0.4–8% in Feb–Mar whereas time devoted to feeding changed from 12–40% in Oct–Nov to 59–74% in Feb–Mar. This pattern seems to reflect a change in priorities; surviving early in the season and accumulating energy to migrate, later. In both species, differences in use of habitat appeared to be related to site characteristics such as substrate hardness and risk of predation. The mudflat was the site most used and the saltmarsh, the least used. Some individuals in both species used the more risky saltmarsh, but increased the time devoted to vigilance. Thus, habitat quality for non-breeding shorebirds depended on both benefits and costs for foraging birds, and habitat choice by specific individuals was complex and probably involved condition- or state-dependent tradeoffs that balanced metabolic requirements, safety priorities, and, perhaps, social status or dominance.

The Boat-billed Heron's (Cochlearius cochlearius) atypical bill has inspired a half-century of literature addressing its possible ecological and evolutionary implications. Based on a review of this literature and results of a field study conducted in San Blas, Mexico, it can be concluded that the Boat-billed Heron is nocturnal, visuallyfeeding, with a limited and simple feeding repertoire and diet. The heron forages by standing on branches and roots and by walking slowly in shallow water capturing fish and shrimp by lunging and by scooping the surface of the water with its bill. Except for scooping, the feeding repertoire is unexceptional and moreover is typical of other herons that feed by perching on low-hanging branches. Similarly, its food is similar to other nocturnal herons feeding in the same place. Herons obtained about 60 prey items per day. Thus the outlandish bill appears not to be detrimental to the bird's foraging successfully in a manner typical of herons using similar habitat. The bill has been shown to be used in social signaling, which may be its primary contemporary function. Based on available information the exceptional bill of the Boat-billed Heron appears to have few, if any, systematic or ecological implications.

The Lava Heron (Butorides striata sundevalli) is a distinctively dark-plumaged heron that feeds along the rocky intertidal shoreline of the Galapagos Islands. The open shoreline used by the Lava Heron differs markedly from the dense swamps used by most populations of Butorides. Larva Herons feed by standing and by walking slowly at the water's edge, averaging only three steps per minute and catching primarily fish, crabs and prawns. Lava Heron foraging is characterized not only by its use of open shoreline, but by an extreme dependence on standing feeding behavior, frequent shifting of feeding sites following the tidal flux across a broad intertidal zone, and importance of crabs in the diet; but overall its foraging does not differ significantly from that used by Butorides elsewhere. The fundamental Butorides foraging strategy appears to have accommodated the habitat shift from dense bushes to open shoreline. Individuals maintain separate feeding territories, with the nest being placed within the territory of one of the pair. Feeding success was 0.12 prey per minute. In that nesting production is low contrasted with other populations, it appears that food may overall be limiting. The Galapagos population differs from South American Striated Herons (Butorides striata striata) in having a longer and stouter bill, a feature that correlates with the importance of crabs in the diet. Although known for its distinctive dark color, plumage ranges from all black to light grey, similar to South American birds. The dark color has been assumed to provide camouflage against the similarly colored shoreline, but its specific function has not been explained. Dark ventral plumage likely provides camouflage from active fish and crab prey. Dark dorsal plumage likely provides camouflage on the dark shoreline from above. Although the Galapagos lacks predators, four bird species steal prey from herons, suggesting that the dark plumage of Lava Herons may function to provide camouflage against piratical birds. Whereas the complex plumage patterns of most Butorides populations renders those birds cryptic within their usual densely vegetated habitat, dark plumage is similarly cryptic along the exposed dark shoreline of the Galapagos.

Black Oystercatchers (Haematopus bachmani) have been identified as a species of concern by government agencies and conservation organizations because they have small populations and are sensitive to disturbance caused by shoreline and near-shore human activity. Expanding human recreation in Prince William Sound (PWS) may have potential negative consequences on Black Oystercatcher reproduction and on the population as a whole. Almost 2000 km of shoreline in western PWS was inventoried to assess density, distribution and habitat use of breeding Black Oystercatchers each June and July from 2001 to 2004. These efforts identified 94 territories (density 0.030.38 pairs/km). Black Oystercatcher territories were preferentially located on wave-cut platforms and rocky islets as well as gravel beaches but they avoided salt marsh, tide flats and sheltered rocky shores. Within western PWS 186 shoreline campsites were documented and people preferred to camp on gravel beaches. The association between campsites and territories was evaluated, and although there was a positive correlation at the landscape level, direct overlap only occurred on four sites and territories were separated from campsites, on average, by 1.8 km. Impacts associated with direct overlap (e.g., trampling of nests or direct displacement of pairs) may be rare for this remote area.

Little is known about the ecology and population structure of the Reddish Egret (Egretta rufescens). Furthermore, the effects of the near extirpation on genetic variation of Reddish Egrets are unknown. A 223-basepair region of the mitochondrial DNA (mtDNA) control region was sequenced in 149 Reddish Egret samples from sixteen breeding colonies along the Texas Coast to investigate genetic diversity and population structure. Despite experiencing a severe reduction in population size, Reddish Egrets retained a moderate amount of haplotype (0.705) and nucleotide diversity (0.005). A mismatch distribution among haplotypes and non-equilibrium relationship between the number and similarity of haplotypes (Fu's Fs) are consistent with historical population size changes. No evidence of genetic structuring was found among either colonies or color morphs. Reddish Egrets along the Texas Coast appear to form a single panmictic population. The results of this first conservation genetic study of Reddish Egrets serve as a foundation for management and additional research.

