A population survey for Long-billed Curlews (Numenius americanus) was completed in the western United States and Canada in 2004 and 2005. This survey was conducted during the early breeding season, using a stratified random sample from habitat strata. The survey design was a 32-km road transect with 40 five-min point counts at 800-m intervals. Detection probabilities were estimated using the removal method in which observations in one-min intervals were removed from further consideration. Model selection based on Akaike’s Information Criterion resulted in a model where detection probability varied among observers, but was constant throughout the point count for each observer. Estimated detection probabilities for the point count duration were greater than 0.68 for all observers. Counts were adjusted for detection probability and then used to estimate the mean density within surveyed point count plots. Overall, the range-wide estimate of total population size was 161,181 individuals. The estimates were 183,231 individuals for 2004 and 139,131 for 2005, with corresponding 90% confidence intervals of 113,324 to 422,046 and 97,611 to 198,252, respectively. In addition to estimates for both the United States and Canada, population densities were estimated for geographic sub-regions: Bird Conservation Regions, Shorebird Planning Regions, administrative regions, and for each Canadian province. Issues and assumptions inherent in the study design and their implications are discussed.

We estimated annual survival probabilities of color-banded adult Herring Gulls (Larus argentatus) breeding in a colony on the Canadian shore of Lake Ontario, between 1981 and 1984, and between 1993 and 1998. During the study, major changes occurred in prey fish availability, fish-eating bird abundance, and organochlorine contaminant exposure. We used capture-mark-recapture models and an information-theoretic approach to model selection to explore the importance of indices for these environmental variables and the role of year and sex as exploratory effects. In our models, year but not sex acquired strong support suggesting important annual variation in our apparent survival (survival confounded by permanent emigration) and encounter probabilities. The arithmetic mean of our model-averaged apparent survival probabilities provided an estimate of 0.91 (0.02 SE), and four out of the seven estimates were high for the species (≥0.93). Our model-averaged estimates suggested that apparent survival declined after 1995 to a low of 0.79 ± 0.07 (SE). Of the three environmental covariates fitted to survival, only the abundance of Alewife (Alosa pseudoharengus) acquired strong support as an explanatory variable. Annual fluctuations in survival and the decline after 1995 may be a reflection of nutritional stress resulting from the decreased availability of lipid (energy) and high quality protein from this prey species, following the arrival of the exotic Zebra Mussel (Dreissena polymorpha). These nutritional impacts may be exacerbated by some of the PCB-associated sublethal health effects documented in these gulls over the period of this study. Our limited success at isolating other important environmental covariates reinforces the difficulty posed in identifying the critical components of the complex of environmental variables encapsulated in ‘time’.

The nest survival of the Black Skimmer (Rynchops niger) in coastal Mississippi was modeled to better understand their breeding biology and suggest management strategies for protecting nesting colonies. During the 2004 and 2005 breeding seasons a total of 301 nests was monitored and hatching success was 67% in 2004 and 39% in 2005. Mean clutch size differed between years, although mean incubation length did not differ between years or between colonies on the mainland and barrier islands (P = 0.70). Nest survival was influenced by year, seasonal variation within year, clutch size, and colony. Nest survival was greatest in 2004, and within years nest survival followed a seasonal pattern where it was high from May through late June and then decreased through early August. Large clutches had greater survival than small clutches. There was considerable inter-colony variation in nest survival, and it appeared that low survival was correlated with disturbance risk at many colonies. This study provides the first detailed information on the nest survival of the Black Skimmer in Mississippi, increases the understanding of seasonal variation and other influences on nesting success, and provides a basis for suggesting conservation measures for this species during the nesting season.

