Nine years (1989/90-2002) of data on a asynchronous pelagic seabird, the White-tailed Tropicbird (Phaethon lepturus), breeding on Aride Island, Seychelles, were used to examine: (1) annual variation in productivity and, (2) the importance of large scale (El Niño Southern Oscillation) factors in explaining productivity levels. In 2001 and 2002, we examined the influence of local scale factors (parasitism by hard ticks Amblyomma loculosum and intra- and inter-specific competition for nest-sites) on productivity. Productivity between years only ranged from 0.21 to 0.37 chicks/breeding pair, but it was nevertheless significantly and inversely correlated with the El Niño index. No influence on productivity was caused by local factors. The frequency distribution of chick deaths varied significantly with chick age in 2001 but not in 2002. Most of the chick deaths were from starvation, in particular for chicks older than 20 days. As opposed to synchronous seabird species, there were no years with total breeding failure in the White-tailed Tropicbird. This may be partly explained by their dispersed feeding in the open ocean.

Visits were made to the Xisha Archipelago, northern South China Sea, from 13 March to 9 April 2003 and 2 April to 7 September 2004, to determine the status of the Red-footed Booby (Sula sula). The Red-footed Booby was found to breed only on Dong Island, (area of 1.55 km²). Random sampling indicated that the island supported approximately 35,500 breeding pairs. The colony is the largest in the west Pacific and comprises more than 10% of the estimated world population. It is suggested that the island may hold more than 100,000 individuals, including fledged birds of the year, and immature and non-breeding birds. The Red-footed Booby nests only in Pisonia grandis trees on the island, and the most serious threat to the breeding colony is from a herd of introduced cows which are consuming the new P. grandis growth that otherwise would develop into potential nesting habitat. Recommendations are made for improved protection of birds on the Archipelago.

The Black-faced Spoonbill (Platalea minor), breeding on Xing-Ren Tuo, arrived from late March to April and left from mid-July to August. The summer group included breeding pairs, non-breeding adults and sub-adults, while some transient individuals were observed irregularly. After arrival, the birds slept and rested on bare rock on the seashore or cliff top. They departed before dusk to feed, returning in the early morning. Pairs formed 15 days before the first egg was laid. The copulation frequency averaged 0.38±0.18 times per hour after pairs formed, and the highest frequency occurred in the early morning. The clutch size was two or three eggs, and the incubation period lasted 26.2±1.5 days (range 25-29, N = 6). Juveniles left their nest after 30 days and could fly freely after 36 days. From 1999 to 2003, the hatching rate of 29 eggs was 86% and the survival rate to fledging of nestlings amounted to 84% of 25 hatched chicks.

Butt-end and lock-on aluminum band loss and wear were studied in the White Stork (Ciconia ciconia) banded in Spain. The risk of loss of butt-end bands increased from 0% to 85% in bands of 0 to 12 years. However, no loss occurred when storks were banded on the tibia rather than in the tarsus. Lock-on metal bands showed a low band loss rate throughout. The results indicated that band loss was mainly caused by the band opening, probably because of frequent contact with mud and water on the tarsus. Aluminum bands should be completely discarded to avoid important biases in analyses of population dynamics, dispersal and survival of storks and other groups. This is currently already done in many banding schemes, but should be applied more generally worldwide.

The impact of Glaucous Gull (Larus hyperboreus) predation on the Little Auk (Alle alle) during breeding season at the Ariekammen slopes in Hornsund was compared between 1983 and 2003-04. During the nestling period, gulls killed more young Little Auks in 1983 than in 2003. During the period of the colony departure in 2003, there were more Glaucous Gulls present and they killed more Little Auks than 20 years previous. Changes were found in the strategy of the colony departure by the Little Auk. In 2004, the rate of fledglings departed from the colony during “day” hours was higher than in 1983 and a higher proportion of fledglings left the colony escorted by more than one adult bird. This could be a consequence of general increase in the Glaucous Gull numbers or a year-to-year fluctuation and needs further investigations.

