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The Galápagos archipelago is characterized by a high degree of endemism across many taxa, linked to the archipelago's oceanic origin and distance from other colonizing land masses. A population of ~500 American Flamingos (Phoenicopterus ruber) resides in Galápagos, which is thought to share an historical origin with the American Flamingo currently found in the Caribbean region. Genetic and phenotypic parameters in American Flamingos from Galápagos and from the Caribbean were investigated. Microsatellite and mitochondrial DNA markers data showed that the American Flamingo population in Galápagos differs genetically from that in the Caribbean. American Flamingos in Galápagos form a clade that differs by a single common nucleotide substitution from American Flamingos in the Caribbean. The genetic differentiation is also evident from nuclear DNA in that microsatellite data reveal a number of private alleles for the American Flamingo in Galápagos. Analysis of skeletal measurements showed that American Flamingos in Galápagos are smaller than those in the Caribbean primarily due to shorter tarsus length, and exhibit differences in body shape sexual dimorphism. American Flamingo eggs from Galápagos have smaller linear dimensions and volumes than those from the Caribbean. These findings are consistent with reproductive isolation of the American Flamingo population in Galápagos.
Range expansion of native as well as exotic species often causes effects on the original species; however, not all range expansions are negative for breeding colonies consisting of mixed species. The Grey Heron (Ardea cinerea) has increased and expanded its distribution in Japan in the last 20 years. Its solitary and early nesting habits may facilitate establishment and persistence of colonies of mixed heron species. To examine whether the addition of Grey Herons has affected colony persistence and the number of established and abandoned colonies, 16 years of monitoring data from before and after the expansion of Grey Herons around Ibaraki Prefecture in Japan were analyzed. Most newly established colonies were without Grey Herons before their expansion, but more than half of the established colonies contained Grey Herons after the expansion. The number of colony abandonments decreased after the Grey Heron expansion and most of these occurred in colonies that were without Grey Herons both before and after the expansion. Persistence periods were longer in colonies with Grey Herons than in colonies without Grey Herons. The expansion of Grey Herons into mixed heron colonies has promoted the persistence of mixed heron colonies, and local populations of colonial herons seemed to gain the benefit of colony sustainability.
The American Oystercatcher (Haematopus palliatus) is listed as a Species of High Concern in the United States Shorebird Conservation Plan due to a small population size and threats during its annual cycle. Previous studies of the American Oystercatcher have focused on Atlantic Coast populations; however, little is known about the reproductive success of the western Gulf Coast population. The objective of this study was to determine nest and brood survival of American Oystercatchers in Texas. A total of 337 nests and 121 broods were monitored on the Texas Gulf Coast during 2011–2013. The top model for nest survival in Program MARK included a linear decline in survival across the nesting season and as nests aged. Survival also declined as island size and foraging habitat near the nest site increased. The probability of a nest surviving from mean initiation date to hatching was 0.384 (95% CI = 0.317, 0.451). The top model for brood survival included a linear decline in survival across the season and an increase in survival as broods aged. Brood survival also varied among years and coastal region. The probability of a brood surviving from mean hatch date to 35 days after hatch ranged from 0.397 (95% CI = 0.204, 0.578) in 2013 to 0.887 (95% CI = 0.673, 0.964) in 2011 across all regions. Known causes of nest and brood loss included beach overwash, depredation, and starvation. This study provides the first estimates of nest and brood survival of the American Oystercatcher along the western Gulf Coast. The additional insight into patterns of nest and brood survival in this species will be useful for future conservation planning efforts that target breeding American Oystercatchers.
Waterbirds breeding on the Mongolian Plateau in Central Asia must find suitable wetland areas for nesting in a semiarid region characterized by highly variable water conditions. The first systematic nesting study of a waterbird dependent on this region for breeding was conducted on the Bar-headed Goose (Anser indicus). The purpose of this study was to document Bar-headed Goose nesting locations, characterize nests and nesting strategies, and estimate daily nest survival (n = 235 nests) from eight areas of west-central Mongolia across three summers (2009–2011) using a modified Mayfield estimator. Bar-headed Goose daily nest survival ranged from 0.94 to 0.98, with a 3-year average nest success of 42.6% during incubation. Bar-headed Geese were found to primarily nest on isolated pond and lake islands as previously reported, but were also documented regularly, though less frequently, along rocky cliffs in several regions of west-central Mongolia. Daily nest survival was higher for cliff nests than for island nests. Information-theoretic models indicated that nest survival decreased with nest age and varied annually with changing environmental conditions. Results of this study suggest that while Bar-headed Geese primarily rely on nesting island sites these sites may be more susceptible to anthropogenic disturbance and predation events influenced by seasonal variation in environmental conditions, and that higher daily nest survival values documented for the less frequent cliff nest strategy may provide an important alternative strategy during poor island nest success years. Thus, conservation efforts for this and other waterbird species in the semiarid region should be focused on conserving nesting islands and protecting them from disturbance in areas of high livestock densities experiencing a rapidly warming climate.
