We report evidence of likely nesting of the Ashy Storm-petrel (Oceanodroma homochroa) on islets adjacent to Vandenberg Air Force Base in northern Santa Barbara County, California, USA. Ten storm-petrels, along with extensive suitable habitat in the area, suggest a small colony of breeding birds. Other offshore islets along California’s central coast might hold small numbers of storm-petrels. In addition, there are possibly breeding storm-petrels in suitable remote mainland areas, such as at Vandenberg Air Force Base.

During the austral summer of 2000/01 a census of breeding King Penguins (Aptenodytes patagonicus), Gentoo Penguins (Pygoscelis papua) and Rockhopper Penguins (Eudyptes chrysocome) was carried out in the Falkland Islands. Results from this census were compared with those from the previous census of 1995/96. The number of King Penguin chicks decreased by 19% from 339 to 275, which is probably a reflection of variable breeding success, rather than a decline in breeding pairs. The number of Gentoo Penguins increased by 79%, from 64,426 breeding pairs in 1995/96 to 115,327 breeding pairs in 2000/01. The Rockhopper Penguin numbers appeared to be stable, with 286,964 breeding pairs in 2000/01 compared to 263,590 breeding pairs in 1995/96 (the difference being within the error margin).

Data on the diving activity of the Little Penguin (Eudyptula minor) as recorded by data loggers are few. We monitored the foraging parameters of free-ranging Little Penguins, breeding at Penguin Island, Western Australia, using a small, hydrodynamically shaped time-depth recorder. Data were obtained for one, two and three consecutive foraging trips of three, one and two birds, respectively. These data showed that individual Little Penguins presented distinct diving depths that are consistent from one trip to the next. Four birds exploited shallow depths, around 1-5 m, but two other birds always chose to dive deeper, to around 8-10 m. No trends could be established between the adult mass or the chick mass and the preferred diving depths. The causes and consequences of these individual diving strategies are discussed.

For most birds, it is difficult to study what life would be like without nest sites. In penguins, however, nesting and non-nesting species can be compared. We contrasted the King Penguin (Aptenodytes patagonicus), which has no nest and carries its chick on its feet, with the Macaroni Penguin (Eudyptes chrysolophus), which has a nest similar to other birds. We investigated the use of the nest site when it ceased to be necessary, that is, after chick emancipation during the crèche period. When adults return to their crowded colony from foraging at sea, both penguin species exhibit individual recognition between parents and chicks via calls. Observations were made on how parents find and feed large chicks. We examined whether the use of the empty nest as a geographical meeting place was advantageous to Macaroni Penguin parents looking for their chicks, and whether the more sophisticated recognition of calls aided King Penguin parents in searching for their chicks. Macaroni Penguin parents found their chicks in about half a minute, giving two or three calls to bring chicks to the site of their previous nest. In contrast, King Penguin parents took longer (about three minutes) to find their chicks, and gave four or five calls to attract chicks. In addition, about a quarter of King Penguin parents had to walk an average of 11-12 m through the crèche in order to find a chick to feed. For Macaroni chicks and their parents, the nest was used as a “rendezvous” location that facilitated reunion.

The problem of waterfowl becoming entangled and killed in netting suspended over fishponds, and the effectiveness of this technique in excluding birds from fishponds, was studied at two fish farms in Israel. A variety of physical and environmental factors of 101 netted fishponds with 20 net types were recorded, as were the number and species of dead birds entangled in the netting, and those observed alive under the netting. Numbers of dead birds were mainly a function of the net’s visibility: with fewer dead birds in small mesh size, and also in thick or dark-colored netting. Large numbers of dead birds occurred in netting made of thin monofilament even though it had small mesh size. The number of live birds at netted ponds was mainly a function of poor net maintenance, rather than net type. The results were used to formulate guidelines for using netting over fishponds in Israel, that include: fishpond netting should be made of thick, dark-colored material with small mesh size (<5 cm), and a total ban should be imposed on the use of thin monofilament nets. These guidelines will allow for better bird conservation, while reducing conflict between fish-farm managers and piscivorous birds.

Sooty Terns (Sterna fuscata) have been extirpated from some islands in the Seychelles through habitat modification, introduction of exotic predators and over-exploitation of their eggs. Recently, removal of exotic predators and habitat restoration have made some islands available for the re-introduction of or re-colonization by former breeding birds. Attempts will be made to encourage Sooty Terns to re-colonize formerly occupied islands that are now deemed suitable to support colonies, using decoy models and broadcasts of recorded vocalizations. As a prelude to these attempts, this study measured the sound levels produced within a Sooty Tern colony at different times of day and season, in order that broadcasts can reasonably well simulate the sounds produced naturally. Statistically significant diurnal and seasonal differences in sound levels were recorded, related to differing activities of the adult birds during the breeding season. Our results suggested that broadcasting equipment should be capable of producing Sooty Tern colony vocalizations at sound levels at least 85-90 dB, at a distance of about three m from the speakers, in the intended nesting area. Potential human health risks of prolonged exposure to vocalizations within Sooty tern colonies are highlighted.

