In Northwestern Mexico, approximately 40 breeding species of seabirds have been reported, with several threats (e.g., invasive species introduction and habitat loss) affecting the viability of their populations. As such, it is necessary to take action for their protection. To prioritize conservation activities, 119 reports (governamental agency monitoring programs, grey literature, and scientific literature) were analyzed for research and monitoring results from 1922-2018 (93 of 119 published after 1990) and ranked the different islands (91 sites, including archipelagos with multiple islands) based on their breeding seabird communities (35 species in 11 seabird families, including 7 endemic breeders). For the ranking exercise, three criteria were considered: conservation category, preferred habitat, and foraging guild for each species. Taking into consideration the breeding species on each island, an index to rank the islands was created. Ten islands or archipelagos have high conservation priority (index score > 10 = high priority; mean index = 4.7, median = 5.0, max = 17.9, n = 91), and the most important are: Revillagigedo and San Benito archipelagos, Coronado, San Lorenzo, and Natividad Islands. It is necessary to use new tools and techniques to determine populations' sizes and trends and to create a baseline to compare with future studies. Furthermore, many of the species breeding or feeding in the Mexican Economic Exclusive Zone migrate to other latitudes, elevating the conservation problem to an international scale.

Population genetic structure can aide in developing conservation and management strategies by characterizing populations on local and regional scales. The Elegant Tern (Thalasseus elegans) has a restricted breeding range, with a majority of its nesting population historically found on Isla Rasa, Gulf of California, Mexico. Since the late 1950s, increased frequency of low marine productivity due to warm oceanographic anomalies, such as El Niño events, have caused northward expansion of Elegant Tern breeding colonies into southern California, USA. To test the hypothesis that high gene flow occurs between Gulf of California and southern California Elegant Tern breeding colonies, restriction-site associated DNA sequencing was used to analyze 5,510 single nucleotide polymorphisms from 69 Elegant Terns sampled across four known breeding sites: Isla Rasa, Mexico (n = 30), San Diego National Wildlife Refuge, USA (n = 17), Bolsa Chica Ecological Reserve, USA (n = 11), and Port of Los Angeles, USA (n = 11). Analyses revealed little population subdivision, with non-significant genetic differentiation (F_ST) among sites and no geographic association of individuals, but there was subtle clustering of individuals by breeding site. These results suggest a strong degree of gene flow among the Gulf of California and southern California nesting colonies and indicate that Elegant Terns have a fluid breeding distribution and move readily among nesting sites.

Although sleep is necessary for maintaining physiological and cognitive function in birds, nocturnal sleep behavior has yet to be documented for terns. Nocturnal sleep behavior and vigilance of incubating Common Terns (Sterna hirundo) were explored at two colonies, Gull Island (Ontario, Canada) for six years, and Little Island (New York, USA) throughout one breeding season, using ∼1-min interval, time-lapse images from infrared trail cameras. Behavioral posture and vigilance (eye[s] open) of visible study birds were recorded from the images to determine if these differed between the two colonies. Terns utilized two sleeping postures, Back Sleep and Front Sleep, nearly identical to those used by gulls. Differences in the proportion of time spent sleeping between the two colonies were surprisingly large. Terns at Gull Island spent 75% less time in Back Sleep (deep-sleep posture, 7% of the night) than those at Little Island, and 64% of night with their eyes open (vs. <20% at Little Island). Differences between the study sites that may have caused this disparity include predation risk, colony size, vegetation cover and the presence of other nesting waterbirds. Apparent, long-term sleep deprivation at Gull Island may have physiological impacts. Further research is needed to establish causes and effects of differences in nocturnal sleep behavior in Common Terns.

The Spot-flanked Gallinule (Porphyriops melanops) is an endangered wetland-dwelling bird in Colombia. A field experiment was conducted to experimentally quantify the gallinule's food consumption and the nutritional relationships among the food resources it consumes, i.e., whether the abundance of one resource changed the consumption of another. Three wetland plant species were used for the experiments (Limnobium laevigatum, Hydrocotile ranunculoides, Azolla filiculoides), along with sesame seeds (Sesamum indicum) as a surrogate for a seed food source. Pairwise comparisons were made to determine food consumption when resources were equally available (first experiment), and after augmenting the most consumed resource in the previous experiment (second experiment). The gallinules behaved selectively during both experiments, and the value of the foods based on consumption was: L. laevigatum > S. indicum > H. ranunculoides > A. filiculoides. However, in the second experiment, L. laevigatum and S. indicum were equally consumed. Food preferences of the least consumed food in the first experiment indicated that in two pairwise comparisons the resources were perfect substitutes. In three pairwise comparisons the resources were treated as complementary, whereas two resources had an antagonistic relation. In conclusion, the gallinules' preferences depended on the context, and keeping mixtures of the preferred and complementary food resources available for the gallinules may improve the quality of wetlands.