Accurate estimates of population size and trends are often necessary for wildlife conservation, but imperfect and variable rates of detection can lead to substantially biased counts during surveys. The influence of survey timing relative to timing of breeding on the counts recorded for five shorebird species during transect surveys at East Bay, Nunavut, Canada, from 2000 to 2010 was examined. Transect counts varied widely among species and years, and transect counts were most strongly predicted by the density of nests found during more intensive surveys. However, after accounting for this variation, survey counts were influenced substantially by survey timing. Surveys carried out shortly after the median date of nest initiation (∼2 days after) corresponded most closely to the densities of found nests, and if surveys were not within several days of the median date, the discrepancy between the two estimates was large. Although neither nest densities nor transect surveys are believed to be a perfect indication of local population status, these results suggest that the nearly inevitable variation in survey timing could introduce substantial bias into density estimates.
Wetlands are under enormous pressure due to rapid economic development in China. Waterbirds, which depend on wetlands, are therefore facing a dramatic threat. Surveys were conducted in 19 Provinces in the winters of 2011/2012 and 2012/2013. Sites that support internationally important numbers of waterbirds were selected. Seven sites that support 20,000 or more waterbirds and 48 sites that support more than 1% of the global or flyway population of at least one species were found in our survey. Ten (20.8%) of these sites were protected and 10 (20.8%) had no protection. Eight of the 10 unprotected sites were located along coastlines. Of 16 coastal wetland sites, 43.8% were unprotected. The protection of wintering sites of waterbirds should be made a priority and more wetland sites, especially coastal wetland sites, should be protected. Additionally, an intensive site survey should be conducted to gain comprehensive knowledge of the distribution of wintering waterbirds in China to better protect waterbirds and their habitats.
Gisele Pires de Mendonça Dantas, Larissa Rosa de Oliveira, Anna Carolina Milo Marasco, Jansen de Araujo, Renata Hurtado, Edison Luiz Durigon, Luis Francisco San Fillipo, João Stenghel Morgante
There is growing evidence that during the past 100 years the climate of the Antarctic Peninsula has changed from a relatively cold environment to an increasingly warmer one. The penguins that breed in the region are sensitive to oceanographic environmental and climatic conditions. They are considered the bellwether sentinels of the ocean because of their sensitivity to environmental changes. The present study aimed to determine the evolutionary history of the Gentoo Penguin (Pygoscelis papua) and Adélie Penguin (Pygoscelis adeliae) at Admiralty Bay, King George Island. A population genetics approach was used to examine the genetic variability of the two penguin species, searching to infer their demographics histories. The D-loop region from the mitochondrial DNA was sequenced in Adélie (n = 53) and Gentoo (n = 29) penguins. These species showed high genetic diversity, reflecting a large ancestral population size. The results also revealed that the Gentoo Penguin has had a stable population over the last 500,000 years, whereas Adélie Penguins showed a signal of population expansion estimated to have occurred between 300,000 to 400,000 years ago. Results indicate that penguin species respond differently to climate change and that Adélie Penguins are more sensitive to such changes. High genetic diversity and stability of the populations in recent centuries could be important for predicting the response to future events.
The Scarlet Ibis (Eudocimus ruber) and White Ibis (Eudocimus albus) are often classified as separate species, but differing scientific opinions exist regarding the taxonomic status of these birds, as they exhibit similar behavior and hybridize in nature. The present study provides genetic data to help clarify this taxonomic issue. DNA was extracted from 10 individuals of each taxon from the states of Florida, USA (White Ibis) and Amapá, Brazil (Scarlet Ibis). The sequences of three mitochondrial and four nuclear markers were obtained from all individuals. The Scarlet Ibis and White Ibis did not share any haplotypes in mitochondrial genes nor in one nuclear marker. Species delimitation using Bayesian analysis, the Knowles-Carstens method and the genealogical sorting index demonstrated the Scarlet Ibis and White Ibis to be two different lineages and revealed a strong signal of speciation despite the polyphyly found in three of the four nuclear markers.
Little information exists on nesting by seabirds and coastal waterbirds in Panamá. The present study of the Gulf of Chiriquí complements our previous study of nesting waterbirds of the Gulf of Panamá. In April 2012, about 4,000 nests of seven species of seabirds and other colonial waterbirds were identified during a complete survey by small plane and boat within and adjacent to the Gulf of Chiriquí. Seventeen colony sites were found, 12 of which are reported here for the first time. Nesting species included Brown Booby (Sula leucogaster; the most abundant species with nearly 2,500 nests), Brown Pelican (Pelecanus occidentalis), Magnificent Frigatebird (Fregata magnificens), Bridled Tern (Onychoprion anaethetus; second nesting site for Panamá), Wood Stork (Mycteria americana; third nesting site for Panamá), Great Egret (Ardea alba), and Cattle Egret (Bubulcus ibis). The largest nesting site in the Gulf of Chiriquí was the Islas Ladrones, with 2,200 Brown Booby nests (the largest site for this species in Panamá) and 130 Magnificent Frigatebird nests. Unlike most of the sites found in this study, these islands are not currently officially protected.