Protected lands contain a large proportion of existing critical habitat for many wading bird species, but human activities in these areas have the potential to adversely effect these species. The effects of passing vehicles on the foraging behavior of wading birds was studied using observational and experimental methods at the Merritt Island National Wildlife Refuge near Titusville, Florida. Foraging wading birds were more likely to be disturbed when vehicles slowed or stopped adjacent to them, than when vehicles continued driving by. In an area with a high rate of human visitation, some individual wading birds responded more strongly to passing vehicles than did others, suggesting that some were habituated to disturbance. Experimental disturbance by a vehicle caused a significant depression in the foraging rates of the Snowy Egret (Egretta thula) and the Great Egret (Ardea alba) and non-significant reductions in foraging rates in the Tricolored Heron (E. tricolor). Nineteen percent of the birds flushed following disturbance. The proximity of the disturbance vehicle influenced the probability of flushing in a species-specific manner with the Tricolored Heron being the most sensitive, the Great Egret intermediate, and the Snowy Egret the least sensitive. Recommendations to managers include concentrating ecotourism in certain areas and educating ecotourists about the effects of their behavior on wading birds.

We exposed 13 species of waterbirds (Pelecaniformes, Ciconiiformes, Falconiformes) to the direct approach of an airboat to determine their flush distances. Five lakes with different levels of airboat activity were visited in central Florida during April-August 1999 to 2001. We detected considerable variation in flush distances among individuals within the same species and significant differences among species in response to an airboat. Average flush distances among all species ranged from 49 m for the Snail Kite (Rostrhamus sociabilis) to 172 m for the Bald Eagle (Haliaeetus leucocephalus). Average flush distances among herons ranged from 65 m for the Tricolored Heron (Egretta tricolor) to 113 m for the Great Egret (Ardea alba). Larger species generally exhibited greater average flush distances. A comparison of the flush distances elicited by a fast moving outboard-powered boat and an airboat indicated that all nine species exhibited significantly greater flush distances to the approach of an airboat. Recommended buffer zones that would minimize disturbance of waterbirds while foraging and loafing ranged from about 130 m (Snail Kite) to 365 m (Bald Eagle) for raptors and 165 m (Tricolored Heron) to 255 m (Great Egret) for wading birds.

The breeding success of the Cattle Egret (Bubulcus ibis) and Little Egret (Egretta garzetta) was studied in relation to nest site selection. Average nest abundance for the Cattle Egret was 0.045 ± 0.041 (95% CI) nests.m^-3 of canopy volume, and 0.026 ± 0.019 (95% CI) nests^-1 volume³ of canopy volume for the Little Egret. Total estimated population size was 882 nesting pairs (Cattle Egrets = 550; Little Egrets = 332). Cattle Egrets occupied higher trees for nesting than Little Egrets. Both species nested above the middle of the nesting trees. The clutch size of Cattle Egrets averaged 3.03 eggs whereas mean clutch size of Little Egrets was 3.22 eggs. A higher hatching success in the Cattle Egret than in the Little Egret suggested a relationship between nest selection and hatching success.

Mallard (Anas platyrhynchos) may winter in northern areas if they have access to adequate food and open water. We compared individual body size (indexed by first principal component scores from three morphometric measurements) and body condition (body mass adjusted for body size) of male Mallard wintering in North Dakota, USA during 1996-99 with a baseline reference group of Mallard from Ontario, Canada measured during late summer. Size and condition of Mallard wintering in North Dakota was also compared, using a sample from a traditional wintering area in Arkansas, USA. Male Mallard body size and condition in North Dakota relative to weather severity during mid-winter was assessed. Body size of adult males in North Dakota was significantly greater than that of birds from Ontario, but similar to those from Arkansas. Adult males remaining in North Dakota during the coldest winter were not larger than those remaining in North Dakota during milder winters. Immature males in North Dakota were significantly smaller than those from Arkansas, and the former were not larger during the coldest winter. Body condition of adult males in North Dakota was greater than that of those from Ontario and Arkansas and mean body mass of adult males in North Dakota during winter was greater than that of those wintering elsewhere. Further, adult males in North Dakota were in the best condition during the coldest winter. Mean body condition of immature males in North Dakota was similar to that of those from Arkansas. Body mass of immatures in North Dakota was similar to that of immatures wintering elsewhere. These findings indicate that maintenance of high fat reserves, not large body size, is the primary factor allowing adult males to winter in the extremely cold conditions of North Dakota. The small size of immature males in North Dakota, combined with the lack of evidence of their superior condition as compared to those wintering elsewhere, suggests that immatures wintering in North Dakota are mainly late-hatched individuals that may not have been able to store sufficient fat reserves to migrate before freeze-up.