The Madagascar Pond-heron (Ardeola idae) is a migratory species that breeds exclusively in Madagascar and nearby islands (Europa, Aldabra and Mayotte). Changes in the population of this species were investigated over the last 23 years through literature reviews, field monitoring, and surveys undertaken from 1993 to 2016. Data from 111 sites were collected and analyzed for population assessment, including 11 known breeding sites in Madagascar (n = 6), Mayotte (n = 4), and Europa (n = 1). Trend analyses were done with surveys from 1993-2016 (omitting 1996) and population estimates from the last 5 years of surveys, 2012-2016. The species occurred in all types of wetlands including lakes, ponds, marshes, rivers, mangroves, pasture wet meadow, and rice fields. During the non-breeding season (May-September), many pond-herons migrate to eastern and central Africa; however, some birds (911 records) remained in Madagascar and Mayotte during austral winter. Data show the current population estimated at ∼1100 breeding birds in the total breeding area. The population has declined significantly, with 41.6% and 52.9% declines, respectively, at the two colony sites in Tsimbazaza and Tsarasaotra parks with the longest history of breeding. Main threats to the species are habitat destruction, collection of eggs and fledglings, predation, and human disturbance at all breeding sites.

Few studies on pelecaniform breeding have been conducted in tropical regions. Most species in the Order Pelecaniformes (Family Ardeidae and Threskiornithidae) are facultative brood reduction strategists, laying extra-eggs that might not fledge. In obligate brood reduction in birds, extra-eggs are insurance-eggs, but in facultative brood reduction birds, extra-eggs have historically been interpreted as additional offspring in unpredictable environments. However, this study on six species in Brazil suggests that the insurance-value might be a major factor selecting for extra-egg laying, even in facultative strategists. While Egretta thula, E. caerulea, E. tricolor, Nycticorax nycticorax, and Nyctanassa violacea showed facultative brood reduction strategies, Eudocimus ruber showed a brood survival strategy and was used to compare brood reduction parameters between strategies. Mean brood size in different species ranged from 1.94-2.52 eggs, 1.88-2.25 hatchlings, and 1.65-2.05 fledglings. Clutch sizes were between two and three in brood reduction species, and almost always two in E. ruber, which either raised the entire brood or totally failed. Individual mortality events in non-failed nests were lower in E. ruber. This difference occurred only during the egg stage, when starvation does not occur, so differences between strategies resulted from an insurance-value of extra-eggs. Nest failures were higher in E. ruber. Insurance could be the main force driving evolution of extra-egg laying in facultative species, with survival of additional offspring a collateral benefit.

Temporal variation in the diet of the Kelp Gull in relation to feeding on refuse was studied at a reproductive colony on Isla de las Gaviotas, Uruguay. Diet was assessed temporally within the reproductive season, and inter-annually for 2011 and 2012 reproductive seasons, and the 2013 non-reproductive season. Data analysis was focused on the proportion of the most important diet items recorded in regurgitated pellets: fish and organic refuse. Fish and organic refuse correlated negatively at an intra-monthly scale. Additionally, fish was more frequently recorded during the incubation period (68% of pellets) than during the chick-rearing period (42% of pellets). Conversely, proportion of organic refuse was larger during the chick-rearing period (18% of pellets) than during the incubation period (8% of pellets). During reproduction, fish proportion in diet was larger (2011 = 41% of pellets, 2012 = 32% of pellets) than refuse (2011 = 16% of pellets, 2012 = 15%) and the opposite situation occurred during the non-reproductive season (fish 2013 = 14% of pellets, refuse 2013 = 41% of pellets).

A great variety of waterbirds migrate across western Nevada, where places to rest or refuel are nearly non-existent. One exception is a little-known industrial pond complex at the Albemarle U.S., Inc. facility in Silver Peak. In this paper we analyzed 3 years (2014-2016) of near-daily counts to document the timing, abundance, and stopover biology of 73 species traversing one of the driest regions in North America. Average annual bird-use-days exceeded 350,000, of which 93% were contributed by species with affinities to highly saline habitats. Individuals of most species (total estimated 110,000-183,000) passed through within a day or so, although some Ruddy Ducks (Oxyura jamaicensis), Eared Grebes (Podiceps nigricollis) and American Avocets (Recurvirostra americana) made prolonged stays. We treat the most abundant species in detail and show that data from sites that can be monitored daily can complement studies from sites where daily censuses are not feasible. The Silver Peak ponds attract sufficient shorebirds to warrant consideration as a Site of Regional Importance in the Western Hemisphere Shorebird Reserve Network.