This study provides the first detailed information on the migration routes and stopover sites for the endangered Scaly-sided Merganser (Mergus squamatus) breeding in Northeast China. Scaly-sided Mergansers (n = 4) were tagged with Platform Transmitter Terminals at Dailing in the southeastern Lesser Xingan Mountains of China during the late breeding seasons of 2010 and 2011. Two Scaly-sided Mergansers completed their autumn migration across the Yellow Sea, lasting 58 and 26 days, respectively, arriving on their wintering grounds at Yuanjiang River in Hunan Province and Xiushui River in Jiangxi Province of China. Both of the Scaly-sided Mergansers stopped at four sites and travelled 2,600 km from their breeding to wintering grounds. After a stay of 120 days, one of the marked individuals departed its wintering ground and returned to Dailing on 19 April 2012 and used a similar route as that in autumn migration and stopped at two sites. Wetlands at Ryonghung Gang estuary in North Korea, Yunshui River and Chidong Lake in Hubei Province of China, and Songjiang River in Jilin Province of China were used as major stopover sites. The determination of previously unknown wintering grounds and stopover sites in China and North Korea provides opportunity to discover more populations of the Scaly-sided Merganser outside its breeding areas.
During the 2010–2011 and 2011–2012 breeding seasons (November to June), there were 21 colonies of 13 species, with at least 40,000 to 50,000 pairs of seabirds on six islands of Bahía Santa María-La Reforma in Mexico. Bahía Santa María maintains the largest breeding congregation of the west coast of Mexico for Laughing Gull (Leucophaeus atricilla; 22,000 pairs), Royal Tern (Thalasseus maximus; 11,000 pairs) and Black Skimmer (Rynchops niger; 1,500 pairs). In the past decade, most of the species that breed on El Rancho Island (coastal dune habitat) have increased their population size, apparently related to a combination of factors such as colonies recently established (and hence still expanding) and increased habitat availability. On the other hand, species breeding on islands with mangroves seem to be decreasing (in particular the Brown Pelican (Pelecanus occidentalis) population), but with no obvious reason to explain these low numbers of some species. Despite the small size of the islands used by breeding seabirds, this coastal system supports important seabird populations and its conservation should be a priority.
Mass strandings of seabirds occur frequently on many beaches worldwide and commonly involve penguins, petrels, shearwaters, and prions, among others. Large numbers of stranded albatrosses are rarely reported. In this paper, an unusual stranding event that involved five species of Procellariiformes, predominantly the Atlantic Yellow-nosed Albatross (Thalassarche chlororhynchos), is described in southern Brazil. Carcasses and debilitated specimens of Atlantic Yellow-nosed Albatrosses (n = 125), unidentified petrels/shearwaters (Procellariidae; n = 63), White-chinned Petrels (Procellaria aequinoctialis; n = 52), Great Shearwaters (Puffinus gravis; n = 11), Manx Shearwaters (Puffinus puffinus; n = 4) and Cory's Shearwater (Calonectris borealis; n = 1) were found stranded between 15 and 22 March 2013. Atlantic Yellow-nosed Albatrosses (n = 20) and White-chinned Petrel (n = 1) were found alive and remained in the rehabilitation center for a few days before being released. A total of at least 256 birds were affected during the 8 days of the event, but a larger number likely remained undetected. Rescued Atlantic Yellow-nosed Albatrosses were not emaciated, and the causes of their stranding remain unknown. Equal or greater numbers of stranded petrels had been recorded previously in the area, but strandings of a large number of albatrosses are unusual in southern Brazil and elsewhere.
Diving abilities of fledging Brown Boobies (Sula leucogaster) were characterized during the transition to independence period, and potential inter-sex differences (females are larger than males) were evaluated. Mean and maximum diving depths and mean dive duration increased gradually following the fledglings' first flights. The diving rate and the proportion of active dives (U type) increased notably between days 21 and 25 after first flight. However, maximum dive duration was not influenced by time since first flight, and none of the dive variables evaluated was influenced by sex. In Brown Boobies, acquisition of diving abilities by juveniles is a gradual process, and this can be an important driver of their extended post-fledging parental care.
Many techniques to evaluate survival and movement of wildlife rely on the capture and instrumentation of individuals. However, effective capture techniques for Great Egrets (Ardea alba) outside the breeding season remain elusive, particularly a method to attain robust sample sizes to investigate several aspects of biology. A handheld pneumatic net gun method was developed and successfully captured 97 Great Egrets in 121 trap days. No direct mortalities or substantial injuries occurred. The handheld pneumatic net gun was more cost-effective than commercially available or similar devices, and could prove useful for sensitive species where injury or mortality must be minimized or where the use of explosive devices is restricted.
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