Resightings of Razorbills (Alca torda) banded as chicks on the Gannet Islands, Labrador (N = 1,873 resightings of 638 individuals) and Machias Seal Island, New Brunswick (N = 870 resightings of 291 individuals) were used to estimate the timing and age at first return to the natal colony and age at first breeding. In total, 14 one-year-old and 110 two-year-old birds were observed on land. All one- and two-year-old birds were seen for the first time on the islands late in the breeding season after laying had occurred, with two-year-olds returning to the colony on average three weeks earlier than one-year-old birds. Age at first breeding was significantly lower on Machias Seal Island than the Gannet Islands, 3.88 ± 0.13 SE and 4.40 ± 0.13 SE years, respectively (range two to six years, N = 123). Four two-year-old birds were observed engaging in courtship and breeding behaviors, including copulation. Overall, age at first return and breeding was lower than for known European Razorbill colonies and is likely due to low breeding densities and fidelity at the two North American colonies studied.

Between 1989 and 2003 colonies of Little Terns (Sterna albifrons) occurring in the lagoon of Venice (55,000 ha; Italy) have been surveyed. Each year the number of breeding pairs ranged between 31 (in 1997) and 611 (in 1995), with a yearly mean of 205 (SD = ±163). An overall stability in breeding numbers was observed, with an increase from 1989 to 1995 and a decrease afterwards. 34 sites were used; 13 (38%) were saltmarsh islets, twelve (35%) dredge islands, four (12%) beaches and the remaining five (15%) artificial beaches. Colony size median ranged between 25 and 15 pairs, with no differences among site typology. Sites used each year ranged between one and twelve, with a mean of 4.7 ± 3.0 sites. Turn over rate was high, 60%, and it did not vary significantly among colony sites type. Larger colonies were not more stable than smaller ones. Despite historically breeding at both beaches and saltmarshes, over the 15 years of study a shift in colony sites from beaches to saltmarshes and from these to dredge islands has been documented. Dredge islands, taken as a whole, were over the last years the most important breeding site in the entire lagoon.

We conducted multiple Common Goldeneye (Bucephala clangula) aerial surveys between 1 May and 31 July 2004 and 2005 on the Péribonka River, where a new hydroelectric reservoir will be created in 2007. We also conducted single pair and brood surveys on randomly chosen 5 × 5-km plots on the River drainage basin. Objectives were to assess the validity of the impact assessment surveys of 2002, examine the variation in pair and brood numbers, and determine recruitment and habitat characteristics related to productivity. During both years, the number of indicated breeding pairs (IBPs) declined steadily through May, whereas the social index (paired males/lone males) remained stable, declining only when few IBPs were located. However, backdated number of paired and lone males from observed broods suggested that the number of pairs remained maximal and constant during a three-week period centered on the fourth week of May in 2004 and the second week of May in 2005. IBP density (IBPs/10 km of shoreline) was 1.40 on the River and 0.64 in its drainage basin on average in 2005 (no surveys in 2004). When compared to results of the Black Duck Joint Venture (BDJV) surveys, IBP density was higher on the River by 0.69 IBPs in 2002, whereas densities in the two areas differed only by 0.07-0.29 in 2004 and 2005. No difference in brood density was perceived among survey sections and years. Recruitment rate was 0.15 in 2002, but increased to 0.57-0.67 in 2005 and 2004. Variables related to wetland area and distance to wetlands explained most variability in IBP and brood locations. We believe that timing of surveys and weather were the primary factors that affected difference in productivity estimates between 2002 and the 2004-2005 period.

We used logistic regression to model the effects of weather, habitat, and management variables on Greater Sandhill Crane (Grus canadensis tabida) nest success at Malheur National Wildlife Refuge in southeast Oregon. We monitored 506 nests over 9 breeding seasons. Mean apparent nest success was 72% ± 4% and varied from 51 to 87%. Nest success was lower one year after a field was burned and declined with nest initiation date. Nest success was higher during warmer springs, in deeper water, and in years with moderate precipitation. Haying, livestock grazing, and predator control did not influence nest success. We suggest the short-term consequence of burning on nest success is outweighed by its long term importance and that water level management is the most important tool for managing crane nest success. Finally, studies of brood ecology are needed to develop a more complete picture of crane nesting ecology.

