The grey-winged cotinga Tijuca condita was first described in 1980 from an old specimen, misidentified as a congener. Field observations came later, from two remote, high-elevation forests in the mountains of Rio de Janeiro, Brazil. Both involved only a few pairs of birds at best, making this species one of the least known in the world. Accurately defining the locations this species inhabits is an obvious prerequisite for designing conservation strategies to protect it. Using remotely sensed data on elevation and forest cover we mapped this species’ habitat and predicted six more sites where it may occur. Field surveys confirmed two of them, doubling the known range of the species. The two easternmost predicted sites did not contain the species but these areas have less annual rainfall than other sites, which may explain the absences. This research serves as an important guide to conservation actions, for it uncovered biologically important areas for this species that had been previously overlooked. It has also measured the remaining habitat of the species so that any future losses can be detected.

Managers in southern Africa are concerned that continually increasing elephant populations will degrade ecosystems. Culling, translocation and birth control are flawed solutions. An alternative is providing elephants more space but this hinges on identifying landscape preferences. We examined two diverse ecosystems and uncovered similarities in elephant habitat use, expressing these as ‘rules’. We considered arid Etosha National Park, (Namibia) and the tropical woodlands of Tembe Elephant Park (South Africa) and Maputo Elephant Reserve (Mozambique). Landscape data consisted of vegetation types, distances from water and settlements. To surmount issues of scale and availability we incorporated elephant movements as a function that declined as distance from an elephant's location increased. This presumes that elephants optimize trade-offs between benefiting from high-quality resources and costs to find them. Under a likelihood-based approach we determined the important variables and shapes of their relationships to evaluate and compare models separated by gender, season and location. After considering elephants' preferences for areas nearby, habitat use usually increased with proximity to water in all locations. Elephants sought places with high proportions of vegetation, especially when neighbouring areas had low vegetative cover. Lastly, elephants avoided human settlements (when present), and cows more so than bulls. In caricature, elephants preferred to move little, drink easily, eat well, and avoid people. If one makes more areas available, elephants will probably favour areas near water with high vegetative cover (of many different types) and away from people. Managers can oblige elephants’ preferences by supplying them. If so, they should anticipate higher impacts to neighbouring vegetation.

Cercomacra carbonaria and Synallaxis kollari are passerine birds endemic tothe gallery forests of Roraima state in northernmost Brazil and adjacent Guyana.The IUCN Red List of Threatened Species lists both as Vulnerable but they havebeen removed from Brazil's list of threatened species because of datadeficiency. They are poorly known, reflecting both Roraima state'sdistance from Brazil's main population centres and the inaccessibilityof their habitat. In 2004 and 2005, we conducted bird surveys along the majorrivers that provided previous sightings, and expanded records from only ahandful to several dozens. We found C.carbonaria at 29% of the points surveyed, and estimated its localpopulation density at approximately 80 individuals km−2and total population size to exceed 15,000 individuals. The species has 723km2 of available habitat, 8% of which is inside conservationunits. We found S. kollari at 44% of thepoints surveyed, and estimated its local population density as approximately 60individuals km−2, with an estimated total population sizeexceeding 5,000 individuals. It has 206 km2 of available habitat,none of which is inside conservation units. We recommend that C. carbonaria be down-listed on the IUCN Red Listto the Near Threatened category, and that S.kollari be listed as Endangered. Both species live in areasvulnerable to habitat loss. We also recommend that both species re-enter theBrazilian list of threatened species and highlight the importance of indigenousreserves to their conservation.