The Black Tern (Chlidonias niger) is known for insectivory in their breeding range, but they are piscivorous in winter and feed some fish to chicks. Fish have potentially high value for chick provisioning because of their larger mass, but the relative value of fish and insect diets for chick growth is unknown. In 1999-2000, we documented use of fish and insects for provisioning chicks at four Black Tern colonies in Maine and examined chick growth rates at two colonies (Douglas Pond and Carlton Pond) that differed in fish and insect use. Deliveries of fish and insects to broods were documented using video cameras and observations from blinds, while concurrently measuring chick growth in nest enclosures. Fish use was substantial (>25% of deliveries) at three of four colonies. Fish comprised 29% of items and 56% of metabolizable energy delivered to chicks at Douglas Pond compared to 13% of items and 22% of metabolizeable energy at Carlton Pond. Food delivery rate was inversely related to the proportion of large fish in brood diets at Douglas and Carlton Ponds and increased with brood age at Carlton Pond only, apparently due to high insect use. Chick growth rate did not vary with respect to fish and insect composition of diets. It is concluded that adults were able to raise chicks through age 12 d at comparable growth rates with insect- or fish-dominated diets. Use of fish may be more energy efficient for adults, and the capability to use both fish and insects may reduce potential variability in food availability during the breeding season.

Nest predators commonly limit productivity of Least Tern (Sterna antillarum) breeding colonies in both natural and artificial habitats. In 2003 and 2004 we used remote still cameras aimed at model nests and remote video cameras aimed at occupied Least Tern nests to identify predators of Least Terns breeding at Gibson Lake, an artificial breeding area in southwestern Indiana, USA. At the primary breeding site, a narrow gravel dike that bisects Gibson Lake (center dike), Ring-billed Gulls (Larus delawarensis) were responsible for 100% and 75% of known predation events on model nests in 2003 and 2004, respectively. Throughout the 2004 breeding season, the proportion of model nests disturbed by Ring-billed Gulls on the center dike was strongly correlated with their numbers roosting on the center dike. We recorded predation by Ring-billed Gulls on six Least Tern chicks and two eggs in 2004 with remote video cameras. Our evaluation of the predator community at Gibson Lake strongly implicated Ring-billed Gulls as a major source of mortality for breeding Least Terns.

The aim of this study was to analyze the variability observed in the food and feeding biology of the Common Tern (Sterna hirundo) in relation with environmental factors operating in nonbreeding season in Argentina at different spatial and temporal scales. Fish constituted more than 60% of the diet of the Common Tern in terms of biomass in all years, while insects never exceed 40%. A total of 25 fish species and nine insect species (Orders Coleoptera, Lepidoptera, Odonata and Hemiptera) were found in the diet. In four of six years, terns preyed more on marine fish (68%) while in 2001-02 terns foraged mostly on freshwater species (60%). Estuarine fish species were eaten in all years (>10%). Freshwater prey were found only in seasons with high local rainfall. Local wind-speed had a significant effect on the daily proportion of insects and fish prey found in the diet, with more insects (hence less fish) consumed on days with high winds. La Plata River overflow seasons were correlated with negatives values of the Southern Oscillation Index (SOI). We found less estuarine fish (e.g., Whitemouth Croacker, Pejerrey Silverside) after a month with a low SOI value. A positive trend was also observed between La Plata river outflow and more marine fish in the Common Tern diet. The observed environmental variability in winter quarters and the fluctuation in the use of different food sources may affect the individual quality of terns and not only the survival of individuals during the nonbreeding season but also the timing of migration or breeding performance of adults during the following reproductive season.

The Common Tern (Sterna hirundo) rarely produces more than one brood per breeding cycle. In 1996, 18 of 365 pairs (5%) of Common Terns nesting at a Lake Ontario colony laid second clutches while caring for first-brood nestlings; no second clutches were recorded during four previous breeding seasons at this location. Second clutches were smaller than first clutches of the same pairs (2 versus 3 eggs), and were initiated when first broods contained 1-3 nestlings that ranged in age from 12-22 d. Success of second clutches was low. Only two nestlings, from one second clutch, survived for >18 d; all remaining second clutches were abandoned or predated prior to (N = 16) or just after (N = 1) hatching. Three proximate factors were examined, within and among years, related to the production of second clutches: 1) earlier initiation of first broods, 2) reduced parental effort toward first broods, and 3) foraging conditions during rearing of first broods. Second clutches were not related to earlier breeding or reduced parental effort: clutch initiation dates, clutch sizes, and egg volumes of first clutches were similar among years, and first-clutch size and initiation date did not differ between pairs producing one versus two clutches. Conversely, parental care patterns in 1996 had several unusual characteristics compared to other years, including: (1) shorter provisioning trips, (2) higher provisioning rates, and (3) reduced rates of kleptoparasitism. These characteristics suggest that an abundant food supply close to the colony in 1996 was the likely proximate explanation for second-clutching.

