Wetland and Waterfowl research

A B S T R A C T Mediterranean shallow lakes support high biodiversity but suffer many anthropogenic threats, including introductions of alien fish. We studied the impact of introduction of common carp (Cyprinus carpio) to Medina and Zoñar lakes in SW Spain. Both lakes were protected as Ramsar sites because of their importance for waterbirds, particularly the globally threatened white-headed duck (Oxyura leucocephala IUCN Endangered) and common pochard (Aythya ferina IUCN Vulnerable). Two carp introduction events in Medina lake, with total eradication of carp in between, provided a unique opportunity to study the impacts of carp on the waterbird community (counted monthly from 2001 to 2013, with up to 69 species) and submerged macrophyte cover (quantified with satellite images). A comparison of waterbird abundance before and after carp eradication in the smaller Zoñar lake supported the results from Medina lake. Carp consistently led to the destruction of macrophyte beds and a radical change in the waterbird community. After controlling for the influence of depth fluctuations, the numbers and species richness of diving ducks were significantly reduced by carp, whilst the opposite effect was observed for piscivores such as herons. Negative impacts on O. leucocephala, A. ferina, red-crested pochard (Netta rufina) and herbivorous coots (Fulica spp.) were particularly pronounced. A significant negative impact of carp was also recorded on greater flamingos (Phoenicopterus ruber), black-necked grebes (Podiceps nigricollis), little grebes (Tachybaptus ruficollis) and gadwall (Anas strepera). In contrast, carp presence had a positive impact on grey herons (Ardea cinerea). The ongoing expansion of alien cyprinids in the Mediterranean region constitutes a major threat for waterbirds and particularly for sedentary, threatened taxa such as the white-headed duck and red-knobbed coot (F. cristata). Of 22 key sites for the isolated Iberian population of white-headed duck identified in a European action plan in 1996, at least 14 have since suffered carp invasions. Further development of successful control methods for carp populations is urgently required to support the conservation of waterbirds in the Mediterranean region.

Total of 135 waterbird species are recorded in El Salvador. Ten sites are known to contain large concentrations of 10,000 to 140,000 individuals, among which the Cerrón Grande Reservoir (freshwater) and Jiquilisco Bay (coastal, estuarine) stand out. Twelve breeding colonies, with 18 especies, have been documented, but only five of the colonies have protection and are established within protected areas. Just one species is threatened with extinction at the global level (Pink-footed Shearwater, Puffinus creatopus), while at the national level, 32 species are considered threatened or endangered. Only 35 waterbird species breed in El Salvador. Ducks (Anatidae) populations have been monitored during the last five years and recently several breeding colonies have also been monitored. Marine species seem to have the lowest populations (or at least the fewest reports), while Blue-winged Teal (Anas discors), Fulvous Whistling-Duck (Dendrocygna bicolor), Black-bellied Whistling-Duck (D. autumnalis), Neotropic Cormorant (Phalacrocorax brasilianus), Royal Tern (Thalasseus maximus), Brown Pelican (Pelecanus occidentalis), and American Coot (Fulica americana) figure among the most abundant and widely distributed species. A total of 24 species show population increases, including American White Pelican (Pelecanus erythrorhynchos), Boat-billed Heron (Cochlearius cochlearius), White Ibis (Eudocimus albus), Roseate Spoonbill (Platalea ajaja), Limpkin (Aramus guarauna), Black-necked Stilt (Himantopus mexicanus), and Black Skimmer (Rynchops niger). Two species are considered to be in decline: Snowy Plover (Charadrius alexandrinus) and American Oystercatcher (Haematopus palliatus). In all, we estimate the resident waterbird population in El Salvador to range between 259,000 – 397,000 birds, including 95,000 – 197,000 non-breeding visitors (transients or passage migrants not included) and 164,000 – 200,000 individuals of breeding species. On the topic of regulations, El Salvador has adhered to the Convention on Biological Diversity and the Ramsar Convention (three sites are declared Ramsar sites, three other sites are proposed). National laws for wildlife conservation and protected areas exist, but are poorly enforced

The institution of the waterfowl hunting club is uniquely American.  These clubs have played an important part in the conservation of American waterfowl.  They were the first to impose bag limits, bar automatic guns, limit shooting seasons and shooting hours, and the first to create waterfowl rest areas and waterfowl rest days.