Terns of the genus Chlidonias may be exceptional among the larids in laying the ultimate egg in the clutch-sequence that is not smaller than the earlier eggs. To investigate this, we analyzed data on egg length, breadth, volume and shape in three-egg clutches of the White-winged Tern (Chlidonias leucopterus) breeding in NE Poland. Both length and volume of the c-egg was larger than mean values the a- and b-eggs in the clutch. They also differed in shape. Egg breadth did not differ in such a comparison. Two species of Chlidonias terns do not conform to the typical pattern of larids, in which the last-laid egg is the smallest in the clutch; this may be related to their being insectivorous rather than piscivorous. Chlidonias terns lay eggs of the size expected from the regression of mean egg size on mean female body size in all the Western Palearctic terns.

A census of the Grand Manan Archipelago, New Brunswick, Canada, found nine seabird species nesting at 22 sites. Herring Gull (Larus argentatus) and Common Eider (Somateria mollissima) were the most widely distributed species, with a combined 89% of all breeding seabirds in the region. Although fewer, the Great Black-backed Gull (Larus marinus) and Black Guillemot (Cepphus grylle) were widely distributed. Other seabirds had more limited distributions; one Common Tern (Sterna hirundo) colony, three Double-crested Cormorant (Phalacrocorax auritus) colonies and one mixed colony of Razorbill (Alca torda) and Common Murre (Uria aalge). Leach’s Storm-Petrel (Oceanodroma leucorhoa) numbers were not determined, but were found nesting on three islands and were suspected to be nesting on two others. Comparisons with historical data showed increases in gulls, Razorbill and Common Murre, whereas eiders had remained relatively stable over the past two decades, but had decreased in recent years. Insufficient data are available to assess trends of other seabird species nesting around Grand Manan. Fluctuations in cormorant numbers may be a result of moving breeding sites. The recent decrease in eider numbers may be a consequence of low survival rates of young and increasing numbers of predatory gulls. Considerable discrepancies were observed between recent and historical gull numbers which may have resulted from 1) differences in survey methodology, and 2) survey timing. This study provides estimates of breeding seabirds, which can be used as baseline data for future monitoring in the Grand Manan Archipelago.

The European Shag (Phalacrocorax aristotelis) breeds in a wide range of nest-sites depending on the locality, such as crevices under fallen rocks, open ground caves and open ledges on craggy cliffs. In this paper the habitat selection of shags breeding in cavities on the coastal slopes of Islas Cíes (Galicia, Northwest Iberian Peninsula) are examined. Shags selected sites with more lateral and overhead cover, with better drainage and with average visibility. In addition, sites where breeding was successful differed from unsuccessful sites. Nest-site characteristics especially affected the hatching success. In this colony, shags showed adaptive responses to site-quality variability. Thus, nest-site quality declined with density and with seasonal occupancy. Shag colonies seem to follow an ideal despotic distribution, where some individuals monopolize high quality sites and prevented other individuals from settling in the good sites. Further studies are required to assess the proximal mechanisms used for nest-site selection in this species.

In coastal environs during the non-breeding season, many shorebirds (suborder Charadrii) congregate at roosts, long considered to be traditional sites where flocks of individuals coalesce when high tides inundate feeding areas. Humboldt Bay, California was surveyed (9.5 months at roughly 10-d intervals) to assess temporal variation in incidence (proportion of 28 surveys birds used a roost), proportional abundance, concentrations, and repeatability (of seasonal average proportional abundances) of shorebird use of diurnal, high-tide roosts. Two hundred and forty roosting locations were identified and observations were made of 30 species. Fourteen species accounted for over 99% of observations. Shorebirds occurred at most roosts infrequently (<20% of surveys) and only 4% of roosts had roosting birds present on more than 80% of occasions. Abundant species occurred at more roosts (20-141 roosts per species) compared with less common species. Even at the most-used roosts, abundances at the species level varied greatly. Repeatability of roost use among seasons was high. At Humboldt Bay, roost use formed a continuum from ephemeral locations used by a few birds to sites used consistently by large numbers of individuals.

We identified environmental variables and grassland characteristics that affect the use of natural grasslands by four migratory shorebird species (Patagonian: Rufous-chested Dotterel (Charadrius modestus) and Tawny-throated Dotterel (Oreopholus ruficollis); Nearctic: American Golden Plover (Pluvialis dominica) and Buff-breasted Sandpiper (Tryngites subruficollis)) during the non-breeding season in the flooding pampa region of Argentina. Birds were recorded using fixed-radius point count method, every 15 days between April 1999 and January 2000. A stepwise forward logistic regression was used to examine the relationship between the presence of shorebirds and grassland characteristics and environmental variables. All species correlated positively with the variable “previous use” suggesting strong site fidelity within years to a wintering site. All species correlated negatively with the percentage of high grass cover, and the American Golden Plover and Buff-breasted Sandpiper both correlated negatively with soil water content. Tawny-throated Dotterel correlated positively with the presence of Stipa neesiana. Previous studies have identified the coastal grasslands of Buenos Aires province as important sites for wintering nearctic and Patagonian grassland shorebirds. This study confirms the importance of this area, and highlights the important role that sheep management plays in maintaining suitable habitat conditions (short grass) for grassland shorebirds.