Fourteen Common Terns (Sterna hirundo) were radio-tagged on their wintering grounds at Lagoa do Peixe, Rio Grande do Sul state, southern Brazil. Aerial radio-tracking was made along 850 km from northern Rio Grande do Sul state to Montevideo, Uruguay. During 23.6 h of tracking in February 2003, we recorded 100 locations of 12 radio-tagged terns. Birds were located within a range of 165 km from the tagging area, and most locations were at sea (74 at sea vs. 26 roosting on the beach), due to frequent movement of the birds when feeding and most tracking during feeding periods. Each bird was located 4-14 times (mean = 8.3 locations/bird). Common Terns fed predominantly between 15-20 m isobaths (56% of at sea locations), and 10-15 m isobaths (32%), which corresponded to a maximum of 8 km offshore. Minimum distance traveled in five days of intensive tracking was 46 km, and maximum distance was 167 km. Daily movement was 19 km on average (minimum 6 km d^-1, maximum 49 km d^-1). Nine out of 12 birds were found at sea in both early morning and late afternoon periods. Eight out of 12 birds were recorded feeding at sea in consecutive periods of the day (morning and afternoon), indicating two feeding trips a day.

Despite current anthropogenic alterations to riparian areas and littoral zones of lakes, little information is available on how human-induced alterations affect lacustrine habitat use by many piscivorous birds in northern Wisconsin, USA. The influence of lake characteristics and human disturbance on species richness and the presence of seven species of piscivorous birds was determined on 98 lakes located primarily in Vilas and Oneida counties, Wisconsin. Lakes were surveyed for species presence using shoreline perimeter surveys with total searching time standardized to two, one-hour surveys per lake. Piscivorous bird species richness was highest on large lakes with high pH levels. Using logistic regression, many species were found to be present on lakes possessing characteristics associated with high abundances of fish, including lake surface area, pH, and water clarity. At least one of these variables was included in the final models for species richness and presence of the Common Merganser (Mergus merganser), Bald Eagle (Haliaeetus leucocephalus), Great Blue Heron (Ardea herodias), and Ring-billed Gull (Larus delawarensis). Three species avoided lakes possessing characteristics associated with high levels of human disturbance; the Osprey (Pandion haliaetus) was not found on lakes with low percentages of macrophytes, the Common Merganser was absent on lakes with low water clarity, and the Common Loon (Gavia immer) was not present on lakes with many cottages. Many species of piscivorous birds were widespread regardless of the degree of human development, indicating that habituation to humans may have occurred. In addition, density-dependent factors may have precluded identification of optimal lake characteristics for some species due to habitat saturation.

Large colonies of nesting ciconiiform birds have recently become an important tourist attraction in the Brazilian Pantanal. Visits to these colonies are uncontrolled and there is growing concern about disturbance to the breeding birds. In 1998, an experiment was conducted using different treatments within a single, large, heavily visited colony to assess the effects of different kinds of tourist viewing on the breeding behavior and nesting success of the Wood Stork (Mycteria americana). Pedestrian viewing, when more than 75 m from the nearest active nest, produced no detectable change in breeding success or behavior. However, boats passing within 20 m of nests were associated with significant changes in the time budgets of incubating adult storks. Most breeding failure occurred prior to hatching and was significantly higher in the boat-treatments in comparison with controls. It is suggested that the elevated level of nest failure observed in the boat-treatment group is evidence of biologically significant disturbance. These conclusions are supported by observations taken in 2000 when boats were excluded from the colony. Behavioral responses at the time of disturbance are typically used as indicators of effects when determining safe approach distances for birds. However, in this study, behavior during disturbances was unrelated to the eventual effect of disturbance. These findings have been incorporated into suggestions for the measurement of disturbance and management of tourist visits to bird colonies.