Waterfowl hunting was and still is a major form of recreation along the Mid-Atlantic seaboard from the Canadian Maritime Provinces to the Everglades of Florida.  Starting as subsistence hunting and commercial or “market gunning,” it reached its peak as a recreational sport in 1939 with over 44,000 waterfowl sportsmen and nearly 3,000 waterfowl hunting clubs and privately owned hunting marshes.

Waterfowling evolved from subsistence to sport after the Civil War brought prosperity and affluence to broad segments of the Northern population.  The cities of Boston, New York, and Philadelphia became centers of commerce and finance.  Wild waterfowl, considered a delicacy by many, was in great demand in the finer restaurants.  With the rapid expansion of the industrial North, increasing numbers of people found themselves with the means and leisure to engage in waterfowling as recreation.  The construction of the railroads made the transportation of waterfowl to northern markets faster; while at the same time made travel for sport hunters easier.  Market gunners and guides welcomed and needed the additional income provided by the arrival of the northern sportsmen.

Many local families of limited means depended upon work related to sport hunting for seasonal employment.  Entire families were often employed; sometimes over several generations.  Individuals were needed to guide, carve decoys, pick feathers, cook, clean and do laundry, build boats, provide transportation to and from blinds, and maintain and manage the lodges and clubs.

Sadly, waterfowl populations were decimated by market gunners and sportsmen using live decoys, bait, battery guns, spotlights, sink boxes and sneak boxes.  The Federal Migratory Bird Act of 1918 outlawed market hunting and helped to regulate the sport hunter as well.  Federal Regulations in 1937 prohibited sink boxes, bait, live decoys, and limited repeating guns to 3 shells.  The loss of eelgrass due to blight in the 1920s, the Great Depression, and severe storms along the Mid-Atlantic in the 1930s also contributed to the decline of traditional waterfowl hunting and their associated clubs and lodges.

Most sport hunting clubs were private membership entities owned by the wealthy.  Other establishments were commercial lodges available to the more modest hunter.  The eleven Assateague Island “hunting lodges” identified in this historic context study can be separated into three distinct groups: 1) private hunting membership clubs and commercial lodges 2) private non-membership residences where hunting was practiced and 3) private beach houses where hunting was rarely if ever conducted.  The George Gibb’s “hunting shack,” not identified for this study should be included in this inventory as it was used for waterfowl hunting purposes.  These resources are so grouped below:

Private Hunting Membership Clubs and Commercial Lodges

Bob-O-Del Gun Club (corporate)
Bunting’s Gunning Lodge
Green Run Lodge (Jackson Brothers)
High Winds Gun Club (partnership)
Pope’s Island Gun Club (Black Duck)

Private Non-membership Residences Where Hunting Was Practiced

Gibb’s Shack (now naturalist’s shack)
Hungerford’s
People & Lynch
Valentine’s

Private Beach Houses Where Hunting Was Rarely If Ever Conducted.

Clements’ Beach House
Clements’ Boat House
Musser’s

The significance of shantyboats to waterfowl hunting has been largely overlooked.  All five gunning lodges on Assateague Island that are a part of this study either began as and/or incorporated shantyboats into their construction.  At Bob-O-Del Gun Club and High Winds Gun Club two shantyboats were brought up on dry land, expanded, and used as lodging for waterfowl gunning parties.  Bunting’s Gunning Lodge, Green Run Lodge, Pope’s Island Gun Club, and Egging Beach Gunning Club started by using floating shantyboats before land based clubhouses were built.  A shantyboat was also incorporated into the first land-based lodge built at Green Run Lodge.