Habitat use patterns are influenced not only by characteristics of the habitat itself, but also by the nature of the surrounding landscape. Conservation of waterbirds in agricultural areas, therefore, needs to consider the effects of landscape patterns on the occurrence of species in individual fields. The relationships between the densities of waterbirds using flooded rice fields in winter and characteristics of the surrounding landscape were analyzed in California’s Sacramento Valley. The spatial scale at which the landscape was described was varied by calculating the amount of each habitat type within 2 km, 5 km, and 10 km of each field’s boundary. Waterbird densities in flooded fields were related to landscape patterns in various ways, but the nature of the relationships differed among taxonomic groups and depended on the scale at which the landscape was characterized. Densities of geese, wading birds, and shorebirds were positively correlated with the amount of wildlife refuge or semi-natural wetland in the vicinity of a flooded field. These two variables were highly correlated with each other and their effects could not be assessed independently. The abundance of flooded rice fields in the landscape was less likely to be related to bird use of flooded fields, but was positively related to duck densities at a 5 km scale and negatively related to shorebird densities at a 10 km scale. These results suggest a number of hypotheses about the ways in which landscape scale patterns of farmland management might affect waterbird use of individual fields, with potential repercussions for both birds and farmers.

Increased human use of coastal areas threatens the United States population of American Oystercatchers (Haematopus palliatus), a species of special concern. Biologists often attribute its low numbers and reproductive success to human disturbance, but the mechanism by which human presence reduces reproductive success is not well understood. During the 2003 and 2004 breeding seasons, 32 nesting attempts of American Oystercatchers were studied on Cumberland Island National Seashore (CINS). Behavior was examined with and without human activity in the area to determine how human activity affected behavior. The oystercatchers’ behavioral responses (proportion time) were analyzed with and without human or intraspecific disturbances using mixed models regression analysis. Proportions of time human activities were present (≤300 m from oystercatchers) during observations averaged 0.14 (N = 32, 95% CI = 0.08-0.20). During incubation, pedestrian activity near (≤137 m) oystercatchers reduced the frequency of occurrence of reproductive behavior, but pedestrian activity far (138-300 m) from oystercatchers had no effect. Vehicular and boat activities (≤300 m) had minimal effects on behavior during incubation. During brood rearing, an effect of pedestrian activity near oystercatchers was not evident; however, pedestrian activity far from oystercatchers increased the frequency of reproductive behavior. Vehicular and boat activity had no effects on behavior during brood rearing. Of 32 nesting attempts, two failed (<10%) because of human disturbance and were located in areas of greater human activity (south end). Managers on CINS should minimize pedestrian activity near nests (≤137 m) during incubation. During brood rearing, protection from pedestrian activity should be increased, when possible, to >137 m and vehicular activity should be minimized at current levels or less.

Breeding success of African Black Oystercatchers (Haematopus moquini) was monitored over three austral summers on Robben Island, South Africa from 2001 to 2004. Robben Island is a busy tourist destination which has a resident population that live and work on the island in addition to tourists that visit the island daily. Potential predators of birds’ eggs and chicks include feral cats (Felis catus), Kelp Gulls (Larus dominicanus), Mole Snakes (Pseudaspis cana) and House Rats (Rattus rattus). The mean number of fledglings per pair declined from 0.74 in the first breeding season to 0.41 and 0.35 in the subsequent breeding seasons. This fledgling success slightly exceeded the threshold estimated to maintain a stable population, and is similar to fledging success observed in other oystercatcher species. The lower fledging success in the second and third breeding seasons compared to the first breeding season were increased depredation of eggs and chicks and high-tide events on 17 February 2003 and 10 February 2004. Predation can be aggravated by human disturbance, and it was found that the area with greatest resident and tourist activity had the greatest egg and chick losses in all three breeding seasons. The area adjacent to the disturbed area had reduced breeding success in the second breeding season, possibly a result of increased predation associated with the settlement. Breeding success near the Kelp Gull breeding colony decreased in the third breeding season; the period during which the greatest number of Kelp Gulls were breeding. The potential success of a breeding attempt decreased if incubation of the clutch started later in the breeding season.