Dimorphism in various morphological traits is widely used to sex birds. However, when a threshold is set and there is overlap in the distribution of traits between sexes, there will be an error rate. Macaroni Penguins show limited sexual dimorphism in size, with the distributions of most phenotypic traits overlapping between sexes, making using morphological characters for sexing difficult, although bill depth is used in one discrimination test. Two existing DNA-based PCR tests that use different primer pairs (P2/P8 and 2550/2781 ) were adapted for use with fluorescently labelled primers to enable the size of fragments to be accurately measured via genotyping protocols and sex to be determined. The two molecular tests were applied to the same samples to estimate the error rate within and between tests. Whilst both primer pairs reproducibly identified the sex of the penguins under study with no inconsistencies between tests, the P2/P8 primer pair had a higher success rate of amplification. To estimate the error rates of morphometric tests, they were compared with molecular tests, revealing areas of disagreement. Structure in the error indicated a bias near the morphometric discrimination threshold. We suggest that larger sample sizes in discriminant function analyses and calibration with molecular data can be used to estimate the likelihood of misidentification for any particular value of the trait. A description of where error lies can then be used to target the more expensive and time-consuming DNA tests to check individuals that are most likely to be mis-assigned.

A total of 124 pellets (regurgitated casts) produced by the Neotropic Cormorant (Phalacrocorax olivaceus) were collected monthly between January 2004 and November 2005 from a roosting site at Rosario Lake Chubut, Patagonia, Argentina. Analyses of the samples showed that fish were the most frequent and important prey by number, followed by crustaceans and molluscs. The three fish species inhabiting Rosario Lake were represented in the diet which suggests that this bird is a generalist feeder. However, cormorants positively selected for Patagonian Silverside and Rainbow Trout, which might be related to their foraging strategy and/or to the conspicuousness of potential prey. The estimated annual fish intake by cormorants at Rosario Lake ranged between 2.3–3.7 tons of fish or 16,000–26,000 individuals. The impact produced by the Neotropic Cormorant on recreational fish resources and local fish farms appears negligible.

A wild Little Egret (Egretta garzetta) was observed to take bread, drop it in a pond, wait for the fish to be attracted to the bread, strike at the fish, and successfully catch fish in this way (active bait-fishing). A Grey Heron (Ardea cinerea) was observed, at the same site, to catch fish attracted to bread which had been thrown onto the water by humans (passive bait-fishing). Little Egrets and Grey Herons have not previously been recorded using bait for fishing.

The Phoenix Petrel (Pterodroma alba) is classified as Endangered and its population is declining on most of its breeding islands. However, the exact population size is not clearly known and data are sometimes old and inaccurate, such as for the Marquesas Archipelago, French Polynesia. Hatuta'a Island, Marquesas, was visited for three days in March 2007 to determine whether P. alba was still breeding on this island. The population size was estimated to be more than 200 pairs, compared with the one individual seen 20 years ago. Thus, Hatuta'a's importance for bird conservation in the region has increased.

The Black Guillemot (Cepphus grylle) is a monomorphic, socially monogamous member of the Alcidae. Although aspects of their breeding and foraging ecology have been extensively studied, less is known about possible sex-based differences in morphology, nor whether Black Guillemots mate assortatively based on body size. Using molecular techniques, we identified the sex of 26 male and 21 female Black Guillemots captured in the Canadian Arctic, and measured six external body measurements: outer tarsus length, wing length, culmen length, bill depth, head plus bill length and body mass to test for sexual size dimorphism (SSD) and assortative mating. Overall, males were 1.7% and 8% larger than females in outer tarsus length and bill depth, respectively. Within breeding pairs, bill depth was the most dimorphic trait. Despite these morphological differences no evidence of assortative mating based upon body size was found. Thus, mate choice for body size does not appear to be an underlying mechanism of SSD in bill depth in Black Guillemots.

Nest site choice and construction by ground-nesting shorebirds can have important repercussions for survival and reproductive success, potentially impacting predation risk, mate retention and hatching success. One such decision, lining nests with shell fragments, was investigated in the Piping Plover (Charadrius melodus). Data were collected describing the placement, construction and fate of 34 nests on Cape Cod, Massachusetts, USA in 2003. Model selection criteria were used to determine the habitat variables that most strongly influence nest lining. The best model included variables related to both the immediate surrounding (proportion of the substrate made up of shell and rock, and sand granularity), as well as nest location (distance from the dune). Plovers used more shell fragments in nests that are on shelly, rocky, or coarse-sanded beaches, and when nesting closer to dunes. There was a negative correlation between fledging success and the amount of shell surrounding the nest. These results and related conservation implications are explored for this threatened shorebird.

The first late Oligocene fossil record of a loon (Gaviiformes) is described from the lacustrine deposits of the German locality Enspel. The specimen is an isolated foot, which is associated with a crocodilian tooth. The fossil belongs to a species about half the size of the smallest extant loon, and is morphologically most similar to the Paleogene taxon Colymboides. In all probability it constitutes the prey remains of a crocodilian, which is of particular significance because the distribution ranges of loons and crocodilians hardly overlap today. The Enspel palaeoclimate was warm-temperate and subtropical, and the Enspel specimen and other Paleogene fossils of gaviiform birds raise the, as yet, unanswered question of why loons largely disappeared from inland habitats of the warmer regions.

Incorporating lightweight synthetic lines, nylon fish netting and sailboat and fishing hardware, the drop net is an effective, portable method to trap many different species of shorebirds. During 2006 and 2007 drop nets were used to safely capture more than 265 targeted shorebirds in habitats in North and South America. Shorebirds captured included Calidris sandpipers, Charadrius sandpipers, Buff-breasted Sandpiper (Tringites subruficollis), and dowitchers (Limnodromus).