Resumo

Cercomacra carbonaria e Synallaxis kollari são avespasseriformes das matas de galeria do Estado de Roraima em sua parte mais aonorte do Brasil e da Guiana adjacente. Ambas as espéciessão catalogadas como “Vulneráveis”pela lista vermelha de espécies ameaçadas da IUCN, masforam excluídas da lista de espécies ameaçadasdo Brasil devido è insuficiência de dados. Estasespécies são pouco conhecidas, refletindo tanto adistância do Estado de Roraima dos principais centros urbanos quantoa inacessibilidade do seu hábitat. Em 2004 e 2005, realizamos censosde aves anteriormente avistadas ao longo de rios maiores, aumentando assim osregistros de apenas alguns poucos números para diversas dezenas.Encontramos C. carbonaria em 29% dos pontosamostrados e estimamos sua densidade local em ∼80indivíduos km−2 e o tamanho populacional totalem mais de 15.000 indivíduos. A espécie possui 723km2 de habitat disponível, 8% do qual estáincluído em unidades de conservação.Encontramos S. kollari em 44% dos pontosamostrados e estimamos sua densidade populacional local em ∼60indivíduos km−2, com uma estimativa de tamanhopopulacional total em mais de 5,000 indivíduos. Estaespécie tem 206 km2 de habitat disponível,nenhum dos quais incluído em unidades deconservação. Recomendamos que C.carbonaria seja rebaixada para a categoria ‘QuaseAmeaçada’ e S. kollaricategorizada como ‘Ameaçada’ na lista vermelhada IUCN. Ambas as espécies vivem em áreasvulneráveis em relação è perda deseu hábitat. Recomendamos, também, que ambas asespécies sejam re-incluídas na lista deespécies ameaçadas do Brasil, destacando aimportância das reservas indígenas para a suaconservação.

A companion paper in this issue describes the mapping of Cape Sable seaside sparrow (Ammodramus maritimus mirabilis) habitat using satellite imagery. In general, those maps are correct. However, testing against an independent survey of the sparrow population does identify errors. Those errors fall into two categories, model errors and bird errors. The model errors result from genuine problems with the model. More interesting for conservation are the bird errors, which are more numerous. They are of two types. (1) Commission errors: some suitable habitat does not contain birds. These are areas where prior events have depleted sparrow numbers, but because the sparrows do not disperse long distances, they cannot occupy it quickly. (2) Omission errors: some birds remain in unsuitable habitat that was formerly suitable. This results from the sparrow's very high site fidelity. Often, they will not leave an area even when it is no longer suitable. The consequences of these bird errors are that some habitat and some birds are not contributing to the species' survival. Thus, an estimate of only the amount of habitat or only the sparrow population may present an overly optimistic view of the sparrow's plight.

The Cape Sable seaside sparrow (Ammodramus maritimus mirabilis) is Federally protected under the Endangered Species Act of the United States of America. This legislation prohibits direct or indirect take - the killing or harming - of the protected species. In 1993 and 1995, the opening of floodgates into Everglades National Park during the normal dry season resulted in a direct take of the sparrow. The argument was also made that there was indirect take through destruction of the habitat upon which the sparrow depends. Using a combination of fieldwork and satellite image analysis, we show that the floods did damage to the habitat of the sparrow. Moreover, they did so for a period longer than the actual flooding, further increasing the sparrow's extinction risk. Recovery of the sparrow population to pre-flood levels will require an adequate and stable amount of habitat. We now have a technique for monitoring that habitat and ensuring that poor water management does not threaten it. More broadly, this technique has the potential for monitoring the habitat of many other species and avoiding another situation such as the sparrow faces.

Field ecologists in Everglades National Park know that the dynamics of water flow affect the breeding success of wading birds. A number of recent studies have suggested foraging success as the primary causal link. Data on the number and location of foraging birds are available from the Systematic Reconnaissance Flights, monthly aerial surveys of wading birds and surface water condition. A set of regression models were developed that predict the number of foraging birds observed in the Park at the beginning of May, a crucial period in the breeding season of almost all wading birds in this area. Predictor variables were obtained by converting the observations of surface water condition into three indexes that describe (1) the amount of surface water in the Park in January (near the beginning of the ‘dry’ season), (2) the rate at which it dries over the subsequent months, and (3) the amount of disruption to that drying process. An information-theoretic measure, ICOMP(IFIM), was used to choose on the basis of parsimony between the large set of possible models that incorporate these predictors. Most species were best predicted by the same few models, and the fitted model parameters were also similar, indicating that the same pattern of surface water dynamics was optimal for most species. The optimal pattern was: intermediate water levels at the beginning of the dry season, a rapid rate of drying, and no disruption in the drying process. A number of disruptions in drying since 1985 have been the result of releases of water from the flow-control structures at the northern boundary of Everglades National Park. Reducing or eliminating these unnatural hydrological events should help wading bird populations to increase.