The spring condition hypothesis (SCH) states that the current decline of the North American scaup population (Lesser [Aythya affinis] and Greater Scaup [A. marila] combined) is due to a decline in quality or availability of scaup foods on wintering, spring migration, or breeding areas that has caused a reduction in female body condition and subsequent reproductive success. Our previous research indicated that forage quality in diets of Lesser Scaup (hereafter scaup) at two sites in Northwestern Minnesota was lower in springs 2000-2001 than that reported for springs 1986-1988, consistent with the SCH. Accordingly, we further tested the SCH at a landscape scale, by comparing amounts of amphipods in diets (index of forage quality) of scaup (N = 263) collected in springs 2003-2005 from seven eco-physiographic regions in Iowa, Minnesota, and North Dakota in relation to data from Northwestern Minnesota during springs 2000-2001. We found that aggregate percentages of Gammarus lacustris and Hyalella azteca (amphipods) in scaup diets during springs 2000-2001 in Northwest Minnesota were similar to those in the Iowa Prairie Pothole, Minnesota Morainal, Minnesota Glaciated Plains, Red River Valley, and Northwestern Minnesota in springs 2003-2005; however, scaup consumed relatively higher aggregate percentages of Gammarus lacustris and Hyalella azteca in North Dakota Missouri Coteau and North Dakota Glaciated Plains. Females in Iowa were over three times less likely to have consumed food than those in North Dakota, despite previous research indicating similar foraging rates among these regions. Mean mass of scaup diet samples throughout the upper-Midwest were 77 mg (49%) and 87 mg (52%) lower than those of historical studies in Minnesota and Manitoba, respectively. We conclude that there has been a decrease in forage quality for scaup in Iowa and Minnesota and a decrease in the amount of forage consumed throughout the upper-Midwest, consistent with the SCH.

Atlantic Puffin (Fratercula arctica) chick growth, diet, feeding rate and early survival and adult body condition were quantified on Hornøya, North Norway in 2002 and 2003 after a long-term change in diet from large Capelin (Mallotus villosus) and Sand Lance (Ammodytes spp.) in the early 1980s to smaller, poorer quality gadids, Sand Lance and Herring (Clupea harengus). The results were compared with data collected in 1980-1982, when feeding conditions were considered very favourable. Chick growth was similar in both periods. The breeding adults compensated for reduced food quality by increasing the feeding frequency, such that the chicks received the same amount of fish (g d^-1 and kJ d^-1) or even more in 2002-2003. This increase in activity did not, however, result in a decline in adult body mass, suggesting that prey were abundant close to the colony and that the parents did not suffer from the apparent increased feeding effort.

In this study, the relationship between physical attributes of sandy beaches, levels of human disturbance, and shorebird occurrence was investigated. The linear density km^-1 of shorebirds on 42 km of sandy beaches in Monterey Bay, California was documented from late autumn through spring, and the relationship of shorebird densities to two physical variables (slope of beach swash zone, total beach width), one spatial variable (distance to Elkhorn Slough, a wetland of regional importance for shorebirds), and relative level of human disturbance was analyzed using stepwise multiple regression. The six most abundant species were Sanderling (Calidris alba), Willet (Tringa semipalmata), Marbled Godwit (Limosa fedoa), Black-bellied Plover (Pluvialis squatarola), Whimbrel (Numenius phaeopus) and Snowy Plover (Charadrius alexandrinus). Mean abundance of four of the six most abundant species (Marbled Godwit, Willet, Whimbrel, Black-bellied Plover) was negatively related to swash zone slope; flatter beaches supported more shorebirds. Mean abundance of all species analyzed was negatively related to distance to Elkhorn Slough; beaches closer to the mouth of Elkhorn Slough supported more shorebirds. Total beach width had no effect on shorebird occurrence, and level of human use appeared to have no effect. Most shorebird species were more abundant on beaches at low than at high tide, indicating that sandy beaches provide important foraging habitat regionally.