The Neotropical Cormorant (Phalacrocorax brasilianus) is a common bird in continental wetlands and coastalmarine ecosystems. Nevertheless, there is a lack of information about reproductive colonies, distribution and abundance in El Salvador. We studied the distribution of this species from April to June 2004 in 58 wetlands. In order to consider the abundance by wetland, we carried out counts on the shores of four of them (Güija Lake, Cerrón Grande Reservoir, El Jocotal and Olomega lagoons). Counts were carried out from October to May of 2001-2005. Three colonies (Cerrón Grande reservoir, Bay of Jiquilisco and Güija Lake) were located where we registered nesting events. The species was present in 16 of 58 visited wetlands (27%). The highest number of populations (n = 8) but lowest densities of individuals (100-500 individuals by wetland) were recorded in coastal wetlands. These low numbers, compared with those found in hydroelectric reservoirs (up to 10,000 by wetland) could be due to the residual effect of the use of pesticides in the coastal plain from 1960 to 1982 during the boon of cotton agriculture. In the colonies that we visited, up to 1,359 nests were located. In all the cases P. brasilianus nested in association with others species of the Ardeidae family

This paper summarises discussions by invited speakers during a special session at the 6th North American Duck Symposium on wetland issues that affect waterfowl, highlighting current ecosystem challenges and opportunities for the conservation of waterfowl in North America. Climate change, invasive species, U.S. agricultural policy (which can encourage wetland drainage and the expansion of row-crop agriculture into grasslands), cost and competition for water rights, and wetland management for non-waterfowl species were all considered to pose significant threats to waterfowl populations in the near future. Waterfowl populations were found to be faced with significant threats in several regions, including: the Central Valley of California, the 344 Wetland issues affecting waterfowl © Wildfowl & Wetlands Trust Wildfowl (2014) Special Issue 4: 343-367

Boughaba. No such survey has ever been conducted
before in Morocco to study the change in number of breeding duck species in the country. Overall results
have shown the appearance of new breeding species in the site : Red-crested Pochard (Netta rufina), Common
Pochard (Aythya ferina) and White-Headed Duck (Oxyura leucocephala). Other species have become more
regular like Gadwall (Anas strepera) and Ferruginous Duck (Aythya nyroca) while the vulnerable Marbled
Teal (Marmaronetta angustirostris) and the Mallard (Anas platyrhynchos) continue to breed in this wetland
with numbers that remain stable though the numbers of females with ducklings are decreasing in these two
species. The number of breeding ducks species in this wetland is the highest in Morocco and in the Maghreb.
The overall results showed that the numbers of Gadwall, Red-crested Pochard, Common Pochard and Ferruginous
Duck are markedly increasing following the same expansion patterns at both regional and Mediterranean
levels. The initiation of similar researches on other wetlands is essential to assess the abundance of duck populations
and indicate trends of this breeding waterfowl group at larger scales.

Two tropical species of waterfowl, the Lesser Whistling-duck (LWD) Dendrocygna javanica and Cotton Pygmy-goose (CPG) Nettapus coromandelianus, are patchily distributed across Malaysia and little is known about their habitat requirements. We studied patterns of habitat use for LWD and CPG at the Paya Indah Wetlands Reserve, Malaysia (c. 3,050 ha), by counting the birds from observation points and using a zero-altered negative binomial model to describe their abundance and distribution at the site. Habitat use by LWD and CPG was highly correlated; for instance both species frequented shallow, nutrient-rich lakes in the study area. Fine-scale measures of vegetation characteristics influenced local distribution, whereas a combination of anthropogenic activities and other habitat features best predicted abundance. Overall, LWD selected the more stable but densely-vegetated marshy shoreline while CPG used vegetated areas near the central deeper portions of the lake. Our habitat-selection models give insight into the ecology of LWD and CPG in Malaysia and can provide a tool for identifying areas for possible habitat restoration and conservation in the region.