The Cape Sable seaside sparrow is a Federally listed endangered species endemic to south Florida's Everglades. It nests near the ground in seasonally dry prairies. Consequently, the timing and depth of seasonal water flows determine its fate. With water management plans the central focus of Everglades' restoration schemes, the demography of this bird becomes central to hydrologic planning. In order to understand how its demography influences restoration options, we calculated survivorship, fecundity and dispersal within three of the sparrow's six populations. Nearly 40% of adult sparrows die from year to year. Sparrows can produce up to four broods per breeding season, and typically produce two (March to August). Females lay an average of three eggs per nest, two of which usually hatch. The success of these nests varies among populations such that nests in population E are more than four times as likely to fledge young as nests within population A. Nest success within population B is 26% early in the breeding season, but drops to 9% after the onset of summer rains in early June. Nests are built 16 to 21 cm from the soil surface making them vulnerable to water depths that exceed these values. Based on observations of marked individuals, sparrows generally remain within a 1 km area centred on their breeding grounds. We have never observed immigration between populations. A simple demographic model demonstrates that breeding success and duration appear to constrain sparrow population growth more than other demographic parameters. Maintaining suitable breeding conditions restricts water management options to those that will restore hydrological conditions to their original patterns.

We tabulate three measures of rarity: local abundance, breeding range size and elevational extent for the passerine birds of the New World. We determine what fraction of species is threatened with extinction within the combinations of these three measures. Species with smaller ranges, lower abundances and narrower elevational bands suffer higher levels of threat across lowland, montane and island species. For a given range size, lowland species suffer higher levels of threat than island or montane species. (This is counter to the intuition that island species — and those isolated on mountain tops — might be ecologically naïve.) When all three factors are considered together, there is only a slight tendency for lowland species to be disproportionately more threatened. Simply, island and montane species tend to be relatively common within their restricted ranges and their increased abundance reduces their likelihood of being threatened. Elevation is a consistent but relatively unimportant factor in determining threat; abundance and range size are much more important, and have an interactive effect on threatened status. We calculate the number of humans with which each species shares its breeding range, and find that this number does not aid in predicting threat status.

The elephant population in Kruger National Park, Republic of South Africa, is growing rapidly. To prevent damage to the Park's ecosystems, the management has culled about 7% of the population annually. Such culls are very controversial. At first glance, contraceptives seem an attractive alternative means of control. We examine contraception as a management option, review the relevant aspects of elephant reproduction, physiology and demography and conclude that this optimism is probably misplaced. First, contraceptives have a wide range of physiological and behavioural side-effects that may prove to be damaging to the individual female and those around her. Second, the elephants in the Park have near-maximal growth rates with inter-calving intervals of less than four years. To achieve zero population growth, about three-quarters of the adult female elephants would need to be on contraceptives. There are no simple alternatives. The smallest numerical target for controlling population numbers is to kill or sterilize females about to become pregnant for the first time. Such a solution is unlikely to appease those who consider killing elephants to be unethical. It may, however, be the one closest to the natural patterns of elephant mortality.

The Cape Sable seaside-sparrow (Ammodramus maritimus mirabilis) has disappeared from its only known breeding areas episodically since its discovery early this century. Systematic surveys across its range in the southern Everglades find the sparrow's range to be fragmented into six subpopulations. The sparrow population decreased by 58% between 1992 and 1995, with the near extinction of the western half of the population and the temporary local extinction of some eastern populations. Other similar grassland sparrows have populations that vary considerably from year to year. Yet the decline in the western subpopulation and the local extinction of some of the peripheral populations cannot be explained by natural variability alone. Hurricane Andrew passed over several subpopulations prior to the particularly poor year of 1993. However, the geographical and temporal patterns of subpopulation decline are not consistent with what would be expected following a hurricane. Frequent fires prevent successful breeding as does flooding during the breeding season. Better management can prevent frequent fires and episodic flooding. However, the long-term survival of the sparrow depends on managing the unanticipated risks that attend its small, fragmented population.

The legally endangered Cape Sable seaside-sparrow (Ammodramus maritimus mirabilis) is restricted to short-hydroperiod, marl prairies within Florida's Everglades National Park and Big Cypress National Preserve. Marl prairies are typified by dense, mixed stands of graminoid species usually below 1 m in height, naturally inundated by freshwater for 3–7 months annually. Water levels affect the birds directly, by flooding their nests, and indirectly by altering the habitat on which they depend. Managed redistribution of water flows flooded nearly half of the sparrow's geographical range during several consecutive breeding seasons starting in 1993. Furthermore, these high water levels rapidly changed plant communities, so jeopardizing the sparrow's survival by reducing the availability of nesting habitat.