Urban populations of several gull species worldwide are increasing dramatically and this is often assumed to be a result of greater access to anthropogenic food obtained in urbanized environments. This research investigated the potential effects of an anthropogenic diet on the mass and body condition of Silver Gulls (Larus novaehollandiae) by comparing birds at a remote, non-urbanized site (Furneaux Island Group) with those at an urbanized (Hobart) site in Tasmania, Australia. The mass, size and body condition of gulls were independent of whether or not a bird was breeding, and independent of the stage in the breeding cycle. Male gulls from this urban environment were heavier and of greater body condition than the structurally identical, non-urban gulls, but no differences were detected between females.

Although shorebirds are detrimentally affected by marine oil spills, they are often overlooked during rescue and rehabilitation efforts. This note describes a rescue and successful rehabilitation effort of an oiled adult and a juvenile Hooded Plover (Thinornis rubricollis) in Victoria, south-eastern Australia, during an oil-spill which oiled almost 1% of the State’s population of this threatened beach-nesting species. Two birds requiring intervention were located, selectively captured, cleaned and released. Both have survived at least two years after the spill and have bred, with at least one successfully fledging young. The fledgling has also successfully bred. Two nests with eggs present during clean-up operations were protected and hatched successfully. This small case study indicates that at least some groups of breeding shorebirds, such as plovers and dotterels, can be effectively rescued and rehabilitated during oil spills, and hence should not be overlooked during such circumstances.

In herbivorous birds the processing rate of food is constrained by gizzard capacity. To enhance digestive processes, many species ingest grit to grind the food. Grit ingestion, however, may further limit the capacity of the gizzard. Graylag Geese (Anser anser) wintering in SW Spain fed mainly on Alkali Bulrush (Scirpus maritimus) tubers, showing a preference for small tubers. This preference may be due to a faster disintegration of small tubers than larger ones inside the gizzard. As larger tubers are likely coarser than smaller tubers, more grit would be necessary to process larger tubers. However, the ingestion of more grit to grind large tubers would be at the expense of ingesting additional tubers because of gizzard capacity limitations. Under these circumstances, there may be an inverse relationship between tuber size and amount of grit ingested to optimize food ingestion. Indeed, we found such a relationship. Grit facilitated the disintegration of tubers. This suggests that relying on some amount of grit to facilitate the grinding of food should outweigh the loss of gizzard capacity to the amount of food ingested.

We measured Sanderlings (Calidris alba) at Chaplin Lake, Canada during the northward migration and compared data with unpublished information from wintering grounds of Chile and Peru. The morphological analysis show significant differences in weights between and amongst localities. These results can be explained by the period of the migration cycle in which the birds were measured. The birds were significantly heavier at the end of the non-breeding season and during migration.

A total of 2,395 hybrid records were obtained from Central Europe [Austria (N = 45), Belgium (N = 229), Germany (N = 1,628), France (N = 82), Netherlands (N = 9), Switzerland (N = 392), other countries (N = 10)]. Diving duck hybrids were most common (60%) followed by those of geese. Records of hybrids increased significantly between 1934 and 2006. Crosses of indigenous species made up 1,795 of all records and 600 records were crosses with at least one non-native or alien invasive species. Hybrids within the genera Anas, Aythya and between diving and dabbling ducks occurred more often between indigenous species than expected, while geese hybrids occurred more often with non-native species. Aythya hybrids showed a clear seasonal pattern with a peak of numbers during midwinter while most of the Anser hybrids are rather sedentary. Increases in hybrid records may be due to increased use of field guides and number of observers.

Fledgling Double-crested Cormorants (Phalacrocorax auritus) were observed practicing food manipulation techniques with large sticks, algae, and shells at their respective natal colonies in eastern Lake Ontario, North Channel of Lake Huron, and Lake of the Woods. Although practice behaviors have been documented for other species of waterbirds, this behavior has not been recorded previously for Double-crested Cormorants.

On 22 March 2007, I observed Royal Terns (Sterna maxima) flushing and capturing flying fish off the northern tip of the Yucatan Peninsula. Individual terns struck the water which flushed flying fish out of the water and allowed other terns to capture them in midair. This observation is an example of opportunistic foraging by conspecifics.