We studied the foraging behavior of the Double-crested Cormorant (Phalacrocorax auritus) on Oneida Lake, New York, by monitoring the activities of 27 radio-tagged birds in July and August of 1999 and 2000. A total of 224 locations were obtained of cormorants actively diving, and presumed foraging, at the time of detection. A geographic information system was used to examine foraging distances from the nesting island, the water depth and type of substrate at preferred foraging sites, and to estimate kernel home ranges for analysis of individual foraging site fidelity. An explanatory model was developed to determine parameters affecting the distance to cormorant foraging sites. The mean distance to foraging locations of tagged cormorants from the colony site was 2,920 m (SE ± 180 m, max = 14,190 m), and 52% of the locations were within 2,000 m of the nesting island. No cormorant was observed making daily foraging trips to outside water bodies. Mean foraging distance was greater during morning than in the afternoon, and there was a significant effect of the time of day on distance. There was no significant effect of sex date, a seasonal measure on distance to foraging location. Individual cormorants exhibited fidelity to specific foraging sites. Most cormorants foraged in close proximity to the nesting island much of the time, while those detected further from the island tended to return repeatedly to the same locations. Ninety percent of the foraging locations were in water depths ≤7.5 m, and most were in water 2.5-5 m deep. Compositional analysis of habitat use revealed a preference for these depths, along with substrates of cobble with rubble, and silt with clay.

The diet of the Great Cormorant (Phalacrororax carbo) was studied on the Finnish side of Gulf of Finland, Baltic Sea, by collecting regurgitated fish in a colony. Most abundant species of fish were Viviparous Blenny (Zoarces viviparus), Roach (Rutilus rutilus) and Perch (Perca fluviatilis), most of which are economically unimportant. Cormorants switched their diet during the breeding season. Before young were hatched, cormorants ate mainly Roach and Perch; when young were less than 25 days, old they ate mainly small Viviparous Blennies. Later, adults provided larger Roach and Perch for their young. The results suggest that several fish-sampling visits are needed to record the food captured by cormorants during the breeding season. Few samples restricted in time may bias the composition of fish species and size of the fish in diet.

One possible explanation for the evolution of white plumage in herons is an adaptive advantage for foraging. Under this hypothesis, white plumage is cryptic to aquatic prey; thus white-plumaged birds may be more prone to forage in deep water habitats, where they would be cryptic, using passive foraging tactics. Dark-plumaged birds foraging in shallow water habitats, where they are presumably more visible, use active tactics. These hypotheses were tested by investigating choice of water depth and choice of foraging tactics by conducting paired foraging observations between color morphs within the plumage dimorphic Reddish Egret (Egretta rufescens). Water was divided into four depths classes: deep (>15 cm), intermediate (5-15 cm), shallow (1-5 cm), and mudflat (<1 cm). There was no difference in time spent in different water depth classes between the two color morphs of the Reddish Egret. However, there was a significant interaction between color morph and depth of water for time spent actively foraging. The white morph of the Reddish Egret was more active in intermediate depths of water than the dark morph while the dark morph was more active in shallow depths of water. These results support the hypothesis that Reddish Egrets may alter foraging tactics based on their degree of crypsis to prey.

We report the northernmost breeding record of the Reddish Egret (Egretta rufescens) along the North American Atlantic Coast. Nesting activity was first seen in late May 2004, and on 6 July 2004 a nest was discovered with two young chicks on Marsh Island, a barrier island located within Cape Romain National Wildlife Refuge, South Carolina, USA. Reddish Egret nestlings were last observed within 1 m of the nest on 30 July 2004. This represents a northward extension of ca. 450 km in the breeding range of this species and, for the U.S. Atlantic Coast, the only recorded instance of nesting north of Florida.

The Chinese Egret (Egretta eulophotes) is a globally threatened species with little quantitative data on its breeding biology. Observations conducted in 2003 at Xing-Ren Tuo in Liaoning Province indicated that the species had a low within-pair copulation frequency and a relatively high extra-pair copulation frequency. The occurrence of extra-pair copulations depended upon the absence of the cuckolder's mate and the cuckolded male. There was an asynchronous fading in bill color between sexes after laying, which probably accounted for the male's preference for an egg-laying female as extra-pair mate. Ground nesting induced a modified tactic: the male approached another nest by walking covertly, which led successful mounting of the female.

The first case of juvenile White Ibis (Eudocimus albus) intraspecific predation is reported from the Florida Everglades.