Mediterranean European rice fields provide important habitats for migrating waterbirds. In winter, one waterbird species that particularly benefits from rice fields is the Northern Lapwing (Vanellus vanellus), a species threatened in Europe. To assess the effect of agri-environmental measures on rice field selection and use by wintering lapwings, bird counts were conducted in northeastern Spain during two consecutive winters (2005-2006 and 2006-2007). Information on two mandatory post-harvest management prescriptions of the agri-environment schemes was collected, namely winter flooding (percent ground surface covered by water) and whether fields were rolled or not. The number of lapwings in rolled fields was significantly higher compared to non-rolled fields. For instance, an average rolled field with 50% water cover (percentage at which lapwing abundance more or less peaked) would host an estimated 12.03 ± 0.52 SE lapwings versus 0.18 ± 0.58 in a non-rolled field. While the maximum abundance of lapwings in rolled fields was found at an intermediate percentage of water cover (about 25 to 75%), the number of lapwings increased steadily with water cover in non-rolled fields. Rice post-harvest practices derived from the agri-environment schemes are beneficial for biodiversity, promoting the conservation of suitable habitats for waterbirds.

From July to November 2018, 10 Black-necked Crane (Grus nigricollis) juveniles were tracked using GPS-GSM satellite transmitters to study their migration routes and stopover sites in Yanchiwan Nature Reserve, Gansu Province, China. By the end of the autumn migration in November 2018, more than 25,000 GPS locations had been obtained during tracking. Migration routes, migration distances and stopover sites were determined, and the stopover home range was estimated for each individual. Individuals moved away from Yanchiwan during 2-25 October 2018 and migrated through Da Qaidam, Golmud City, Qumarleb County, Zadoi County, Zhidoi County, and Nagqu City. In mid-November 2018, the birds arrived in Linzhou County, Tibet, China to winter. The migration routes of all individuals were the same, and the average migration distance was 1,500 ± 120 km. Da Qaidam Salt Lake was an important stopover site, with an average stopover duration of 27.11 ± 8.43 d, and the average stopover range of the Black-necked Cranes at Da Qaidam was 27.4 ± 6.92 km². Through field monitoring and satellite maps, the main habitats were determined to be grasslands and wetlands.

In Bermuda, only three species of breeding seabirds survived four centuries of human activity, dating back to the settlement of the archipelago in 1609. This paper reports two consecutive years of nesting data on the Roseate Tern (Sterna dougallii), a historic breeder in Bermuda last recorded breeding in 1849. A pair was discovered incubating an egg on 7 July 2018 on Pearl Island, and a pair, plus one additional adult, returned to this islet to breed in 2019. Roseate Terns and nests were intensively monitored using offshore observations and video recordings. In 2018, the single egg hatched on 24 July and the chick fledged on 18 August (fledging period = 25 d). In 2019, we found a two-egg clutch on 4 June, which hatched on 15 and 17 June. The two chicks were flying by 13 July (fledging periods = 26-28 d). The breeding Roseate Terns in Bermuda are probably derived from the Caribbean/Bahamas population. The two-year nest-site fidelity of Roseate Terns, following absence for at least 140 years, suggests that this species is potentially reestablishing itself as a breeder in Bermuda. Future studies should determine the genetic origin of the birds, determine if the observed pairs are the same individuals using leg bands, record population growth, and compare the nesting biology of Bermudian Roseate Terns to that of the Bermudian Common Terns (Sterna hirundo).

In North America, the Greylag Goose (Anser anser) has been added to the list of vagrant North American waterfowl based on a bird observed in 2005 on a stationary oil ship in the Atlantic Ocean 167 km southeast of the island of Newfoundland, and on single birds observed in Connecticut and Nova Scotia in 2009 and 2010, respectively. Here, feather and toe-claw hydrogen isotope values (δ²H) linked to spatial hydrological hydrogen isotope patterns are used to demonstrate the origin of the first probable wild-origin Greylag Goose known to make landfall in North America. The bird in question, shot by hunters on Grand Manan Island, New Brunswick, in December 2007 and subsequently deposited at the New Brunswick Museum (specimen NBM 11143), was identified as Anser anser and potentially a wild-origin bird. Isotope data indicates the bird is of probable Greenlandic origin. This supports and pre-dates recent (2014) reports of the Greenlandic molting of Icelandic Greylag Geese, until recently believed to molt exclusively on Iceland. Greylag Geese recorded in North America appear to be part of a pattern of increasing numbers and diversity of geese of northeastern Atlantic origin detected in eastern North America in recent decades.