La temporada de conteos de anátidos se inició en el mes de octubre de 2003 y finalizó en mayo de 2004. Esta se llevó a cabo en cuatro humedales de El Salvador, Lago de Güija, Embalse Cerrón Grande, Laguna de El Jocotal y Laguna de Olomega. Además de los conteos, se realizaron viajes de exploración a dos lagos de origen volcánico: Lago de Ilopango, en la zona central del país y el Lago de Coatepeque en el occidente. El humedal que presentó la mayor abundancia de anátidos es el Embalse del Cerrón Grande con un total de 262,741 individuos, siendo esto el 81% del total de anátidos observados durante toda la temporada. Los conteos mostraron que los meses con mayor abundancia son enero, febrero y marzo, con algunas variantes en cada humedal. Pero la tendencia la marca El Cerrón Grande. En Olomega la mayor abundancia fue en marzo, mientras que en la Laguna El Jocotal fue en diciembre, pero con números considerables hasta marzo. La especie que más abundó durante la temporada es Dendrocygna bicolor, seguido de Anas discors y Anas clypeata. La primera residente y las últimas dos migratoria. Estas tres especies hacen 84% del total de anátidos observados durante la temporada

Redheads, Aythya americana, concentrate in large numbers annually in traditional wintering areas along the western and northern rim of the Gulf of Mexico. Two of these areas are the Laguna Madre of Texas and Chandeleur Sound of Louisiana. We collected data on 54,340 activities from 103 redhead flocks in Texas and 51,650 activities from 57 redhead flocks in Louisiana. Males and females fed similarly, differing neither in levels of feeding (percent of all birds in flock that were feeding) (p>0.90) nor in percentages of birds feeding by diving, tipping, dipping, or gleaning from the surface (p>0.10). The foraging level of redheads in the upper Laguna Madre region was relatively constant throughout two winters. Foraging of redheads in early winter in Louisiana was significantly greater than redhead foraging in the upper Laguna Madre, but by late winter, foraging by redheads in Louisiana had declined to the same level as that shown by redheads foraging in the upper Laguna Madre. The overall foraging level of redheads from Chandeleur Sound was greater (41%) than that of redheads in the upper Laguna Madre (26%), yet it was quite similar to the 46% foraging level reported for redheads from the lower Laguna Madre. Redheads in the upper Laguna Madre region of Texas fed more by diving than did those in the Chandeleur Sound and the lower Laguna Madre. Diving increased in frequency in late winter. Greater reliance by redheads on diving in January and February indicates that the birds altered their foraging to feed in deeper water, suggesting that the large concentrations of redheads staging at this time for spring migration may have displaced some birds to alternative foraging sites. Our results imply that the most likely period for food resources to become limiting for wintering redheads is when they are staging in late winter.

Se presenta una sistematización de actividades de manejo y conservación de recursos naturales, con un enfoque social hacia la comunidad de pescadores de la Laguna El Jocotal y de manejo de vida silvestre, en donde el Pishishe o Pijije de ala blanca (Dendrocygna autumnalis) es el centro del estudio

Regional and intraseasonal patterns of food use influence populations through impacts on breeding success, survival, and distribution of individuals. We used both traditional foregut content analysis and stable carbon and nitrogen isotopes in liver and leg muscle to determine intraseasonal patterns in the diet of Atlantic brant geese (Branta bernicla hrota) from early winter through spring staging (1 Dec-31 May 2007-2008) along the mid-Atlantic coast of the United States. Overall, brant diet consisted of macroalgae (52%), salt marsh cordgrass (22%), eelgrass (18%), and terrestrial grass and clover (8%). Mean d 13 C and d 15 N values differed among these 4 food sources. Therefore, we used an isotope mixing-model (SIAR) to estimate the relative contributions of each source to brant diet among regions and months. Wintering brant in northern and southern regions ate mostly macroalgae throughout the wintering period and ate more salt marsh and terrestrial grasses in spring. Brant in central regions had a more stable diet from December to May. Regional and intraseasonal patterns in brant diet are likely affected by several factors including variation in food source availability and quality due to synergistic effects of long-term annual and intraseasonal changes in abundance of submerged aquatic vegetation. Our estimates of diet combined with information on brant daily energy requirements and forage quality can be used to more accurately determine carrying capacity of wintering brant geese given established population objectives. Ó 2014 The Wildlife Society.